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Noahsnana
02-04-2006, 11:32 AM
Do you always have to use something to stop action?

How many hours does a dose work?

Colors= what level of action?
like...
Purple what is it doing
Brown what is it doing?

sweetpea
02-04-2006, 11:37 AM
NN, I never stop the PP. It
only needs to be stopped if
there's an emergency.
As far as time, that different with
each pond. Can be from 10 minutes
up to a couple of hours. No set time.

Hanover Koi Farms
02-04-2006, 11:45 AM
When it is purple or pink it is doing something, with purple being stonger. When it is brown, yellow, or tea colored it is spent. I usually will deactivate it if the fish have been in pink or purple for 10 hours. I don't like to go past tens hours in those colors. My personal goal is between 6 and ten hours of keeping it purple or pink, and depending on what I am trying to fight or do with it. I will redose it at lower levels if required in the same day, to keep it pink or purple for the desired times. How long it stays pink or purple depends on factors such as organics and or ammonia binders/dechlorinators in the system as well. The hardness will also affect this time.

Go to Roarks site; www.click2roark.com he has a good write up on it there.

schildkoi
02-04-2006, 01:58 PM
PP is "reactive" (to one extent or another) until spent. Its not spent until there is no color of any kind...brown, Tea or otherwise! Let the reaction finish, totally and as stated above, do not reverse unless there is an emergency. By redosing to achieve the desired "reaction time", you are actually increasing the dosage.

I would challenge anyone to tell me at what point there is absolutely no hint of purple in brown water during a PP treatment. Using a simple Orp meter you can see that the ORP will increase beyond that of its initial reading for the initial dosing when redosed at the same measurement.

Steve

Roddy Conrad
02-04-2006, 02:11 PM
Like others say, if there is pink or purple color, the PP is still active, and if there is no trace of pink of a sample taken in a white 5 gallon bucket, you know it is gone.

Also, in general, an ORP reading above 400 indicates residual active PP.

As a sideline to this discussion, a test for chlorine after a PP dose shows active chlorine when there is none, since the chlorine test simply indicates whether an active oxidizer is present or not. Also, for about 12 hours after the PP is spent or reversed, the chlorine test will give a positive reading even though the PP is completely spent or reversed. The point is a chlorine test is meaningless for at least 12 hours and perhaps 24 hours after a pond has been dosed with PP.

Hanover Koi Farms
02-04-2006, 02:12 PM
PP is "reactive" (to one extent or another) until spent. Its not spent until there is no color of any kind...brown, Tea or otherwise! Let the reaction finish, totally and as stated above, do not reverse unless there is an emergency. By redosing to achieve the desired "reaction time", you are actually increasing the dosage.

I would challenge anyone to tell me at what point there is absolutely no hint of purple in brown water during a PP treatment. Using a simple Orp meter you can see that the ORP will increase beyond that of its initial reading for the initial dosing when redosed at the same measurement.

Steve
Explain "to one extent to another". The brown/tea coloring quite often is caused by the oxidation of the organics and not always that the PP is not spent. That brown or tea coloration will not do much to kill pathogens in most cases, this however is totally dependent on the pathogens involved, and many other factors.Besides and orp meter you can also determine the viability of PP using peroxide. Take two equal cups of the colored water, and add one drop of peroxide to one of the cups...how much the color changes in that cup as compared to the cup without it will give you a hint as to how spent the PP actually is as well.

Roddy Conrad
02-04-2006, 02:23 PM
"Most" of the brown color after PP treatment is an unstable form of PP that usually disappears overnight, or immediately if the peroxide is added. I looked up that chemistry once to understand the process. The wierd thing is that it shows as active chlorine in a chlorine test, even though it is a spent form of PP. Sodium thiosulfate does not get rid of it, but sodium thiosulfate deactivates the active real pink or purple potassium permanganate. Even though the brown unstable spent brown form of PP shows as active chlorine on a chlorine test, it does the fish no harm, and does not require reversal with hydrogen peroxide.

