PROBS WITH NO3 again

heyy all, 75g community juwel trigon 350 tank is doing it again. My Tank is stocked with 5 geo surnimensis 4 boesemani 2 paradise fish 2 juvi sevs a firemouth and a 8" common pleco.

I recently posted MOUTH ROT WHAT NEXT a thread saying how my no3 was spiking at 75. I cleaned and changed water accordingly until i found that my canister was hiding a mass of mush under the bottom cage. I removed and changed even more water to compensate {about 50%} and the no3 dropped down to 25. Iv stepped up water changes since this little prob started and again. Tonight after my bi weekly change the no3 is back up to 75. I change 15% twice a week and this has always worked.

I recently removed 4 sevs to an aquatics shop as to lessen the bio load. Even so I think larger water changes are needed. This is confusing me a little as ive never had any probs before.

The boesemani that had the rot has healed well but is still showing a small whit tuft on his mouth tip. The sunsun 1400lph epf has a 9w uv on it that i have turned on for the past 2 weeks.

I know that im going to have to up the water changes but can any of u think of anything else it could be?????

My nitrites are 0 and ammonia also 0. I will do a 50% this morning and test again!

I am using test strips, the n03 indicator starts completley white and gets pinker the longer i watch the strip. This i do not like as obviously this can cause panic and dilouted results. the instructions read, take reading 60 seconds after dipping. I do not like this as if not timed correctly you get a darker or ligghter result.

I just did a nh3 nh4 api test that read 0......

Ok my filtration was choked with gwaano again, no idea how so much had got stirred up when removing the severums. This must have dropped filtration and built up n03. Cleaned out filters this a.m. and just did a WC 25%. Readings are good as n03 is under 25.

Going to have to keep on top of this tank, thanks for yr help all

Ok my filtration was choked with gwaano again, no idea how so much had got stirred up when removing the severums. This must have dropped filtration and built up n03. Cleaned out filters this a.m. and just did a WC 25%. Readings are good as n03 is under 25.

Going to have to keep on top of this tank, thanks for yr help all