live rocks in the sump
 

I have a 77 gal reef tank and I just bought a used in sump protein skimmer. So I am well on my way in putting in an overflow box and a 33 gal sump. Then I am stuck on two questions:

1. Can I put live rock in my sump and how much water should I have in the sump?

2. For whatever reason, if my overflow is plugged, how will I prevent my return pump in my sump from overfilling my main tank?

Thanks...

Yes, you can keep live rock in your sump. Protect your pump intake with a guard.

The sump water level is sually enough so some evaporation can happen without causing low water problems with the pumps and not so high, that it allows the back flow from the tank to be easily handled, when power is off.

One problem with hang on overflows, is the one you fear. Thats the reason drilling is so much better. As I have never used one, Im not sure how to protect against it. Here is what I would think,

- make sure is a good make, with the constant overflow design and not siphon tubes.

- perhaps a high level float switch in the tank, that protects the main pump.