I realize this is pretty useless information for the average hobbyist, but may be an interesting sideline comment for John and Steve, since they are "into details".

schildkoi
02-04-2006, 02:25 PM
Redosing when not TOTALLY spent equals a higher reactivity level. My point was exactly as you stated John:


The brown/tea coloring quite often is caused by the oxidation of the organics and not always that the PP is not spent.

You are also correct that the reactivity level may be such at that point as to not be effective against pathogens...no issue. The issue is that redosing results in a higher ppm level of PP since some reactivity is still remain. To what extent is unknown at that point in time. Dealing with "unknowns" can be dangerous. Let the PP run its TOTAL coarse, then redose. I suggest on alternating days in fact. Typically this isn't even needed if the pond is maintained in a clean and healthy manner to begin with.

Steve

Noahsnana
02-04-2006, 02:26 PM
I am a fly on the wall...very interesting conversation :thinking:

stephen
02-04-2006, 02:30 PM
"Most" of the brown color after PP treatment is an unstable form of PP that usually disappears overnight, or immediately if the peroxide is added. I looked up that chemistry once to understand the process. The wierd thing is that it shows as active chlorine in a chlorine test, even though it is a spent form of PP. Sodium thiosulfate does not get rid of it, but sodium thiosulfate deactivates the active real pink or purple potassium permanganate. Even though the brown unstable spent brown form of PP shows as active chlorine on a chlorine test, it does the fish no harm, and does not require reversal with hydrogen peroxide.

I realize this is pretty useless information for the average hobbyist, but may be an interesting sideline comment for John and Steve, since they are "into details".
I see you followed up on my pp/chlorine test Roddy.:)

Roddy Conrad
02-04-2006, 02:38 PM
I see you followed up on my pp/chlorine test Roddy.:)

Precisely. I got the same result you did. It is a bit wierd, and the explanation above is only a partial explanation, even though it IS correct as far as I explained it. Also, as you said a few months ago, when the brown spent form of PP (or spent forms of ozone) are present, we get a positive test for chlorine as well as active chlorine, even though there is no active ozone, no active PP, and no active chlorine. There IS one or more unstable compounds that disappear in a day or so, which show up in either the active chlorine or total chlorine test procedures. But the unstable compound or compounds are not harmful to the fish.

Roddy Conrad
02-04-2006, 02:40 PM
Redosing when not TOTALLY spent equals a higher reactivity level. My point was exactly as you stated John:



You are also correct that the reactivity level may be such at that point as to not be effective against pathogens...no issue. The issue is that redosing results in a higher ppm level of PP since some reactivity is still remain. To what extent is unknown at that point in time. Dealing with "unknowns" can be dangerous. Let the PP run its TOTAL coarse, then redose. I suggest on alternating days in fact. Typically this isn't even needed if the pond is maintained in a clean and healthy manner to begin with.

Steve

I have redosed at 2 ppm dose level as many as 20 times in a single day IN A REALLY DIRTY POND while following the active level with a calibrated ORP meter. However, if you are depending on color alone to make the redose decision, and are not really well versed and experienced in PP treatments, then the advice you give is well taken for a newbie.

Noahsnana
02-04-2006, 02:43 PM
Just for the sake of it for others learning what are the ORP levels at desired pre during and post treatment.

Hanover Koi Farms
02-04-2006, 02:43 PM
Redosing when not TOTALLY spent equals a higher reactivity level. My point was exactly as you stated John:



You are also correct that the reactivity level may be such at that point as to not be effective against pathogens...no issue. The issue is that redosing results in a higher ppm level of PP since some reactivity is still remain. To what extent is unknown at that point in time. Dealing with "unknowns" can be dangerous. Let the PP run its TOTAL coarse, then redose. I suggest on alternating days in fact. Typically this isn't even needed if the pond is maintained in a clean and healthy manner to begin with.

Steve

Man, this is getting scary...I think we almost agree on something. Let me explain further.

