Lesson learned

[smalltownfan]

In the community tank we lost 6 fish this week.    After the first loss, 1 fish (Blue Ram), I checked levels, only did ammonia and nitrite (because I ran out of nitrate solution) both normal. Two days later lost 2 more (Blue Ram & Neon) checked again, both OK. This morning 2 more (Otto & Neon!) Both levels OK.  ?? WTF!
While at LFS today, to picK up some odds and ends I picked up Nitrate test refills, came home, found I lost a female guppy.
Did the Nitrate test....don't want to tell you the result  but I immediately did a W/C, had to be at least 75%. I did a 25% 10 days ago. I don't know happened!!!  But......From now on..all three tests if there is a problem.

I did add a CO2 ladder and a CO2 generator three weeks ago. Plants have shown amazing growth. Could this be a cause? This tank has been up and running for almost a year with no problems till now.

[dan2x38]

What have you been fertilzing with?

[robt18]

Plant growth typically brings your pH and nitrates down. Were your results way too high or low?

Have you tested your pH? I'd say that would be the more likely culprit... unless your nitrates were high enough to give the fish nitrate poisoning, but when that happens you usually notice some weird behaviour.

Blue rams are extremely sensitive too... those ones may not have been entirely your fault!