Potential Overflow Problem

[sinkingbeach]

I have a 75gallon with a 30gallon long sump(new new system), after my sump overflowed yesterday when I turned off the electricity to the return, I shortened the return pipe in the main tank. I was unaware of the back flow into the sump from the return pump, totally through me off wasn't expecting it :eek2:
After playing with the syphon and losing syphon I've come to the realization that if I lose syphon but not electricity my main tank will overflow :hmm1:
My question is if I do not lose electricity but lose syphon, how do I prevent the main tank from overflowing?

Thanks
Francis

[Neurosis]

You should design the sump so that the return compartment only holds so much water. For example, if you do a typical three chamber sump (drain-->skimmer chamber-->fuge chamber-->return chamber) the return chamber may only hold say 5 gallons or so of water, typically not enough to overflow your main tank. As opposed to making the sump just one large chamber, whereby the potential of holding say 15-20 gallons of water (since it's one large return chamber) will definitely overflow the main tank. HTHs