Will this sump/setup work?

[Beefy_Reefy]

If I have a strong enough pump will this work? Glass holes 700 overflow with 3/4 return kit on a 40g breeder. Nano kit with 1/2 return kit on a 20g long. On return, is it ok to go from 3/4" pvc to 1/2" pvc for the smaller return kit? With valves I will try to dial them all in so the flow isn't too great/poor.

2 30" stands.

Posted before but pictures were not working for me so I made a photobucket account. Preview seems to be working.

<a href="http://s1061.photobucket.com/albums/t474/Twobit311/?action=view&amp;current=c1458068.jpg" target="_blank"><img src="http://i1061.photobucket.com/albums/t474/Twobit311/c1458068.jpg" border="0" alt="Photobucket"></a>

[uncleof6]

Couple things:

1) Using the small diameter return pipes, will require a larger pump, than would be needed if you upped the return pipe size to 1" all around. This is due to friction loss, with the larger pipe being ~1/3 the loss of the 3/4" and much less than in the 1/2".

2) Remember that glass-holes drain systems are "air assisted" drains, aka dursos--the only difference being how the water and air enter the line. They are subject to the same physics and problems associated with durso stand pipes. The small diameter of the drain from the 20 gallon (1"), added with the horizontal run, are likely going to cause problems with that drain line. The smallest practical "air assisted" drain would be 1.25".

[Beefy_Reefy]

So you'd go 1" return lines and just control flow with valves?

As for overflow drain from 20g I'll have more of a diagonal angle on it.

[uncleof6]

So you'd go 1" return lines and just control flow with valves?

Well I would not setup a system such as this, however, I would definitely use 1" pipe at the smallest, and valves to control flow--in the return lines, no valves in the drains.

As for overflow drain from 20g I'll have more of a diagonal angle on it.

That will help, but you want to increase the pipe size to at least 1.25", to avoid drain issues.