Filter on 800-900 gallon pond, ammonia spike

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K626

Polypterus
MFK Member
Jan 21, 2008
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South FL
I'm currently trouble shooting an ammonia spike that almost took out our hybrid and rtc. We've got 3 different filters running. A small canister (up to 100 gallons) that we run simply to keep it cycled for the hospital pond. A uv fountain filter rated for up to I think 750 gallons. And a tote filter that we built running around 950gph (see poorly drawn diagram).

My thought is that there is some stagnant area in the lava rock in the tote filter that may have been knocked, releasing ammonia. Or the two pieces of drift wood are either decomposing or trapping ammonia underneath. I'm stumped. This pond has been up and running well for a year. Stock is currently 1 24 inch rtc, 1 30+ inch hybrid, and a very naughty 8-10 inch jaguar cichlid. That's it. Pictures to show set up.

If anyone can maybe think of something else, I'm all ears.

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Both submerged filters are just trapping waste, not removing it. Bio filtration seems insufficient for the bio load. And u need a much more efficient external mechanical filter in my opinion.
 
How big is the pond? 900 gallons? I'm in the opinion that you also need more filtration. From what you're explaining you're pumping 1800 gallons/hour through your filters, but that pond has to be pretty big? My 166 gallon Fahaka tank has a pump on it rated for up to 2400 gallons/hour (minus the head height, it's probably about 2100 gph). So the water is being pushed through all my bio media almost 15 times an hour. That being said, the spike could very well have been caused by some detritus being stirred up, but you should have enough turnover and bio filtration on a system that size to handle it "sans problem".
 
The whole bottom half of the tote filter is lava rock, so approximately 5 gallons worth of that rock. I'm a fan of mass biomedia. With all the research we did, I had hoped to avoid this but that tote filter was a back up to the original plan that failed. The pump is the jecod 4000l/h pump. So I'm thinking if I up that to the 15000 and add an air stone into the bio media it may help? I'm running both an fx5 and an fx6 on a 125gal tank, and looking at that, I can see where the water flow could be the issue. Between the two filters though I had hoped it would be enough. Pond is 8 foot by 6 foot by about 26-30 inches deep.
 
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Both submerged filters are just trapping waste, not removing it. Bio filtration seems insufficient for the bio load. And u need a much more efficient external mechanical filter in my opinion.
Any filter simply traps waste. It all stays in the water, unless you've got a wet/ dry system. Even in canister filters etc. Only way to actually remove waste is cleaning the mechanical filtration out or siphoning.
 
My biological system isn't sufficient then due to the flow being low. ? So, how does this sound:
Upgrade to 15000
Larger tote, more lava rock
Instead of the top down, run a different style, same concept, but with the filter mostly out of water where it's pretty much gravity fed through mechanical then through bio and out the side. It's not easy running filtration gph as high on a pond as we would in a tank. In theory, more bio media would do the trick with sufficient water movement / aeration in the bio chamber even without a 10x turnover rate?
 
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I would upgrade the pump but then mount a box filter in the corner above the pond. The box can still contain chsngeable floss for mechanical, and lava rock or alpha grog for biological and can have the return pipe at the base to keep it lighter, essentially running dry to keep oxygen turnover high. Will also add flow to the pond and good airation as can feed the filter via drilled 40mm pipe spray bar if you wish.
Ammonia spike could be either of the fish regurgitating food.
I have a 1500 usg pond which has the above setup and the box filter is a 36”x18”x24” box rated for 10000g koi pond.
 
I would upgrade the pump but then mount a box filter in the corner above the pond. The box can still contain chsngeable floss for mechanical, and lava rock or alpha grog for biological and can have the return pipe at the base to keep it lighter, essentially running dry to keep oxygen turnover high. Will also add flow to the pond and good airation as can feed the filter via drilled 40mm pipe spray bar if you wish.
Ammonia spike could be either of the fish regurgitating food.
I have a 1500 usg pond which has the above setup and the box filter is a 36”x18”x24” box rated for 10000g koi pond.
I haven't seen any sign of regurgitating food. They eat whole tilapia filets or half filets. That was my thought for the tote, but elevated in the pond with milk crates or similar. If I can limit any possibility of a flood, that's the avenue I'm taking lol. We originally planned that type of filtration but the buckets we bought for tandem wouldn't keep a seal and my husband is impatient. ??‍♀️ I'm going to most likely be planning and building this while he's at work, so it'll get done one piece at a time for now. I'll just have to keep testing daily and monitor the situation. I added an air stone in the bio media, so we'll see if that helps at all until I get this built.
 
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