Backyard Aquaponics
A place to discuss aquaponics

Did water test Sunday after noticing fish looked a bit "off". Test confirmed high ammonia and Nitrites. With held food for a few days and retested. Ammonia back to .25, but Nitrites still over 2. Any ideas on why this would happen? Ph has been stable around 6.9, temps are in low 70's, sometimes upper 60's. I'm clueless and don't understand what happened. I'm doing a partial top off with well water to bring sump level up and will test again tomorrow to see if I can resume feeding fish. They seem normal again and are hungry. A bit concerned about my crops, especially Toms, which are doing great and I know need more nutrients.

Dead fish maliciously hiding some where?

It could be Stuart, I haven't seen the bottom of my FT in over a year. The Fe and humic acid make for poor visibility. Wouldn't I also have high ammonia? I had that a few months ago(4-5 now) and finally discovered it to be built up muck surrounding the pump in the sump. But, my ammonia is zero to .25?? Actually just tested again, and finally down in the blue area. Time to start feeding the fish again. Another possibility: With the cooler weather, I've been shutting off the pump when the temps in GH dip into the 60's. I was still feeding fish 3 -4 times per day, with the last time being late afternoon. Maybe shutting off the pump and allowing no circulation in the FT was causing a problem? I didn't check the water in the sump or DWC. I'll check all tomorrow before feeding fish. Very cold here tonight, with frost predicted. I have to go cover a bunch of tropicals up so they don't get whacked by the cold.

The shutting off the pump is most likely causing the problem. With no pump you have no biological filtration happening.

Yeah I wouldn't be doing that and feeding heavily.

My ammonia levels climb when the pump is off. I haven't done a timed study but I do know that I don't want to leave the pump off over night if I've given a full complement of feed that day.

Makes perfect sense to me. Now the problem, with Winter temps sometimes in the 20-30'sF, and my poly GH with electric heater struggling to stay in the 50's, if I run the pump my water temp will drop like a rock. I guess I have 2 options, get a bigger heater, or eat my tilapia and raise catfish or koi. I'm not too fond of catfish, and like eating fish, not just looking at them...so I guess it's a bigger heater. Need to look into rocket heater or something non electric. Anyone have suggestions for an easy, cheap heater?

Are you reducing your feed rates to coincide with declining temps?

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and I wonder if there is a graph anywhere of Bacteria Effectiveness Vs Temp..

What about setting up a special tank/filter, filled with say - shade cloth, and a small pump to circulate through there at night..
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http://www.wetwebmedia.com/ca/volume_7/volume_7_1/dsb.html

http://www.americanaquariumproducts.com/nitrogen_cycle.html
http://scholar.google.com.au/scholar?q=deep+media+anaerobic+cycle&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ei=neaIVNuoCM6B8gXrn4LwDA&ved=0CBwQgQMwAA

I have reduced feed, zero for the last 4 days.lol I will try and keep feeding earlier in day, so that if i must shut off pump, then hopefully much of waste is out of FT before I shut it off for the night. Tried letting temps build higher during day, but that didn't work. It was over 90 at around 3:30, and by 5 was already in the 60's. I guess poly is not a very good insulator. I'm going to look for another heater to try and keep Gh around 70 and then I can leave pump on.

Salt to 1ppt if you haven't already.

If you want to stop pumping through your grow-beds for periods of time - what about adding a biological filter to your system that can be left on? Nothing wrong with relegating biological filtration to a side-stream process. Could be as simple as an aquarium canister filter with some bio-media in it, or a bead filter. A MBBR would do the trick, but all that air might cause cooling?

Not sure of the BSA of my 24 sq ft DWC bed, but I could shut off MB and towers and just run that. I would still have circulation, shouldn't cool as much and might help with my Nitrification?? I'm checking all this AM. Should all be a zero. 52 in GH this AM.