I have an established 75 gallon, heavily planted. Had hundreds of cherry shrimp breeding like cockroaches, handful of amanos. Assassin snails, nerite snails and a pest snail problem kept bearable by the assassins.
fish: 3 otos, 6 threadfins, 3 dwarf neon rainboes, 8 rasboras and 8 mixed tetras.
high tech system with injected co2, 204w total t5ho, 12 hour light cycle
2 days ago, my kid dumped an obsene amount of food in the tank. Scooped out what I could, but I had to go to work.
yesterday, nitrites still low but did 30-40% water change to get the rest of the food out (a lot had broken down, the rest had been eaten by shrimp).
Went to work. This morning, all amanos and nerites dead. Pest snails dead. Assassins chilling at the top the tank (presumably alive) over half my cherries dead, rest at the top including shrimplets. All fish alive but gasping.
did tests. Nitrates 5pp, ammonia spikes at 2ppm and nitrite at 3 ppm (estimated based off change-- cards went missing).
Co2 is fine-- the thing had just turned on and my kh is 5, ph 7.2.
wth???? Any ideas folks? I dosed 4x amount with prime (instructions say can do 5x but I played it safe), so should be neutralized. I haven't dug all the casualties out yet cause it just happened. It's gonna take me all day...