How fast does water drain?

[calgaryreefer]

Hi everyone, just in the process of matching pumps to new tank, I have a 125 galllon tank with a external overflow box built, it has an 1" hole, I was just wondering if anyone knew how fast that drains, it will most likely have a few inchs of water built up in the overflow box, the overflow box is about 4"(depth)x8"(long)x10"(high).

Thanks everyone.

[Myka]

There is only one hole in the overflow box? Usually there are two. Most medium-sized tanks are drilled 1" for return, and 1 1/2" for drain. That's how my 90 is drilled. I wouldn't want a 1" drain on 125 gallon tank...that's too small. 1" will only handle 600 gph, and it won't take much to clog up. You should have room in the overflow to drill a second hole no?

[xtreme]

This chart may help, but as Myka said I wouldn't try to push more than 600GPH through a 1" line so don't take those numbers as gospel.

http://flexpvc.com/WaterFlowBasedOnPipeSize.shtml

[calgaryreefer]

sorry guys, yeah there is a second hole, but I don't plan on using that hole, I am just gonna plug it up with a bulkhead cover till I need it. But yeah you guys might be right about the 1.5" hole for drain, can't remember exactly, but i think there is only a 1" clearance in the pipe right?

[Myka]

If you have two drains, why not use them both and do a Herbie style silent drain? That's what I have going on my 90. The 1 1/2" bulkhead is my main drain with the 1" as my backup drain. :)

[untamed]

If you have two drains, why not use them both and do a Herbie style silent drain? That's what I have going on my 90. The 1 1/2" bulkhead is my main drain with the 1" as my backup drain. :)

+1 on this suggestion!

Also...there aren't easy answers as to how much water will drain through a particular pipe size. How much goes through depends a LOT on how much water is above the hole, and how much vertical drop there is to the sump below.

[calgaryreefer]

hehe I am just too lazy to do all that plumbing work, and the tank is in a place where noise isn't a factor.

so yeah is there a chart that can tell me what kind of flow overflow boxes have with different size holes?

[parkinsn]

If you have 2 holes i would use them both. Your going to have to buy 10' of PVC, glue and primer anyway so why not use it?