I find that, in practice, canister filters when hooked up and full of media usually produce about 60%-70% of the output stated by the manufacturer. So it's just a matter of taking that into account when calculating the total output of your filters to achieve 4 to 6 times turnover of tank volume per hour.Fishowner24 said:What do you mean “halve the manufacturer's stated flow rate for the filters.”? And would I get 2 of those filters since I want 2 filters or should I half the 220 to 330gph and get to with half of the gph?
However, I don't use HOB's and don't know if the same applies to them. Since you're considering them it's probably best for someone else to comment on the model you're looking at.
Might be best to start a separate thread on filter selection since it is off topic.