what size overflow box should I get?

[WXB]

For my 40gal breeder. With a 700 gph return pump whay would be better the eshopps 300 gph or the 800 gph overflow box? I am trying to figure out what size to get. I was told to get a 600gph overflow for a 700 gph return pump. I can not find a single U tube with 600 gph overflow box. Would the 800 overflow be too much for a 700 return pump?

 

[n00311]

did you think about looking at glass-holes.com

 

[ggrillo]

Overflow needs to be more than the return pump otherwise your sump will drain and you DT spillover

 

[Donkeykong]

you always want the overflow to be bigger than the return pump. Also remember the closer to the max rating you are on the overflow the louder they tend to be. So if you plan on running 700gph return pump I would go with the 800gph overflow. 700gph is high turnover rate for a 40 gallon breeder. I have a 300 gph on my 40g and am very happy with the turnover. You could run a 300gph over flow with the bigger pump and just have the pump split. One side can go up as a return and the can be used to run a reactor.

 

[WXB]

I also have a 320 GPH pump as well. If I split it off and ran one to one end of the tank and the other to the other end? I understand 700 GPH is high for a 40 gal. It's what I got. I just want to make sure I get this right. I don't want to spend money and have to re-do it.

 

[WXB]

If I use my 320 GPH return pump then get a Eshopps 300 GPH would that be ok?

 

[Donkeykong]

Also remember that a pump looses flow as it has to deal with head pressure, so say the pump has to push the water up 3 feet it will no longer be pushing 700 but probably around 500 depending on type of pump. If you want to use a bigger pump than the over flow can handle you can split the return and have some of it just go right back into the sump or like I said earlier if you are going to run any media reactors you can have it go there. If you split the flow but have both go to the main tank your still going to have a problem if the pump is to big for the overflow. Also you can add a ball valve to the return line, then you can actually turn down the flow from the pump so it matches the drain. I have a glass holes 300gph setup with a tunze return pump rated for 640ish. But once you factor in the head loss and loss from plumbing it is actually nicely matched, I do have the ability to dial it back a little if the drain slows from natural build up.

 

[WXB]

I like the glass holes.com idea but I am soooo not drilling into my tank. that is soo not going to happen. Besides the tank is set up for 4 years now. It is a bit too late to do the drilling. I like the U tube ideas. I am just trying to figure out what size overflow box for the 40 gal and what GPH return pump is best. I have some equipment that I would like to use instead of buying more. If i have to buy more so be it.

 

[gldnegle76]

For a 40 gallon, a 300gph overflow should be fine. Use a ball valve or split return or both like Donkeykong suggested. I have a 46 gallon bow and use the Lifereef Nano Overflow that handles 400gph. My return pump minus head loss probably pushes about 450gph. I have it throttled back with a ball valve.