I have a fluval g6 that I've used on a reef tank for some three or four years now. I don't use it for bio, but use the baskets for things like carbon and matrix etc. I have never had it leech things back. It's not really inexpensive, but it tells me when I last changed everything, and I just follow the alerts I set in it to tell me when to change things (you may have gathered, but I have the memory span of a crack addled ferret ) I do run to large dumps also, one for heaters and skimmer, one the scrubber dumps into. The downsides to just a canister, imo
, less overall water volume (opposed to having a sump) less aeration also ( cascading effect, as well as skimmer ) the higher the water volume, the less a slight chemical change effects.
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