Quote:
Originally Posted by
1guyDude http:///forum/thread/386283/overflow-question#post_3391933
So ive been thinking a lot lately about sumps and overflows. The more i read or here about it, the more i here of horrible floods~!
My question is how does one stop the flood if u lose siphon on ur overflow box or homemade DIY overflow? Obviously if the power outage hits than ur return pump will stop too but if u lose siphon are u just pretty much hosed?
For the most part overflows will hold the siphon when the power to pump is cut. So when power comes back on everything starts flowing like it should. Be careful with the diy overflows, some designs work good and others not so good. If everything is planned well, pump and overflow are sized appropriately then there's not much to worry about. Like Shawn mentioned, alot of floods occur when people aren't too familiar with running them at first and don't realize what's happening. There's a small learning curve dealing with your first overflow.
But a well planned set up is fairly safe.
Drilling is still a better way to go no matter what IMO. Priming an overflow and keeping an eye on it to make sure no air is building up in it or your aqua lifter pump is still working is just more of an inconvenience that you don't have to worry about when it comes a drilled tank.
Making sure you have enough room in your sump for back flow and building your return just right with a siphon break is really pretty simple, not much to it. You could get crazy and start calculating and plan to have your return chamber a certain size so that if your overflow ever did lose it's siphon somehow that the return chamber would be small enough that when it's pumped dry that it would never overflow your display tank. You might burn out your pump. But in this particular case it would be helpful to have your overflow set a little bit lower in the tank to allow the tank to handle an extra 4-6 or so gallons of water. Tangs Rule calculated it that for every 1" of water in your tank is just under 4 gallons. So having your water level in the tank set about an 1.5" from the top would allow for that extra water volume. If you go with a 20g sump then it shouldn't be that hard to figure out the size of your return chamber that you'd need to be on the safe side. Something like a 12"x12" return chamber with a water level 8" high would be right about 5 gallons minus the mass of the pump.
Lots of things you can do, just gotta get creative. Could maybe even throw a float type switch on the pump that will actually kick the pump off if the water level gets to low in the chamber.
