Yeah, nitrogen is number one ingredient in plant fertlilzer. And also in poo.....
Id go with the canister, I really would. I get sick of buying HOB
filters only to have them last for 6 months and then stop working completely, especially cheap ones. Actually I had to get out of bed last night at 2am because the spashing sound from my 40G was getting so loud from the water level being low I couldn't sleep. Dream about filling the bucket up and stopping the annoying sound then actually wake up and do it....strange I had to pee really bad too! lmao