I have 75 gallon high tech setup. I converted from cichlids back in November 2019. Filtration is Eheim canister with two baskets of bio-balls in one and ceramic tubes in the other. Mechanical filtration with foam, floss, and another finer foam in the second basket. No chemical filtration. Tank inhabitants include 12 rummynose, 1 cardinals, 6 Juli Corydoras, 3 bleeding hearts, 4 marble hatchetfish, 6 ottos, 5 zebra snails, 6 amano shrimp, and 3 Siamese algae eaters. Substrate is caribsea black for planted tank.
pH is 6.6-7, depending on the time of day. GH is 4, KH is 3, Nitrates 5-10, zero Nitrites. Light’s are on 6 hrs/day, CO2 is same. Some hair algae, but not bad. No other algae problems. I have been doing weekly water changes of ~25-30% recently. Water input is RO water conditioned with Equilibrium, Alkaline Buffer, and Acid Buffer to match tank conditions.
Daily fertilizing regimen of Seachem Flourish, iron, Nitrogen, Phosphorus, Potassium, per Seachem’s daily dosing recommendations (I.e. I’m not doing each one each day..they are staggered).
About a month ago, I fought some sickness with antibiotics and, afterwards, noticed the ammonia levels had spiked a bit. I used Prime to neutralize, did a 30% water change, and kept monitoring. Tank inhabitants seemed fine. Over the past month, I have continued the weekly water changes, tank inhabitants all continue to be fine, and all water parameters besides ammonia levels have been normal. Ammonia continues to be high and I can’t figure it out!
There is no sludge buildup on the bottom of the tank or anything, no abundance of decaying plants, no dead fish, no over-feeding. Ammonia is at 2.0 or so, which would normally be alarmingly high, yet the fish continue to seem fine. I got a new test kit and it reads the RO water as normal and my tank water as high.
Any suggestions? I’m hesitant to add more cardinals (they died out with the sickness) before I get this thing figured out. Thanks in advance!