Alot of people have different apinions on when and how much for water changes, so i figured i would make it into a pole to make it easy for everyone to see!
I do 25% a week only because I tend to under feed a bit and also have plants. I find my tank stays healthy at this rate. If my bioload were to go up AT ALL I would be bumping it up to 50% a week.
I go normally with a 25% weekly, but according to situation I can go higher or lower. IE, if nitrates are getting higher, I do the 50%, which is normally every 4 weeks. At the same time, I clean my filters.
lol, my schedual calls for me to do a 20% every week (ive got relitively tough fish) but recently ive been buisy on vacation and other stuff, so it ends up being less often... ive started to get back into schedual with a 50% waterchange that i had last saturday... i should continue doing this once a week...
I took 25% a week to be on the safe side. I have a 29 with about 3 inches of substrate and I change about 10 gallons a week. so 33% if it was all water, so it might be a little over 35% counting substrate and everything. didn't want to say I did 50% though as I tend to do 50s only when my water is looking like it needs it