How to determine GPH sump pump

[ctylermast]

So I’m picking up this system this weekend, already has overflow installed, don’t know what kind or model etc etc. so idk what the gph rating is. My question is , it doesn’t come with a sump pump, I’m also changing out that sump with my 40g sump that I made. Anyways, how do I calculate or determine how many gph I should get, when I don’t know details on overflow.

 

[mmorrison55]

5-10x turnover is usually plenty. Some prefer 3x and some will tell you that you need more.

So for a 40 gallon look for a pump rated around 400 gph give or take.

Dc pumps are preferred as you can easily adjust their speed up and down. So if you wanted to get around a 750 -1000 gph pump,you could then turn it down to operate @ 30-50% power so that it’s more efficient.

 

[bushdoc]

10x turnover is on a higher end, I would aim at 4-5x, but you have to take into consideration head pressure, so how high your pump is going to deliver flow, how many bends of a pipe. Many pumps manufacturers provide curves for that. DC pump is ideal, but more expensive than AC pump, so many reefers uses AC too.

 

[mfinn]

So I’m picking up this system this weekend, already has overflow installed, don’t know what kind or model etc etc. so idk what the gph rating is. My question is , it doesn’t come with a sump pump, I’m also changing out that sump with my 40g sump that I made. Anyways, how do I calculate or determine how many gph I should get, when I don’t know details on overflow.

You need to determine the diameter of the pvc pipe/bulkheads in the overflow box. How many and what size.