How I do PP treatments is totally dependent on the pathogen I am dealing with, and the severity of infestation. Costia for example, is one that require a close eye, and a judgement call as for how often and whether I redose or not. I can say that in most cases I like to maintain pink or purple for 10 hours with this bug, and especially in cases where the fish are heavily slimed. I personally try to get rid of some of that slime with the initial dose so that the PP can get to the bugs. Heavy slime will inhibit all treatments from getting to the bugs. Sometimes this can be accomplished with multiple and consecutive doses, and sometimes you can choose a heavier dose to get faster results. This is not something for someone to attempt that has little experience with PP. I very seldom even suggest a novice use PP.

Because of how Costia reproduce so quickly, there are times that we need an aggressive approach to stop them. There are many ways to utilize PP in treating fish, but I would highly suggest you start slow and low. It is always best to be conservative when it comes to this comp[ound, but you must also be aware that Costia can overcome and kill fish rapidly, and we may be forced to be aggressive. As I have said, Roarck has some very good and detailed articles on its use, and in general, you can see the many ways of utilizing it there.
So, in general Steve, I agree with what you say, I am just saying as well, that there are times that we need to give them a quick one two punch. This is however DANGEROUS for sure.

Hanover Koi Farms
02-04-2006, 02:47 PM
Oh, I forgot to mention that at the times I do redose in the same day, it is a lower dosage than the initial one for sure. I agree as well, that you are adding to the PPM if the color is still there. Read Roarks stuff, and I pretty much agree with his thinking on its use.

stephen
02-04-2006, 02:53 PM
Related thread when I treated for costia http://www.koiphen.com/forums/showthread.php?t=10961&page=1&pp=10

Noahsnana
02-04-2006, 03:11 PM
Talk ORP Stephen :thinking:

Roddy Conrad
02-04-2006, 05:21 PM
ORP measurement can be a useful tool for lots of purposes, but deciding whether you are at 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, or higher level PP dose is not one of ORP measurements best purposes.

The problem is that the ORP response gets flat with more PP at higher dose levels, plus the pH value has a huge effect on the response of ORP readings to PP dose levels. Some work I did in my basement at Camp Conrad given in the chart below gives examples of these issues.

schildkoi
02-04-2006, 07:20 PM
I think ya'll are coming around?

I get real concerned when I see certain types of statements, and yes, take them to task since many reading these threads only pick up on parts of things. In about 6 months time, we will see someone say that "Roddey dosed his pond 20 times in 1 day at 2 ppm PP."

I kinda doubt that Roddy did that but more than likely started at 2 ppm and redosed to maintain a stable Orp reading. Even if he stayed up for 24 hours straight making the purple Kool Aid, that's almost once an hour and the dosing would surely have gone above 2 ppm. In short, dosing 20 times to maintain 2 ppm is different than dosing 20 times at 2 ppm!

Steve

Roddy Conrad
02-04-2006, 07:34 PM
I think ya'll are coming around?

I get real concerned when I see certain types of statements, and yes, take them to task since many reading these threads only pick up on parts of things. In about 6 months time, we will see someone say that "Roddey dosed his pond 20 times in 1 day at 2 ppm PP."

I kinda doubt that Roddy did that but more than likely started at 2 ppm and redosed to maintain a stable Orp reading. Even if he stayed up for 24 hours straight making the purple Kool Aid, that's almost once an hour and the dosing would surely have gone above 2 ppm. In short, dosing 20 times to maintain 2 ppm is different than dosing 20 times at 2 ppm!

Steve

Okay, let's be very specific. It was a 1000 gallon water garden pond full of potted lilies and Sarassa comets. Over the winter, plant decay and stuff had accumlated on the bottom of the pond. I was afraid to "muck it out" of the junk because I was afraid I would stir up too much hydrogen sulfide and kill the Sarassa comets. I didn't even want to remove the Sarassa comets for fear of stirring up hydrogen sulfide by the act of trying to net the large stocking of adult Sarassa comets.

