Opinions appreciated: check valve vs anti-siphon holes in overflow returns

[Myka]

Originally Posted by gregzz4

I'm going to try this. On the right of the overflow box is a 'Y'
It and the nozzle pointing forward are twisted to their max and cannot point down any farther. This nozzle will be the siphon break
The eggcrate cover won't fit if they change position so it'll alert me if I bump it during maintenance or WHY
Now I can still have the surface flow I was looking for
Hopefully this will eliminate dead spots on the surface corners

I didn't mind your first idea, but this looks good to me too. IME, the loc-lines are pretty stiff so you really have to give them a good knocking to move them. You can always do test runs with the lines lower to see if there is room in the sump. If your sump can handle the flow with the loc-lines at their lowest point then you're covered anyway.