The Puffer Forum

No a skimmer doesn't work below an Sg of 1.018.

is a sump neccesary??

No but some ppl use them in FW and BW thou. It add water volume and some even add plants etc to them create a natural food source. I have only used a sump for SW. Someone else would have to tell you more about the benefits of a sump FW/BW. I personally think you'd be fine with a good HOB. Just make sure it's made for double the size of the tank. Say if you got a 75g I'd get a HOB for a 150g or even better a under the tank canister filter like a fluval fx series

so what kind of hob filter would you recomend

I'd say aquaclear but the fluval fx series would be better. You can buy parts to extend the intake vertacally or horizontally. It will have much better filtration. And it has a jet spout so you can aim the flow of the returning water. Say if you deciided to go marine in the future I'd go with a HOB for now then a Sump. If I were to stay BW I'd get a fluval.

very high level brackish water starts to show SOME skim at SG 1.015, but does not really seem to "hit" or engage fully until SG 1.0175, plus or minus, depending on the skimming tech and the layout. 1.020 or higher should _always_ have a skimmer.