Plumbing help please


Active Member
I've decided to go with a single drain, and a single return for my tank. Now I need to figure out how big they need to be.
Would a 1" drain line be too big for an overflow only pushing about 200 gph?
Would 3/4" be better?
Second question . . . . regardless of the size drain, should the tubing remain consistent from bulkhead to sump? in other words, if it starts at 3/4", should it be 3/4" the whole way down, or should there be an expander or reducer along the way.
Third question . . . now the return, same as question two. Should the return line be the same diameter as the pump outlet from pump all the way to tank return? Or should there be an expander after the pump and then a reducer right before the return?
How big should the return line be in relation to the drain.


Question 1: A 1" would be fine. It may make a little more noise gurgling while it is draining.
Question 2: Yes keep it the same. You are more than likely going to have bends in it, or 90's, to get to the sump. I used a spa flex hose to route mine to the sump. Works great!
Question 3: I would try and keep it close to the same. Say within a 1/4" of the outlet diameter of the pump. If its 3/4" then stay around 3/4-1". If its 1/2" then stay around 1/2-3/4". I wouldn't reduce the size of the return line, but don't overkill it. The larger the return line the slower the volume will travel. Its only going to move as much water as the pump can provide. Like putting a 2" line isn't going to move anymore water than a 1" can, because the pump determines the gph it can move. Plus the larger the line, the more head weight that fights against the pump. There are good threads on this site that can explain all the theories behind this.