Thinking of Replacing Dursos with Herbies

[Itchy Trigger]

I know this has been covered in great detail and I've read a bit about it and think I could install Herbie drains in my tank fairly easily. But I just wanted to run it by you folks to be sure...

My tank is 550 gallons - 10 ft x 3 ft and 30" tall. There is a lot of water moving through the drains and the noise is a little too much for my taste (and way too much for my wife's). There are three overflow boxes, each one contains two drains and two returns. So it would seem all I'd have to do is pull the top pieces off of all six dursos, cut one of the drains in each overflow box down about 6" and cap with strainers, and leave the other as it is, open at the top. And add a gate valve to the drain pipe under the tank... Is it really this simple? Am I missing anything?

 

[kharmaguru]

Yes exactly.

 

[Itchy Trigger]

OK, I just realized a potential problem with this idea... I've got three 3750 gph pumps running on the tank, so I imagine I really would need all six 1.5" drains going. The Herbie system would only give me three (with the other three as emergency backups), which would mean I'd have to cut the flow way back...

 

[kharmaguru]

The gated drains become full siphons which flow way more water. I'm sure there's a flow calculator on the web somewhere..

 

[Itchy Trigger]

The gated drains become full siphons which flow way more water. I'm sure there's a flow calculator on the web somewhere..

Interesting. I'll have to see if I can find a calculator, but that's encouraging. Thanks!

 

[asmodeus]

oh your fine you have the 500 plus, I am the bored itch what can i modify hahhah


ok it was a good one

 

[Vinny Kreyling]

How Much Water Can Flow Through A Pipe (GPM/GPH)?

Three tables to get a general understanding of water flow capacity through a pipe or roof drain. If you have questions, contact our roof Drain Wizard.

resources.hy-techroof.com

 

[Itchy Trigger]

One more question. I've got three gate valves arriving tomorrow. I'm planning to do the first drain either tomorrow or over the weekend, and then do the other two next week. So I've read that the gate valves should ideally be positioned vertically under the tank. Unfortunately due to space limitations that won't be possible on my setup. Is that going to be a problem or should I be ok with the gate valves in a horizontal orientation? I just want to be sure this is going to go as smoothly as possible since the tank is running with fish and a mature sump...

 

[kharmaguru]

It'll still work. The issue is purging air after a power outage - they may gurgle for quite a while and thus not be full siphon till they purge. I would keep the horizontal portion as short as possible and as downward angled as possible. For elbows can you use 45's instead of 90's and fit in your space?

I'm actually more curious how you are going to shorten the pipe inside the confines of an overflow box.

 

[Itchy Trigger]

Thanks. The only long horizontal run is the drain for the right overflow box, which has to travel the length of the sump to enter on the left side. The middle one is pitched downward by about 25 degrees for about a 4 ft run, and the left one drains right over the entry to the sump. I'll take a look today and see if I can somehow pitch the right one a little more with 45 degree elbows. Because of the way I ran the pipe though, the only places I have room to cut for gate valve installation are in a horizontal (or nearly horizontal) orientation. The stand is fairly short, so space between bottom of tank and sump is very tight. It was a bit of a nightmare doing the plumbing on it first time around.

As for shortening the drain pipes, I won't need to do that within the overflow box - I'll pull them out and cut them. They aren't glued in - just friction fit.