When a return pump dies or power is lost AND the top end of the return pipe is below water then water will start to flow backwards down the return pipe because a siphon is started (back siphon)..
That siphon will continue to flow until air is introduced into the line thus breaking the siphon..
The ways to introduce air are
#1-Anti-siphon holes which are holes drilled in the return pipe at/just below the normal surface of the water in the display tank
#2-Keeping the outlet of the return pipe in the display tank at or near the surface of the water
#3-A check valve in the return piping (this check valve is prone to fail and not recommended)
#4-Some other siphon break system..
You should leave some room in your sump for the overflow (back siphon) amount of water that will drain back..
If you take care of that then No you won't have a flood.
Make sure your sump has proper sized baffles so incase your overflow fails then your main tank won't overfill and cause a flood. Baffle the return pump area in the sump to be very small and most sumps are built with small return pump area.
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.