Hi, i am currently setting up my tank for discus. we have had it running for about 4or 5 weeks with 14 cardinal tetras, 6 rummy nose and 7 black widow tetras. it is a back drop filter system using noodles, filter wool and eheim substrate. a thin layer of gravel and some anubius. cabomba, elodea and java fern who all seem to be doing well so far... anyway question is how do we keep our ph constant.. we have peat in the back also which brings our ph down to about 6.8 after about 2 days. then as soon as we do water change (which at moment is once a week) the ph goes up to a bit over 7 but i wouldnt say 7.2. I am worried that if we put discus in they may not like 7 and i know they wouldnt like the ph changing everytime the water changes! any ideas or tips would be appreciated.