yaeh water change is a good thing, but how come i'm still getting high nitrate when i do 25% wc every week with RO water. I also run 2 fx5 and 1 2028 for a 220g tank.
High nitrates are something that are part of keeping big fish i do 2 x 25% water changes per week and still my nitrates are 100ppm it cant be that bad for the fish as my rays bred in that nitrate
their are a few diffrent options for high nitrates plants being one of them but thats not an option for me as the rays will rip them up in a few mins
you can use a nitrate reactor i had an expencive shuran one running on my tank and the are not that great you have 2 ways of setting up the nitrate reactor 1 is with sulpha beads this doesnt work that well and it makes the PH drop
the other way to set it up is fill the reactor with siporex and feed it with alchol this method is ment to be better but i cant be bother to feed it every day/week
the way i look at it is if you have high nitrates then your filter are working fine as nitrates are the last part of the cycle
i have never use RO water as i find it pointless taking all the stuff out of the water just to add new stuff
if you have amonia or nitrie then you have filter problems