I bought two AquaTop submersible heaters on ebay for a few smaller tanks... was REALLY impressed with the quality and price... very sturdy with protection at the bulb end and a button to recalibrate if they get off the mark. Went to the web site and noticed they have canister filters that are much cheapter than the FX5 I bought a few months ago. Has anyone used these canisters? If so, what do you think of them? Thanks in advance for any response!