new to hobby filter conversion?

[Trigger Happy]

Pescodor very good point, I did see one of those ehime surface skimmer attachments. Hmm I realize I never had that problem because of the closed lids on the freshy. But I believe I'm not suppose to cover the tank due to overheating. So I better find one of those.
Justinl if I put live rock rubble in the canister do I fill it? And the rubble can you buy it or do you make I with a hammer? I am not putting carbon or phosban in the canister. I was shown how to make an old reverse osmosis into a reactor. Thank again for the advice everyone.