Hi, I am returning to a reef tank after an absence of about 10 years. I have treat myself to the Fluval M40, which looks very smart and I am hoping a good little starter for coming back to the hobby. I will be collecting the tank and cabinet this weekend and am itching to go. However, I was wondering if anyone has set up a under tank sump, using the tap on the back as the outlet for the tank to the sump. My intention would be to run a better skimmer in the sump along with a backup heater. Any ideas warmly welcomed.
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