why shouldnt i use a canister filter?

[Pufferpunk]

Ok, here's the deal. All man-made filters cause the end result of bioligical filtration to become nitrate. In FW & even BW, large WC are necessary to remove nitrate. Go ahead & continue to filter SW as you do FW/BW with your canisters & HOB filters but be prepared tp spend a ton of $$$ on salt, for those WC to remove the nitrate. Or... use live rock & a protein skimmer & do waaaaay le$$ WC. Your choice.

I'd also like to comment on using rubble in your HOB or canister. I have AC HOBs on my 15g & 40g SW tanks. Both only contain rubbble. It does work quite well for adding flow to the tanks & I'm sure it makes a geat fuge for pods to multiply in. Except that about every 6-8 weeks, they get completely clogged with detritus, the flow is almost nil & I have to rinse it all out with SW from the tank--washing out all the pods--so it really isn't the best idea either.

[splitadams]

im not even keeping a marine tank at the moment i was just asking so i know for future reference

[Pufferpunk]

It's always good to do research ahead of time.

[xmikebrock]

oh yeah it is