help with sump

Way too small of an overflow, just IMO. With a sump/fuge you want about a 10X flow rate, higher if its just a sump

 

well will it work ? or what is the big deal of it being small the sump is only 20g

 

For a 90g, I would have two 600GPH overflows powered with two Mag 7s. I am in the process of saving money for my second Mag-7. When I get that in order, I will have my two CPR 600GPH overflows, one return powered with a Rio 2100+ and the other a Mag-7. At five feet, that will give me about 1050GPH turnover from DT to sump. That is 12x turnover. I was aiming for 10x.

300GPH is not enough IMO. You would use this overflow in something like a 30g.

 

My sump/fuge is a 20g long as well.

 

E-Sump Overflow Boxes for 75 Gal. - eBay (item 320182933361 end time Nov-08-08 19:20:29 PST) that is the overflow i have it says up to 75g should i wait then i get a bigger overflow box then or will this one work

 

The size of the sump doesnt matter so much with the flow rates, its the size of your DT that does. It might work, but it would be very ineffective and you would lose the advantage of even having a sump in the first place. It would be like putting a skimmer on your tank that is meant for a 20 gallon tank. Sure it would work, but would it even be worth it?
For a 90 or 100, you should be looking into overflows around 1000GPH+, with the return pump to power it. 300GPH would be good for a 20-30 gallon tank. I'm building a fuge for my 40 and its going to need a 600GPH overflow, if that gives you a better idea.

 

what is dt and maybee i was reading it wrong there is a link below what overflow box i have

 

DT= Display tank

 

idk what the gph is ....... that was the moldel number i read lol

 

Here is an idea of what I would get. Now......this is not a CPR brand name OF box. I do not know if it is any good. I would do some research before buying it. You can power the siphon assist with something like a Maxijet 600. I would get two of these (or something like this). Remember to research this purchase before getting it. I do not trust off brands in this hobby.

Continuous Siphon Overflow Box 600gph FREE S/H & GIFT! - eBay (item 330273906082 end time Nov-23-08 10:59:19 PST)