[MrScuito]

I want to add a 20 gallon sump/ref to my 29 gal but dont want to drill my glass can I use a back filter and tap the bottom of the filter and add a valve to regulate flow and gravity feed to the sump then use a return pump with a spray bar for return?

If there is no major reason why I cant/should'nt I think it would be a cheap and easy solution for me to add a sump.

 

[Jadinop]

It will not work. You cannot match the drain and return pump together for extended periods. Sooner or later one will slow down and either the sump or tank will overflow.

A true overflow system is controlled by only the return pump. However much water goes up is how much comes down the drain. As long as you don't exceed the drain capacity, it can't overflow.

Good pics and info here on sump basics.
http://www.melevsreef.com/what_sump.html

 

[hng]

I agree, it will be very tough to match flow rates using a hang on back filter. You can use an overflow box with a siphon, but you have to check it often to make sure you don't lose the siphon (no flow out but return pump keeps going).

 

[Loverotties]

+1

 

[MrScuito]

so are there any good cheap DIY overflows for a 29 gal DT to 20 gal sump/fuge?

 

[hng]

If you can't or don't want to drill the tank, then a siphon overflow is really the only option that I can think of. Some people never have a problem with them, while others have them fail often. Definitely something you should check often if you try it.

 

[Fat Tony]

Check out the Eshoppes line at one of the major carriers, Dr Foster and Smith or Marine Depot. The design you want has a U-Tube and is not the acrylic baffle type that you use and aqualifter pump with.

 

[Osurac]

One tip I am using in my temporary setup till I can drill my tank is to use a piece of airline hose to suck any potential air out of the siphon. All it takes is a hole in the top of the inverted U with the airline stuck in it. The hole should be 7/32. The other end of the airline goes in your sump.

This becomes a siphon of its own, sucking any bubbles out of the top of the siphon.

I also like that when I have to shut down the return pump, or remove the siphon for cleaning, the airline makes re establishing the siphon super easy. All I have to do is wait till the water level is high enough, suck a little air out of the airline, then return the end of the airline to the sump.

 

[Mock]

Check mine out.. It works...

I just posted a link to my youtube vid of my tank in the DIY forum main page.. and if you look on my page you will see the DIY overflow I made for my 75 gallon... Might help