Is it true bio balls in a canister can cause nitrate problems?
 

I recently bought a marineland canister around Christmas time and since then I have had a nitrate problem Which I never had before....is it true that bio balls will cause nitrate problems?

I have a canister filter on my 75 gallons and zero nitrates, but I have lots of macroalgae that export the nitrates.

I use the filter mainly with floss and carbon filtration. I clean it every 4 to 6 week.

I would not put bio balls in it because if you have good liverock it is better as a filtration than bioballs. A filter with bioballs is just to process ammonia into nitrates with nitrifying bacterias. Liverock does a much better job at it and if you have very porous liverock, it will even help denitrification with anaerobic zone deep in the rock. I have Totoka liverock and that help a lot to export my nitrates as well. I feed 3 times per day heavily for my hippo tang and niger trigger and I still have zero nitrates despite having a canister filter. So it's only a part of the system but a lot of other things count more.