art_b

I keep my nitrates to about 5 ppm or so. I do 50% water change every week, and add KN03 to maintain at least 5 ppm nitrate. I had only a few occasions where I would dose KN03 during the week to top up my nitrate to the desired level.

I was thinking of replacing or supplementing the Eheim Substrat Pro in my canister filter with Seachem Matrix. My main worry with Matrix is that it might remove the remaining nitrates in my tank. I do not want to dose KN03 just to be removed by Matrix.

How aggressive is Matrix in removing low level nitrates in a tank ? Is Matrix suitable for my planted tank as the sole biological filter media ?

Seachem

Your plants will more than likely utilize the KNO3 rather quickly, so I do not feel that you should worry about Matrix removing the nitrate. Matrix will allow you to keep your nitrate level in check and under control. Matrix is definitely suitable to use as the sole biological filter media in your planted tank; we do so here in our planted tanks at Seachem.

Bunbuku

On a related note, does Matrix ever need to be replaced? In other words do the pores in Matrix eventually get clogged up as to render it ineffective?

Seachem

Matrix does not necessarily need to be replaced as long as you have taken it out every once in a while and rinsed it in order to remove any debris/build-up/sludge/etc. This will prevent the pores from becoming clogged. However, if you do choose to replace Matrix (which is perfectly acceptable), you should only replace 1/4 to 1/3 at a time, so as to not remove your entire biological filter. Just swap out some new Matrix for the old Matrix; this will allow the established bacteria to trickle onto and colonize the new Matrix (you can also add Stability when you add new Matrix).