Sodium percarbonate uses in fish ponds

[Roddy Conrad]

The filters were on, and had been on all Winter, and are oversized for the load, in both of the ponds where I have been using sodium percarbonate to clean the pond and kill the algae.

Certainly sodium percarbonate should NOT be used in a pond with no circulation or filter system.

I don't like the stringy algae. It is ugly, and makes a pond ugly, and the purpose of the pond is to be something lovely and relaxing in my yard. So out will come the sodium percarbonate if I have a serious string algae problem.

I used PP (potassium permanganate) the same way in the past, and still use PP to clean up the water since it is significantly less expensive for that purpose than sodium percarbonate. But sodium percarbonate is my choice for a pond with stringy algae or a lot of yuck that needs cleaning up.

Others can do it all kinds of ways that please them in their hobby, it is okay with me.

Diane, I have not had any green water to treat with the sodium percarbonate, but would expect it to easily kill green water algae.

[Susan]

Will sodium percarbonate or PP eliminate the brown coloring from tanins in the water?

[Roddy Conrad]

Sodium percarbonate clears up the brown color in tanins in the water. So, YES, it does that.

PP will also clear tanins from the water in some circumstances, but sodium percarbonate will be more efficient at that particular problem.

[luke-gr]

Sodium percarbonate clears up the brown color in tanins in the water. So, YES, it does that.

PP will also clear tanins from the water in some circumstances, but sodium percarbonate will be more efficient at that particular problem.

Good to know. Roddy, care to elaborate on WHY the SP is better than PP in clearing up tannins?

[Roddy Conrad]

Good to know. Roddy, care to elaborate on WHY the SP is better than PP in clearing up tannins?

Because the sodium percarbonate is safe to dose at a higher oxidizer level than PP, and because sodium percarbonate is a bleaching agent from the hydrogen peroxide content that removes brown color from water.

I saw the tanins completely disappear in a few days in the treatment of our two water gardens last week, and the starting color of the water was dark brown from tanins. PP does not work that fast or that efficiently on tanin content of the water. To get rid of the tanins with PP takes much longer and is more dangerous to the fish in the water.

[Lee B]

The dose rate again?

2 lbs. per 1,000 gallons for the initial dose, and 2-3 Tbs. per week for maintenance?

[Roddy Conrad]

Please remember the LC50 information near the start of this thread:

The LC50 (dose at which 50% of the fish die if the dose remains active for two days and has nothing to react it away) of sodium percarbonate is 0.6 pounds per 1000 gallons. If there is something there like stringy algae or bottom yuck in the pond the hydrogen peroxide will be all gone in a few hours, so I indeed dosed my dirty water garden ponds with an initial dose of a pound per 1000 gallons, then used another pound per 1000 gallons the rest of the week to complete the cleanup.

Don't use a pound per 1000 gallons in a relatively clean pond, it would be too much.

If the brown color isn't gone, there is still stuff to consume the sodium percarbonate and its reaction product hydrogen peroxide.

Over on a stringy algae thread on KoiVet, someone asked me the good question of why not just use hydrogen peroxide itself? The answer is that if you buy the 3% hydrogen peroxide at Walmart in the hair care isle for this purpose, you are paying 5 time as much for the active hydrogen peroxide as you pay for the active hydrogen peroxide content in sodium peroxide, and you would need 4 gallons (16 of the one quart bottles at Walmart) of 3% hydrogen peroxide to be equivalent to the hydrogen peroxide content in a single 2 pound bottle of sodium percarbonate. And that is why it is so effective..........

[GloriaL]

Roddy, it seems I remember reading on some thread that adding H2O2 to stop the PP reaction would seriously lower your orp and could be bad for your fish. Does using the sodium percarbonate have that sort of effect on the orp?