So I decided to get rid of any hydrogen sulfide by oxidizing it with PP before doing routine spring pond maintenance. I checked calibration of an ORP meter that I could plug in and read continuously. I put a set of air stones on a large air pump, turned off the biofilter system, and started "boiling up" the pond while watching the ORP meter and dosing it with PP. I would add a full 2 ppm dose, watch the ORP reading immmediately increase, then watch the ORP reading drop as the muck and potted plants consumed the PP dose. And, YES, I added 20 consecutive full 2 ppm PP doses in about 4 hours of dosing it while I was doing other pond maintenance activity while the PP cleanup of that pond continued. The next PP dose was not added until the ORP reading dropped below 450, and the purple/pink coloration had dropped to non visual levels.

The fish did great through it.

The next day I did the exact same thing in the pond immediately adjacent, namely another 1000 gallon water garden, full of lotus and golden orfes. Worked swell for it, too.

Since then, I don't let the hydrogen sulfide get to problem levels, and instead of that rather wild PP cleanup technique, simply remove all the potted plants, then start pumping out all the water removing all the fish to portable tanks sitting beside the pond. That is a bit faster than taking the time to add all that PP.

But for ponds with a noticeable hydrogen sulfide odor, what I did those two days are the safest way to clean up the pond without killing the fish.

The PP kills the hydrogen sulfide.

Koi Story
02-04-2006, 09:34 PM
Fish cannot live in a pond with a noticeable hydrogen sulfide odor; the pH would have to be too low (~5) and / or the H2S concentration too high.

ks

Bill OTMS
02-04-2006, 09:37 PM
Like others say, if there is pink or purple color, the PP is still active, and if there is no trace of pink of a sample taken in a white 5 gallon bucket, you know it is gone.
Also, in general, an ORP reading above 400 indicates residual active PP.
As a sideline to this discussion, a test for chlorine after a PP dose shows active chlorine when there is none, since the chlorine test simply indicates whether an active oxidizer is present or not. Also, for about 12 hours after the PP is spent or reversed, the chlorine test will give a positive reading even though the PP is completely spent or reversed. The point is a chlorine test is meaningless for at least 12 hours and perhaps 24 hours after a pond has been dosed with PP.

Now, that's good to know. Thanks, R.

Oh, yea. Just coming into the thread.

schildkoi
02-05-2006, 01:42 PM
I didn't know that a gas such as Hydrogen Sulfide could be oxidized. So i did a little reading up and found out that you were absolutely correct! But, I am sure glad you are a chemist because the literature I read says that it can be unpredictable and dangerous!


Potassium Permanganate

Potassium permanganate is a strong oxidizing agent that can react with hydrogen sulfide in a variety of ways, depending on whether the stream is acidic or alkaline. In acidic conditions, the following reaction takes place:

Pic 1 below









Under alkaline conditions the following takes place:

Pic 2 below





Under conditions that are in between acidic and alkaline pHs, a variety of reactions occur, yielding elemental sulfur, sulfate, thionates, dithionates and manganese sulfide end products. Potassium permanganate has been fairly effective when added to the sludge dewatering operation, where it is added to the suction side of the sludge pumps feeding the dewatering unit.



Disadvantages: Dosages are difficult to predict and control in most liquid applications. The high cost and high dose, 6 or 7 parts of potassium permanganate are needed for each part of hydrogen sulfide, are discouraging. Safety precautions are required for handling and storage.


Based on this, it wouldn't seem that 2 ppm of PP would be effective in this process. Perhaps the Hydrogen sulfide was off gassed due to the airation you set up instead?

Steve

Noahsnana
02-05-2006, 02:36 PM
What did he say :thinking:

Roddy Conrad
02-05-2006, 04:05 PM
Steve said that the oxidation of hydrogen sulfide requires a ratio of potassium permanganate 6 to 7 times the hydrogen sulfide to be effective at the oxidation. Since the odor of hydrogen sulfide is detectable at values as low as 0.01 ppm, adding 2 ppm PP gives a ratio of 200, which is many times the minimum level to oxidize it.

