return above or under

[AdamsB]

I would go below the water surface. Otherwise It'll cause a lot of splashing as Aquattro said. Also If your power goes out and water drains to the sump, once the pump turns back on you'll get quite a bit more splashing till things even out again. I'm thankful for my glass lid. I had the loc line 4 inches below the water surface pointing up. Power went out, came back on 5 mins later and pounded my glass lid. That would have been a wet carpet and dry sump. Although I anticipated it, it's nice to see it in action an know if I'm not home things will be fine.

So consider what happens during water changes, power cuts etc. and remember, salt water will permanently stain drywall.