I skipped to last page, my apologies. While you're battling the spikes, have you considered an ammonia/nitrite detoxifier? Doesn't eliminate them, but takes the toxicity out to protect the fish. (After washing the sponge, most likely resulting in a unwanted cycle, so nitrites are probably up too)
This way, the ammonia remains in the water for the BB to build, while not being dangerous to fish.
It's what I used for my 90g fish in cycle. Haven't lost a fish yet, all healthy.
May I ask, why must your filter sponge/particle pad be so clean? I find the best quality water comes from the dirtiest filter lol Rinse it every few months. I have the same Fluval and haven't change my sponge in 8 months. I just stack my biobead and other media replacements.
The more water changes you do while the Fluval is trying to cycle again, the longer it will take for it to be able to handle the bioload and keep ammonia down.
This way, the ammonia remains in the water for the BB to build, while not being dangerous to fish.
It's what I used for my 90g fish in cycle. Haven't lost a fish yet, all healthy.
May I ask, why must your filter sponge/particle pad be so clean? I find the best quality water comes from the dirtiest filter lol Rinse it every few months. I have the same Fluval and haven't change my sponge in 8 months. I just stack my biobead and other media replacements.
The more water changes you do while the Fluval is trying to cycle again, the longer it will take for it to be able to handle the bioload and keep ammonia down.