So Steve verified by checking up on me that this old chemist was taking care of his fish by making sure any hydrogen sulfide in the muck was oxidized to safe sulfate ions before I cleaned out my water gardens in the Spring.

Like I said before, I only did this once, when it was obvious I had a serious water quality problem from a faint odor of hydrogen sulfide when I started to clean it up. I stopped in my tracks, set up the PP, and oxidized it quickly with those twenty sequential 2 ppm PP treatments before continuing to clean up the pond to get it ready for the summer ponding season.

Glad to see Steve is trained in looking up chemical reactions!

Noahsnana
02-05-2006, 04:09 PM
okay am i right the 2ppm is the dosage for cleaning not bug zapping

schildkoi
02-05-2006, 04:15 PM
You said:


Steve said that the oxidation of hydrogen sulfide requires a ratio of potassium permanganate 6 to 7 times the hydrogen sulfide to be effective at the oxidation. Since the odor of hydrogen sulfide is detectable at values as low as 0.01 ppm, adding 2 ppm PP gives a ratio of 200, which is many times the minimum level to oxidize it.

That is NOT what I said. You infer that you only had .01 ppm Hydrogen sulfide. How did you know? I said that you were more likely degassing through the airation. In addition, you were most probably stirring up all of that muck with the airation.

Noahsnana, In a clean pond, 1.5 ppm PP does the trick. Dose every other day for 2 doses. Gets Costia and Trich, Deep rooted Costia may require additional and varying treatments but this is the abnorm (1 in 100 cases). Some people use higher concentrations...usually due tro not having a clean system to start with.

Steve

Noahsnana
02-05-2006, 05:28 PM
Noahsnana, In a clean pond, 1.5 ppm PP does the trick. Dose every other day for 2 doses. Gets Costia and Trich, Deep rooted Costia may require additional and varying treatments but this is the abnorm (1 in 100 cases). Some people use higher concentrations...usually due tro not having a clean system to start with.

Steve
I understand :thumbsup:

Roark
02-05-2006, 09:56 PM
Steve;

The formula's you posted are just two of them. I can name three more routes to end products using KMnO4 and H2S as the inputs. And it needs to be realized that all of the formulas you posted are EMPIRICAL and GENERAL in nature and reflect neither equilibrium effects, or time, redox levels, trace metals nor the catalytic effects of the manganate byproducts being produced. Essentially there aren't any hard and fast answers so the blanket statement that it takes 6 to 7 times the amount of H2S isn't accurate. You can actually get places rather quickly with anywhere from 2 to 25x the amount of H2S.

No flame... just correcting a few assumptions. :)

Roark

Roddy Conrad
02-05-2006, 10:02 PM
Any time the water develops a bad odor on any of my ponds and aquariums, out comes the PP and very soon my nose is very pleased at the absence of odor.

Now when Lizzie puts on her favorite perfume, Sung by Alfred Sung, I leave the purple cloud "in the can", and enjoy the smell!

We can write lots of pretty chemical equations, but my nose leads the way on this issue.

schildkoi
02-05-2006, 10:40 PM
My point is that the Hydrongen sulfide is trapped in the muck and very little releases when undisturbed. When disturbed I am betting is far above that .01 ppm youo quoted and thus the previous post of mine is even more applicable.

Steve

Graham
02-05-2006, 11:26 PM
Any time the water develops a bad odor on any of my ponds and aquariums, out comes the PP and very soon my nose is very pleased at the absence of odor.

Roddy...please...... if your ponds are getting to the point that you can smell them then please give up this hobby and go back to stamp collecting....you should never be able to smell your pond or an aquarium. You're falling down on the job!!!