[Roddy Conrad]

I dropped 168 grams (1.5 cups) of sodium percarbonate into our 4000 gallon indoor koi pond today to see the effect on ORP reading, since I have two on line calibrated ORP meters on that pond. The reading dropped immediately with the sodium percarbonate addition from 300 to 140, then the reading started slowly climbing back up, and is up to 210 in about a hour.

The drop of ORP with hydrogen peroxide reversal of PP is similarly abrupt, then the next day the ORP is back up to the normal value. The issue with using peroxide to reverse active PP is the sudden shock of such large changes in the oxidation state. Adding sodium percarbonate to water that has no active PP will not be as abrupt a change.

The effect of hydrogen peroxide (and/or sodium percarbonate) on ORP is a strange effect. I need to read up on oxidation potential technology some more to understand it.

[GloriaL]

Thanks for the experiment and the info. How long did it take to go back up?

[Roddy Conrad]

I got the following questions privately and decided to answer them publically:

1. PP does it actually oxidize nitrates?

Roddy: Actually, I don't know whether PP does or does not oxidize nitrates. This is not the first time someone has asked that question. I need to set up a controlled experiment to answer that specific question. My answer today is simply that I don't know whether PP does or does not oxidize nitrates.

2. Okay my system is up and running pond size is 1920 gallons. I use 1.2 pounds of SP. Does that get the crud on the bottom of the pond too?

Roddy: The sodium percarbonate will get the crud on the bottom of the pond if you use enough of it to do the job. How much will depend on the thickness of the layer of crud and how much other stuff you need oxidized by the hydrogen peroxide.

3. Does the SP do oxidize as well as the low level pp? Do I need to do both, or just use the SP when there is String Algae?

Roddy: I have not used the sodium percarbonate long enough to know whether it oxidizes pheromones, the antigrowth regulator. I don't know yet whether sodium percarbonate is or is not a good replacement for regular low level PP treatment and all the things it does for pond maintenance. Certainly the sodium percarbonate does many of the same things as low level PP treatment, and certainly it is safer for the fish, and it is pretty cheap to buy (like PP which is also cheap when bought in the right places).

4. Will the SP work on an algae bloom, or pea green soup. I have a friend who can't keep his pond clear.

Roddy: Sodium percarbonate should kill pea green soup algae as well as string algae. I never get pea green soup algae, so can't give you a first hand account of that use. Even my crudest filter system always keeps pea green soup algae under control with my other practices.

Gloria, the ORP of the indoor koi pond data today:

ORP reading before adding anything: 300 - this is a well maintained pond indoors with a huge filtration system that stays at high water quality every day of the year.

ORP reading right after dumping in 1.5 cups sodium percarbonate: 130 to 140

ORP reading an hour later: 210

ORP reading 3 hours later: 260 - I expect the reading to be at 300 again tomorrow morning as usual after hydrogen peroxide "does its thing".

[Rich L]

Well here goes another wave of battles!

Nice going Roddy, no matter whether it will ever be picked up as a suitable alternative for high quality koi ponds, there is a huge need for the 'Aquascapes' level of ponds.

Garrett (Harvy The Koi) made a point I need to support. There is no substitute for a properly designed and maintained pond. If you are experiencing a serious green water or string algae problem every year, the pond is either poorly designed of isn't being properly maintained. The problem with continuing to kill what may be a symptom, leaving other problems to harm the pond environment, is too easy here.

I know many old ponds that have had the UV fixtures permanently turned off because the filters and proper maintenance have led to a pond that doesnt turn green or develop string algae. Roddy is able to work beyond the edge of practicable pond conditions because of his unique background and willingness to keep close track of the conditions he creates. Even so, you won't see the conditions he posted earlier in his main ponds. He's different from us.

I will be using this product on poorly designed ponds but I will still try to encourage the owners to fix their problems rather than fall back on any product.

[Rich L]

Assuming a maintenance dose of two tbs/1000/wk, how much buffering capacity should we expect from it. Will you still use the SC as you have for buffering?

[Valentina]

I don't have string algae, but just lots of tannins from leaves. I also don't have fish in this pond (it's new, no fish yet). My question is... how much sodium percarbonate I should use to get rid of the tannins? There are no more leaves in the water (I think I got them all) but the water is, of course, pretty dark.
How much would I have to wait, after I use the sodium percarbonate, before I can add fish? I understand the sodium percarbonate is safe with fish, but just in case I add a lot... how long is the sodium percarbonate active?
Thank you.


Valentina

[ponderingkoi]

Thanks for all your input Roddy...we appreciate it! I too battled some string algae last summer, but it was my first summer with fish...so we'll see how things settle in this year. Always had clear water (w/UV's running) and spot-on water parameters...but I sit in full sun and the string algae loves my long waterfall. I've got a good stock of the SP and hope to be enjoying the pond more and harvesting less string algae. Paula

[Roddy Conrad]

I don't have a string algae problem in our "proper koi ponds", but certainly have it in our two water garden ponds at this time of year if I don't use chemicals to control it. And I don't plan to use sodium percarbonate in our ponds that have no need for it!

So I have no argument that a properly designed and maintained koi pond won't need sodium percarbonate to clean it up. And In My Opinion that means about 99.9% of the decorative fish ponds out there can use the sodium percarbonate (since they AREN'T proper koi ponds!), and certainly the Aquascapes rock bottom ponds can use sodium percarbonate the most!

[Roddy Conrad]

Assuming a maintenance dose of two tbs/1000/wk, how much buffering capacity should we expect from it. Will you still use the SC as you have for buffering?

The reaction of hydrogen peroxide with DOC is expected to produce acid as shown below:

H2O2 (hydrogen peroxide) + CH3CH2CH2 (and so on) --> H2CO3 (carbonic acid or dissolved carbon dioxide) + H2O

So each H2O2 is expected to create a half mole of acid

Na2CO3 + H2CO3 ---> 2NaHCO3 or baking soda

So the mix of hydrogen peroxide and sodium carbonate from the hydrolysis of sodium percarbonate is expected to generate good old baking soda as additional pond buffer.

Expect each pound per 1000 gallons of sodium percarbonate to generate about 70 ppm additional total alkalinity or KH.

[Roddy Conrad]

I don't have string algae, but just lots of tannins from leaves. I also don't have fish in this pond (it's new, no fish yet). My question is... how much sodium percarbonate I should use to get rid of the tannins? There are no more leaves in the water (I think I got them all) but the water is, of course, pretty dark.
How much would I have to wait, after I use the sodium percarbonate, before I can add fish? I understand the sodium percarbonate is safe with fish, but just in case I add a lot... how long is the sodium percarbonate active?
Thank you.


Valentina

Use enough to get rid of the brown color in the water.

Then wait two days for all the hydrogen peroxide from the hydrolysis of the sodium percarbonate to be used up before adding fish in case you overdosed it.

[Rich L]

The reaction of hydrogen peroxide with DOC is expected to produce acid as shown below:

H2O2 (hydrogen peroxide) + CH3CH2CH2 (and so on) --> H2CO3 (carbonic acid or dissolved carbon dioxide) + H2O

So each H2O2 is expected to create a half mole of acid

Na2CO3 + H2CO3 ---> 2NaHCO3 or baking soda

So the mix of hydrogen peroxide and sodium carbonate from the hydrolysis of sodium percarbonate is expected to generate good old baking soda as additional pond buffer.

Expect each pound per 1000 gallons of sodium percarbonate to generate about 70 ppm additional total alkalinity or KH.

Does that mean that Sodium Chloride converts to Baking Soda? Most of the folks that put down Baking Soda in the pond seem to be selling Sodium Chloride as a product that stays in the pond longer.

[Roddy Conrad]

Sodium chloride stays sodium chloride. Sodium chloride will not convert to baking soda.