Hi Colin, my tank is 120L Juwel, with 2 fantails and a bristlenose pleco . I do between 30-40% water charges every 4-5 days using a vacuum to suction the gravel. My water parameters have been very stable as a result with 0 ammonia, nitrite 0, nitrate 5-10 varys and Ph usually sits at 6.6. I have...