What Size Should My Overflow Be?

[jgranata13]

I'm getting ready to switch my freshwater tank to saltwater over then next few months, and I'm now finalizing plans and starting to work on all the logistics and such.

I'll be setting up a sump with a drilled gravity overflow, but I'm not sure what size pipes I'll need to keep up with my return pump. I'm not exactly sure on the pump yet, so if anyone could point me in the direction of a general resource that gives a range of figures for various flow rates, that would be great.

If not, let's say I have a 530gph pump with a static head height of about 38 inches. What should be the diameter of the overflow drain pipes te ensure that they can keep up? Thanks!

 

[jgranata13]

Also, is 10 X turnover per hour still the standard filtration guideline (not including circulation pumps, of course) like it is for freshwater or is it more?

 

[mr_X]

What size tank are we talking about? No, 10x turnover is not a standard.

 

[jgranata13]

My tank is 37gal. I was thinking since it's only an extra $20 I might get a pump rated for 725gph and then that way I'll have plenty of flow. Do you thing that'll be too much though?

 

[mr_X]

What size overflow do you have? That's how you determine what pump you need. for a 37, 300 gph or more is fine.

 

[jgranata13]

I don't have an overflow yet. I'll be getting my tank drilled, so it can be any size I want. That's why I'm starting with the turnover rate, so I can choose a pump with a high enough flow rate and then the drain based on that

 

[mr_X]

A 1" drain is plenty for a tank your size. You have to figure out the function of your sump and size the drain and return to make it most effective. For example, if you had a skimmer with a 300gph pump on it in the sump, you would need to send at least 300 gph to the sump in order for it to work at peak efficiency. I would not go under 1", and not over 1.5", so there are your two choices.