I cleaned the filter not that long ago after that picture, here is there current state, i just rinse them in tank water, same as always.Those Bio-balls look really clean. what is your washing method? They should have a bit of "slime" on them. The bio media in my 55's filter is kinda green/brown. When I clean my filter media, I do a water change and rinse the media in the old tank water.
This tank has been with me for about year, i got all these fish at this size, all full grown, never have had i had a problem with water perimeters, i recently did cut down on stock too, i had a pair of midas, both around the 30cm mark, my stock list is fine i think...Maybe your stock is just simply too much for your filters to handle regardless of how many water changes you do. You may have to rehome some fish.
***Jack Dempsey Cichlid Lover***
I'll cut the water change and see what happens, as i said before the fish haven't grown, only things that has got bigger since i got the tank is the 5cm clown loaches that are now 8-10cm, that's it, maybe my problem is that my water change schedule is to much, but if i don't my nitrates get to high, maybe i may have to rehome a few oscars, but it makes no sense because i have had this stock for a year or so...Perhaps BB colony is crashing for whatever reason. Are those bio balls in that one canister all you have for bio media? Perhaps it is no longer adequate with the growing stock in your tank. Is it possible to rehome some of your fish temporarily and see if less fish in the tank resolves the issue.
I think going to 50% every 2-3 days is something you should definitely try......but keep checking those parameters daily.
Well last thing i can remember before this started was re homing my midas pair, around 30cm, so i did loose a decent amount of bio load, but i have 4 oscars and 2 plecos, so yeaa lol.So, Obvious question... Were there any changes of load or media type before this issue? It sounds like you are doing everything right. Did something change? Did you add fish, change your pump, add gravel... ? Something triggered the issue. Did you change anything at all (even small things) in the weeks before this issue started?
Katie's tank does a weird balance shift two days after she adds ghost shrimp to feed her Bichir, but it always comes back with in a few days even if her beast has not eaten all of the shrimp yet..