Canreef Aquatics Bulletin Board - Why I'm ditching my herbie style overflow

Quote:

Originally Posted by 2pts (Post 741970)

I use a herbie system on my 6' tank.

Here are my particulars...

Tank has dual corner over flow boxes, both double drilled. Left side, I use one hole for my return pipe. Right side has my emergency drain.

Both sides submersed drains are plumbed exactly the same, same fittings, same length of pipes, everything. Under water they both have a 6" threaded pipe that connects to a threaded 1" tee. The tee has one 1" strainer horizontally, one 1" strainer vertically pointing up, the bottom is threaded into that 6" pipe.

Underneath the tank, all pipe is measured so that my true gate valve meets exactly in the middle. I did this so that the force of gravity from each side would be the same.

Height was a problem with my setup. My gate valve is actually lower than the top of my sump which sits on the floor of the adjacent closet. This means the draining water must travel up about 5" of height before draining into my sump. Both the emergency drain and the gate valve line are on seperate drain lines into the sump. Because of the height, I have to ensure my emergency drain always has a trickle of water moving through it, otherwise the water sitting in the dip would go stale and bad.

Because I am already slightly taxing my emergency drain, I use a fairly weak return pump. I have fully closed the gate valve to test the capacity of the emergency drain, which it handled.

I should add I use an ATO, but my sump system is 90 gallons total, when the ATO shuts off, the sensor is NOT fully submersed under water.

It sounds like you did it right, but I think yours is the only case in which it works the way it's supposed to when you've got two drains feeding one pipe. If I read this right, you only have one gate valve for both overflows, and the water travels the exact same distance on either side to get to it. In my case, having the gate valve in the dead centre wasn't possible without sacrificing most of the functionality of my sump (height was an issue for me too, and I needed the clearance in the middle), so everything meets on one side. Interestingly though, the distance the water has to travel to the join in the pipes doesn't seem to affect much, all that happens is that one overflow will be totally full, while the other will be a few inches lower. Sometimes it's the south end that's full, sometimes it's the north end, it's not that the end with the short pipes is always full or vice versa.

I'm not saying its not possible, (I've been doing it since April), but it's been more work than its worth to keep it functioning properly. I would do a herbie on a smaller tank, or a tank with independent overflows, but not again where the overflow pipes connect to each other before the reach the sump.

The problem with the ATO system is a separate issue from my plumbing, and I'm sure most people won't have that problem. It's just a weird case in which I need a powerful pump to get water up from the basement, and the return chamber is small enough that the pre-programmed settings on the Tunze mean that it will always fill a little more than it needs. In this case I would need to redesign the ATO system to function within the 'rules' of the herbie (weaker pump, throttling the output or what have you), and considering how poorly it functions with my plumbing anyway, I'm not willing to do that.