Tying 2 sumps together with return pumps in both..please help

[77bandit]

So, I've mentioned this idea before and now I'm really scared after some responses. I can't remember from whom exactly. But, I would love to hear from any and all that have done this. Again, my stand is 10'x24"(interior width)x24-29"H(supports every 18"). Anyway, I want a sump w/skimmer at one end and sump w/refugium at the other. I would love to have my return pumps directly below my end overflows as tank is viewed from both sides. I would tie the 2 sumps together with 1.5" PVC as I'm sure the flow will be different through both although I'll have identical sumps w/identical pumps and overflows are identical as well.
Anyway, has anyone done this?
If so, results?

 

[halmus]

I understand the apprehension some people would have with this type of setup. I'm unsure whether a single 1 1/2" line would be enough to equalize water levels in both sumps. I would tend to go as big of a pvc line as you could fit in between the two. (2"?). Bulkhead size availability might dictate that. Or, plan on two lines stacked vertically.

The real test once this is up and running is: turn off one pump on one side and monitor the behavior. If the pvc line connecting the two sumps can't keep up with the water flow through the sump with the disabled return, you've got a problem. The sump might overflow. You need more volume (more PVC) connecting the two for easier equalization. Repeat the test on the other side.

If that test works, I don't see a major problem. Other tab ensuring the connecting pipes don't get clogged.

If everything is so perfectly balanced that you don't get much water flow in the pipe(s) connecting the two sumps, you could always direct some water from one of the returns to the other sump forcing an imbalance and creating the flow to prevent stagnation. I don't think that will be necessary.

I would use true union ball valves in line at each end of the connecting pipe to be able to isolate the sumps for maintenance purposes. And valves to stop up overflows. That way you could turn off one side of the tank for maintenance while letting the other run.

Just my opinion. Knowing the people in this hobby, someone will be along shortly to tell me that I'm stupid and contradict everything I've said.