Can you imagine when I had 80+ aquariums in my parents basement...probably 1800+ gallons of water if they could smell H2S or methane or dead algae or that general bad aquarium smell that comes with bad husbandry...I would have been living on the street............Please learn some husbandry for ornamental fish

Alfred Sung, a Canadian btw...wouldn't cover that smell

G

Roark
02-05-2006, 11:37 PM
Steve, your numbers are a bit skewed. This stuff makes for good reading, so I'll post it as a general addition to your reading list:

- The lower odor detection limit (human, 50%, B=1.3) for H2S is 0.01 ppm to 0.047 ppm, (depending on the reference, with 0.01 ppm being OHSA's number and the higher number being from the Bureau of Mines, each of which tends to have some rather well-documented differences in opinion due to their obvious polarizations).

- Goldfish (Carassius auratus) showed "observed stress" after a 96 hour exposure to 10,000 ug/L [Bull.Bur.Fish.No.22, U.S.Dep.Commerce]

- Bluegill (Lepomis macrochirus) showed only a perceptible reduction in growth after a 200 day exposure to 1.5 ug/L [Chronic Effects of Low Levels of Hydrogen Sulfide on Freshwater Fish, Smith, L.L.J., and D.M. Oseid, 1975, Prog.Water Technol. 7(3/4):at 599-605]

- Even Rainbow Trout fry (Oncorhynchus mykiss) which are routinely used as a rather fragile "benchmark" species in chemical testing managed to survive 24 ug/L for 72 hours [Effects of Hydrogen Sulfide on Fish Eggs and Fry, Smith, L.L., and D.M. Oseid, 1972, Water Res. 6(6):at 711-720]

So while its clear that H2S is not a good thing, the truth is you can often detect it before it kills fish. Lord knows I've been to plenty of ponds where the water stank to high heaven and the fish, while not particularly happy, were still swimming. And eating. And would have throttled the pond owner if they had fingers and AK-47's with a banana clip. :)

Put another way: If H2S was indeed toxic at the lower limits of human detection, AquaScapes would be bankrupt. hehehehe. :)

Again... no flames... just data.

Roark

Koi Story
02-05-2006, 11:52 PM
Since the odor of hydrogen sulfide is detectable at values as low as 0.01 ppm,
Like I said before, I only did this once, when it was obvious I had a serious water quality problem from a faint odor of hydrogen sulfide when I started to clean it up. QUOTE]

[QUOTE=Roark] - The lower odor detection limit (human, 50%, B=1.3) for H2S is 0.01 ppm to 0.047 ppm, (depending on the reference, with 0.01 ppm being OHSA's number and the higher number being from the Bureau of Mines, each of which tends to have some rather well-documented differences in opinion due to their obvious polarizations).

Roark


Does this mean that 0.01 ppm of H2S dissolved in water can be detected by smell?
At what pH?

ks

Roddy Conrad
02-06-2006, 06:56 AM
Roark's references and mine on the odor threshold of hydrogen sulfide are different. The hydrogen sulfide odor threshold varies from person to person from 0.001 ppm to 0.13 ppm in the references I found on the subject.

I have had hydrogen sulfide detectable odors in my ponds and aquariums without any obvious adverse health symptoms of the fish. Since the values measured for fish health from hydrogen sulfide is very low as given below, I assume my personal odor threshold is fairly low, since it varies from person to person over such a huge range.

TLM = Threshold Limit Value for death for the type of fish in water with this much hydrogen sulfide:
TLm (Lepomis macrochirus, bluegill sunfish) 96 hours = 0.0448 mg/L
at 21-22 deg C
TLm (Pimephlaes promelas, fathead minnow) 96 hours = 0.0071-0.55
mg/L
TLm (Salvenilis foninalis, brook trout) 96 hours = 0.0216-0.038 mg/L at
8-12.5 deg C

schildkoi
02-06-2006, 10:31 AM
From Roddy's and Roarks post, it would seem that Hydrogen sulfide is a non issue in a pond since you can "smell" it before it gets to a lethal level and that these low levels are such that 20, 2 ppm PP in 4 hours is more than enough to handle what hydrogen sulfide there may be.

