Originally Posted by aunt kymmie
As I type this my 75gl is draining, as I'm in the middle of doing an emergency water change. Did my routine water change yesterday, tonight I see my fish breathing incredibly rapidly, test the water parameters and have a .25 ppm nitrite reading, 0 ammonia and 10 ppm nitrate reading.
This is a cycled tank! What happened?? The only change was a brand new nozzle on the water change hose. I just checked my tap water- no nitrites in the tap. I'm really panicking as one species of dwarf cichlid in this tank can't be replaced easily as they are almost never available in the industry. I'm going to be gutted if I lose them.
Would there be something about a new nozzle that could cause this? Other than the huge water change I'm doing can anyone think of anything else I should be doing??
I do not think the nozzle was/is cause of nitrite spike.It might be possible that recent die off of cyno, may have caused a small ammonia spike followed by nitrite spike.
Have you by chance cleaned the filter recently? Could dead organics from recent bout with Cyno have collected in the filter and perhaps had effect on biological filter in low oxygen area as compared to HOB filters? Low oxygen in filter such as might happen during power outage,,could starve bacteria and dissolved Organics that may get drawn into the filter in this instance(s) , along with dissolved solids ,might present problem.
Same thing could happen if filter media was perhaps cleaned a little too well. Sometimes we clean too much media at one time,vacccum the substrate,,clean the glass,srub decor. Is easy to lose beneficial bacteria and as a result see brief ammonia and or nitrites spikes as a result.
Also helps sometimes to think backwards,(I do this frequently according to girlfriend).
Proper amount of dechlorinator used at water change, no dead fish ,snails,etc. No dying plant matter,No chemicals introduced to the tank, No Cats, dogs, peeing in the tank, no well meaning nose picker's ,or significant other's helping to feed the fish.
I believe something temporarily, may have compromised the biological filter and might use double dose of Prime for next few water changes while adding some bacteria borrowed from another tank or sponge filter from another tank to maybe enhance the biological filter in the Discus tank.
Hope some of this helps. Lee.