And yes the 4th whole is the return just haven't gotten the chance to put it in yet. And the pipes are short for the first few months to cut down on water. And to make sure everything is working good. I will take your ideal on making one a bit taller. And I have a overflow Bulkhead with a 1 inch hole for when I do My drip system all the extra water will overflow into my drain. On a power outage the extra water will over into my drain . That's why I'm taking my time doing everything. I'm thinking ahead lol. Thanx for the good advice guys. I will use some.