But now for the confusing part. How do Koi ever die from these levels (and they do die from Hydrogen sulfide poisoning)? Could it actually be that these levels can actually be much higher? Could it actually be that this gas is trapped in the muck at the bottom of the pond? Could it go undected until such time and this muck is disturbed? Could it be that TWA (time waited average) levels have little to do with it and that lethal levels can be triggered in a very short period of time? Could it also be that hydrogen sulfide could be in the total gas saturation measurement of the pond as well (at non lethal levels until muck is disturbed)?

Final point:
I think using PP as a pond cleaner is a very dangerous practice....short term or long term, take your pick and for a vast variety of reasons. 20, 2 ppm PP doses in 4 hours is, for lack of a better term, a very dumb practice, especially for typical hobbyists. Even at those rates the ability to use PP to clean the pond thoroughly (including all the muck in a "very dirty pond") is doubtful at best and the remaining "left overs" would still require removal (as well as the Koi during the cleaning).
Steve

Koi Story
02-06-2006, 03:16 PM
"Roark's references and mine on the odor threshold of hydrogen sulfide are different. The hydrogen sulfide odor threshold varies from person to person from 0.001 ppm to 0.13 ppm in the references I found on the subject". Roddy Conrad

If this is about H2S dissolved in water a pH and a temperature have to be specified, because H2S ionizes in water. At a pH of 8 and at 77 F, 100% of the H2S is ionized (1)--not in gas form--and it cannot be smelled (neither degassed). Could you please post the reference?
(1) The Nalco Water Handbook. Nalco Chemical Co., Frank N. Kemmer editor. Page 14.5, fig. 14.6.

The following is from: http://aquanic.org/publicat/state/il-in/as-503.htm#Water's%20Chemical%20Factors (a link posted by HanoverKoiFarms)

Appendix 1
TABLE 3 Suggested water-quality criteria for aquaculture hatcheries or production facilities. Salmonid quality standards with modification for warm water situations. Concentrations are in ppm (mg/L). (Source: Modification from Wedemeyer, 1977; Piper, etc al. (Larsen), 1982)
Chemical Upper Limits for Continuous Exposure and/or Tolerance Ranges
Hydrogen sulfide 0.002 ppm (Larsen - 0.0 ppm)

ks

Roddy Conrad
02-06-2006, 07:06 PM
Hey, you can post as much stuff as you want about this subject, it does not change the essentials.

Those are:

1. If you have potted plants in your pond, or rocks at the bottom of your pond, or gravel at the bottom of an aquarium, or you don't clean the pond bottom often enough, you will develop some hydrogen sulfide in these described situations. Disturb the hydrogen sulfide, and I guarantee you it will be detected by your nose! And it is not a good thing, we all agree about that!

2. If you have some hydrogen sulfide, there is no doubt it is easily oxidized by potassium permanganate, in theory or practice. I described doing it in practice, Childers didn't like it much, okay, I agreed it is better to maintain your pond in a way that the hydrogen sulfide does not become detectable, and you don't need to react it away with PP. But there are still some readers of this board with Aquascapes ponds with rock bottoms, or a bunch of potted plants, so I thought maybe some of them might want a clue how to deal with emergency situations involving hydrogen sulfide in their ponds and pond water.

2. Since we have folks "demanding sources", here is a direct quote from that set of books with the name "Encyclopedia of Chemical Technology" which sit handy on my shelves both at work and at home and get used regularly: "Hydrogen sulfide is readily oxidized by many oxidizing agents. The oxidation products depend on the oxidizing agent, its concentration, its molal ratio to the hydrogen sulfide, and the conditions of the reaction." A table is presented which shows, for example, hydrogen peroxide oxidizes hydrogen sulfide to sulfur at a neutral pH, and to sulfate at an alkaline pH.

