Nah, I'll let you figure it out by trial and error. :)

Ok find, here are some of my suggestions:

If your overflow siphon breaks and it stops draining water from your tank. Now your return pump is going to empty the return section of your sump into your tank. So make sure your water level in the tank, and the size of your return section, are matched so that the tank can "absorb" the water from the return section of the sump, and you won't flood. You will burn out your pump though.

If you want to avoid burning out your pump, install a float switch to detect a low water volume, and cut power to the pump if the water volume is too low.

Are you using a CPR style overflow box, or a u-tube design? Make sure each end of the u-tube (if you are using that style) remains submerged in water in the event of a power failure, and restarts when power comes back on. This is easy to simulate.

Also basic maintenance is important, make sure to keep the overflow super-clean and algae free. Also a snail guard is important, use plastic mesh or similar.

And on your next tank, get it drilled like swiss cheese.

sump
 

Best suggestion go here http://www.melevsreef.com/ and read it's a great place to start

normal PVC Cement and primer works fine of flex SPA pipe. mine has been holding for 3 years now and still strong, just make sure you do the primer and use a medium or heavy body glue.

Steve

I am not using the CPR overflow. The tank is drilled for an external overflow.

Searched online a bit before and talked to a couple of Hot Tub places and just ended up gluing my SpaFlex as well with regular PVC cement and primer.

A few thing you should keep in mind.

You will at some point want to take it appart. Use "Unions" in logical spots so that you can remove sections of the plumbing.
If your sump will be located right below the overflow, there is little need for Spa Flex. Save your move and just do it with regular PVC. Or upgrade from Sch 40 to sch 200. it is thiner walled high pressure.

You will want to put a ball valve just after your pump to regulate the amount of water returning to the tank.
Do a search for Derso stand pipe. That will be a great addition to the overflow as it will quite down the water drain sounds.

J

What do you mean?

Hard to explain haha. I will take a pic and post it tonight.

Alrighty. But basically the same potential problems still exist, because any overflow can potentially clog and fail.

Also make sure your return piping won't siphon your tank back into your sump when power fails. If you want your return low in the tank, then drill holes in the piping just under the water line so that when the water level drops from back-siphoning, it sucks in water and breaks the siphon.