Raise water level

[Corwyn]

So I am wondering if anyone has a way of raising the water level a but on a 170.

I out on one of theose random flow out lets and the pipe stick out of the water I would like to raise it maybe half an inch but I'm sort of scared about a flood.

 

[Fishingandreefing]

You can put a small piece of acrylic restrict the water through the overflow. I did that but I removed it