3. Hydrogen sulfide CAN exist in pond water for sure! There is no doubt about that! Aqueous solutions of hydrogen sulfide are weakly acidic. Hydrogen sulfide will react with sodium carbonate at a pH of 10 to 11 to make NaHCO3 (baking soda) and NaHS, but it won't react with NaHCO3 (sodium bicarbonate or baking soda) at normal pond pH ranges.

4. My main source for the odor threshold and fish toxicity values come from primary MSDS (material safety datasheet) information for hydrogen sulfide. I could trace that information back to original source if I wanted, but I don't wantta, it is a pleasant hobby after all for me, not an obsession.

5. You are better off managing your ponds and aquariums so they don't develop a detectable (by your nose) hydrogen sulfide odor. We run 9 ponds and 9 aquariums as a hobby, sometimes I don't do the maintenance of every pond and every aquarium on my preferred schedule, since at age 64 I still work a 50 to 60 hour work week at a demanding technical job, and plan to continue doing so for many years more. When I smell the stuff, I take care of it with PP quickly. You do it any way you want. But if you start stirring up the hydrogen sulfide pockets with fish present, without oxidizing it first with PP, you are very likely to have a pond or aquarium full of dead fish in a hurry.

And, hey, flame away, I am used to it.

Graham
02-06-2006, 08:07 PM
Roddy I could pic away at the above post but but I won't....I think that what we are all kind of saying here is lets teach ponders the right way, the correct way........that's not to let things in your pond, be it a Koi pond or an AS pond, or an aquarium, get to the point where toxic gases are being produced...That is just poor husbandry.


Yes they show up in plant pots and under some coping rock but they are not supposed to show up from crap build up. Especially at a point where a ponder ia afraid to touch the silt or has to use oxidizing chemicals to neutralize them.

If a person can't maintain the system so that doesn't happen then they need to change things.......I'd love to have 80 tanks again and be breeding Discus, Angels, Oscars, Jacks and little SA's again but I know that I could never maintain them now so I don't have them. Maybe you should look at selling off some of those tanks

G

Koi Story
02-06-2006, 09:08 PM
4. (...) I could trace that information back to original source if I wanted, but I don't wantta, (...)

And, hey, flame away, I am used to it.

The above statement should have sufficed.

[the post was intended], not to contradict and confute, nor to believe and take for granted, nor to find talk and discourse, but to weight and consider. Lord Bacon

Thanks anyway,

ks

Roark
02-07-2006, 12:05 AM
In re-reading this whole thing, the smart ponder will note a few things:

1). H2S isn't a good thing at any level. We can squabble all we want about the actual levels, but ANY detectable H2S is a problem which requires some changes to our husbandry protocols. Once you've got H2S in the system, it's time to stop benchracing and start FIXING the problem.

2). If you do detect H2S, the sensible thing to do is add KMnO4 sufficient to buy you some time while you remove the fish, address the problem, and get rid of the offending anaerobic layer producing the problem.

3). H2S likes to form in, and be trapped by, anaerobic gunk on the bottom of a dirty pond. No gunk = no H2S. If you've got bottom drains and are careful about keeping the pond clean, this entire discussion is largely of an academic nature. If you've got a cesspool with fish thrown-in, then stirring-up the bottom-gunk is a singularly effective way to kill fish by the score.

4). Different people can (and will) use different approaches in any given pond management scenario. Folks like Steve Childers shouldn't be trusted with anything more dangerous than a frog-target and a squirt-gun. (Notice tongue planted firmly in cheek here). Guys like Roddy can get by using an atom-smasher, a piece of duct tape and a rolled-up newpaper. In the end, most of us common-folk will fall between these two extremes.

My 2 cents worth. :) YMMV. :)

Roark

Ruth
02-07-2006, 12:38 AM
Best thing we ever did was #3 Roark. We had a flat bottom pond with no drain and it collected stuff like crazy. On the redo we sloped the the bottom to a drain and added a sort of tpr. Now we don't have to clean the pond :cool: ...just the filters! :yes: