Koi Toilet 1 4” bottom drain broke

[Leecm3]

Hello, hoping for some advice on repairing my bottom drain. The bottom drain is a koi toilet 1 with air diffuser. It was been installed for about 2 years with no issues.

Yesterday went to check on pond and saw air diffuser floating on top of water and air billowing out of bottom drain where air line comes into bottom drain. Not losing any water. Not sure what happened I have not been in pond since pond build and no rocks or plants in pond. Just broke of at stem that is attached on bottom of bottom drain. I live in southeast Virginia and although cold temps have been staying above freezing.

I am still running filter keeping my fingers crossed no fish get sucked up. All fish are 8” or larger. I have a zakki sieve before pump. All filtration including air pump is well above water line so not worried about water back flowing into air pump. Plus air pump manifold valve feeding bottom drain is turned off.

Was thinking of draining pond down to 2 feet (4.5 feet is current depth) and either use a fernco fitting to attach the air diffuser center column to bottom drain or Use a 1” pvc pipe as a coupler and use pvc glue to attach the center column to the bottom drain. Not comfortable with using pvc glue underwater let alone in in 40 degree water. Any advise or suggestions?

Here a few pics of center column showing were pipe broke.




Here are a few pics of bottom drain using underwater camera were pipe broke

[*Ci*]

I don’t have and advice for fixing, but I would throw some kind of grate over the exposed BD pipe. Even a large fish can get sucked in or against it. Big koi get stuck in skimmers all the time. An upside down milk crate with a brick on top would work - something like that.

[Leecm3]

I don’t have and advice for fixing, but I would throw some kind of grate over the exposed BD pipe. Even a large fish can get sucked in or against it. Big koi get stuck in skimmers all the time. An upside down milk crate with a brick on top would work - something like that.

Good call, I put some egg crate material like what’s used for lighting over bottom drain opening with a brick zip tied to secure brick. All fish accounted for so nobody got sucked into 4” line.

[catfish whiskers]

Unfortunately, that part of the air stem in the koi toilet is very thin and it’s weakest point . Luckily it doesn’t leak , so that’s a good thing . The only way I can think to reattach the stem , would be to use an internal pipe coupling like this
https://www.supplyhouse.com/Spears-S...ipe-I-D-Spigot
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You would have to drain the pond and glue it in , but I would not recommend the internal coupling to reattach the stem and dome , because of the thin weak area there , and a future issue might break it further causing a need for a complete bottom drain replacement .
I think Your only recourse here would be to use a bottom drain cover with a diffuser , either DIY , or Sacramento Koi makes one .
https://sacramentokoi.com/advantage-...-air-diffuser/
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Here’s pics of the ones I make using a large bowl shaped plastic flower pot as a mold .




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What You cannot see , is the internal fittings within the concrete, and all flush fittings are threaded including the sockets for the three tripod legs . Making the threaded sockets for the legs , allows for easily changing the BD cover gap by changing the legs .
You would have to run a new external airline to use a cover , but if the pond was ever drained someday , You could use the previous mentioned internal coupling to attach a fitting and flexible air hose to feed the cover. Please feel free to ask if You need more info .

[Leecm3]

I would prefer not to have to run an external air line if I can avoid it.

So you think if I use a fernco fitting to attach center column to bottom drain that it may overtime damage the bottom drain?

I would cut the existing center column to add threaded couplings then attach the bottom portion of center column to base using fernco fitting then attach the upper portion with bottom drain cover and air diffuser by screwing the couplings together.

[batman]

Is the drain base actually damaged or just broken off pipe threads in collar? If broken off pipe use a inside pipe extractor.

[Leecm3]

It’s broken off, base not damaged. I was also thinking of pipe extractor tool wasn’t sure of risk of cracking the base while trying to back out broken piece of pvc. I like the idea of using pipe extractor.

[jcardona1]

I've said it before and I'll say it again, do not waste your money on the Koi Toilet! Very poor construction, makes me nervous to have it at the bottom of my pond buried in concrete. Rhino drains might cost more but they're built like tanks.

Sent from my SM-G973U using Tapatalk

[batman]

It’s broken off, base not damaged. I was also thinking of pipe extractor tool wasn’t sure of risk of cracking the base while trying to back out broken piece of pvc. I like the idea of using pipe extractor.

You are very fortunate it didn't crack out at the base. I think there are threads on Koiphen where people successfully extracted the broken part.

Edit: Here's two

https://www.koiphen.com/forums/showt...-my-Koi-Toilet

https://www.koiphen.com/forums/showt...stem-broke-off

[catfish whiskers]

From the part circled in red , it looks like a part of the bottom drain itself broke off , and not just the threaded riser .
.

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If that pic is merely a coupling You added , and it was the bottom of the threaded riser that broke off , simply remove the broke threaded piece like mentioned, and make a new one .

[batman]

Maybe it's something like this socket to MPT fitting. I'd replace with all schedule 80 stem vs 40. Since others have seen this issue after in operation maybe vibration from the air dome causes it to crack here. Hopefully going to sched 80 doesn't move the issue into the drain connection.

As a side note don't use teflon tape on plastic threads. It can expand and crack the plastic sides out. Use a small amount of PVC pipe approved teflon paste.

[Leecm3]

From the part circled in red , it looks like a part of the bottom drain itself broke off , and not just the threaded riser .

The piece on the center column pipe that is still attached to bottom drain cover and air diffuser is the coupler with male end, the piece still attached to bottom drain base is the female coupler with the broken threaded piece.



I was thinking of using a fernco fitting to attach the center column pvc pipe to the coupler still attached to the bottom drain. My main concern with trying to use a pipe extractor tool is the risk of breaking the coupler piece still attached to the bottom drain.

Based on comments above so far my options are:

1. Use pipe extractor to remove broken threaded piece from coupler still attached to bottom drain. Then add new threaded coupler to center column and reinstall bottom drain cover/air diffuser. This option has highest risk of failure do to possibility of damaging the bottom drain base while using pvc extractor tool.

2. Drain pond and glue internal spigot coupler to bottom drain coupler with broken piece still installed and glue center column pvc pipe to spigot adapter. Will need to install new threaded coupler to center column pvc pipe to allow removal / install of bottom drain cover/air diffuser. This option is less risk then option 1 but what is the impact to pond bacteria? Also requires removal of fish and also cost of filling 2500 gal pond.

3. Install a diy or store bought bottom drain cover and air diffuser that is standalone and not attached to bottom drain. Less risk than options 1 or 2 but requires a new air line to diy/store bought standalone bottom drain cover/ air diffuser. New air would be visible in and out of pond. If I were to drain pond I could install spigot coupler to run air line to standalone bottom drain cover / air diffuser so air pine pipe would not be visible.

4. Install fernco fitting over coupler still attached to bottom drain and the coupler still attached to center column pipe. Would need to add new threaded coupler to center column pvc pipe to allow removal / installation of bottom drain cover / Air diffuser. Would required to drain about 1/2 of pond water or hold my breath for a really long time to install fernco fitting, less cost than replacing all the pond water but still a cost. Not sure of any long term impact this may have on bottom drain base.

Kinda of leaning with options three or four with four being the easiest. Either way, not planning anything till around May when the water warms up. Regarding Rhino bottom drain, wish I could swap out bottom drains but that would be a job I don’t want to mess with now. Just need to look forward now on the best repair method.

[Leecm3]

You are very fortunate it didn't crack out at the base. I think there are threads on Koiphen where people successfully extracted the broken part.

Edit: Here's two

https://www.koiphen.com/forums/showt...-my-Koi-Toilet

https://www.koiphen.com/forums/showt...stem-broke-off

Thank you for the links, looks like this is a common issue with the koi toilet 1, wish I would of did more research when I was selecting hardware for the pond build.

[catfish whiskers]

If it is only the threads that broke , your in luck . The broken piece will come out easy , maybe even without an easy out or internal pipe extractor . I once made a quick tool to remove the broken threaded piece . If I remember correctly, the threaded nipple is 1 1/4” , so a piece of 1’’ PVC Pipe will fit inside . I simply screwed a pointed screw through one end of a piece of 1’’ PVC pipe , inserted it into the broken piece and unscrewed it out . As You turn the diy extractor , it will wedge itself against the ID and should unscrew easy . You have the broken piece to check the fit of the tool if You make it.
.

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.Another important point , the threads in the koi toilet riser are straight cut threads . You will need to get a male 1 1/4” PVC Conduit adapter as opposed to a standard 1 1/4’’ tapered pipe fitting . The riser pipe seals against the coupling shoulder with a rubber washer , hopefully You still have the old one .

[Leecm3]

If it is only the threads that broke , your in luck . The broken piece will come out easy , maybe even without an easy out or internal pipe extractor . I once made a quick tool to remove the broken threaded piece . If I remember correctly, the threaded nipple is 1 1/4” , so a piece of 1’’ PVC Pipe will fit inside . I simply screwed a pointed screw through one end of a piece of 1’’ PVC pipe , inserted it into the broken piece and unscrewed it out . As You turn the diy extractor , it will wedge itself against the ID and should unscrew easy . You have the broken piece to check the fit of the tool if You make it.
.

.
.Another important point , the threads in the koi toilet riser are straight cut threads . You will need to get a male 1 1/4” PVC Conduit adapter as opposed to a standard 1 1/4’’ tapered pipe fitting . The riser pipe seals against the coupling shoulder with a rubber washer , hopefully You still have the old one .

Great idea, I will try this on a test run, I will get male and female couplers screw them together and cut the male coupler and try your idea to see how it works. I got some time before water warms up before I get in the pond. Thank you.