How chose a pump for my 70g tank and 25g sump?

[theguyinasia]

Hi everyone,
I am currently looking at buying a pump for my 70g tank and would like to know if a pump that is too powerful will have disadvantages. I am looking at a 900g/h Eheim or a 630g/h. any help would be great:smile:.

 

[Xingu]

A pump that exceeds the capacity of your overflow can empty the sump and overflow the tank. You should try to get one that is close to the rate of your overflow.

 

[theguyinasia]

I have decided to go with the 630g/h return pump and i am confident that this will suffice. that being said, my overflow will be around 600g/h. is this something i should be worried about or can i match my pump to meet the rate of the overflow?
I have the link below for the overflow from Reef life that i am purchasing now. i think this really can do the job well.... well i hope haha

prefilter box, siphon box, overflow box, siphon overflow, Eurobrace, Euro-brace, Euro-tank

 

[Reefing Madness]

With loss of head pressure your pump wont' be at 630gph, it will be under. Look up the specs of your return pump, it will give you head loss per foot. But in case you change pumps, you branch off the main return pump with a line that goes back to the sump, with a ball valve on it, this can be used to fine tune your return if need be.
Melevsreef.com | Acrylic Sumps & Refugiums

 

[theguyinasia]

Madness,
i didnt calculte that in at the time, but that makes more than enough sense. im quite comfortable with with the setup then.
thanks