Nice Cheap DIY Overflow

[serotonin]

I made one of these identical to the authors image with 3/4" PVC and it was capable of about 10 gph

Going to try with 1 1/4" tonight and hope the reason it didn't work was due to the diameter of the PVC.

[Covey]

Had a guy in my local club make one out of 3/4" it didn't move much I was thinking it was more around 200GPH but it workec for his nano.

How much water were you wanting to move?

[serotonin]

I have a 90 gal setup so id like to turn over 500gph at least. I bought some 1 1/4" and built an identical setup to the 3/4" I made. I must say the 3/4" was like a trickle system. But the 1 1/4", WOW, that baby moved a gallon of water out of my test in the tub in just a few seconds. It's kinda fun to watch it work !

[VibeAUS]

Can someone tell me if the Air valve is realy neccesary. I just finished making one of these without it and it works great!!. I have not been able to find an air valve anywhere here in Sydney that is like the one needed.

Whats the impact of leaving it out?

[serotonin]

There is a posiblity of an air pocket building up there over time. However, if your moving water through the overflow at a good rate, the bubbles will more than likely be carried down and out the overflow. So to answer your question, no they are not completely necessary. But there is a good convienence factor there if your worried about the bubble build up business (holy b's). Other than that, it helps prime the system when you start out which is handy, but again not necessary.

[Covey]

What he said.
If you can't find a valve you can also use a piece of rigid airline and piece of flexible airline. Cement the rigid airline in place then and a small piece of flex airline to it. When you need to prime it start a loose knot in the flex airline. When the overflow starts tighten the knot and add a second for good measure. It is the setup I have on the original overflow right now.

[papa_otter]

Hey all, I just got around to my second try at building one of these. It is made exactly like the diagram. I still for the life of me cannot figure out how to prime the sucker. Maybe one of you could explain it to me as you would a child. Cuz thats how I feel after so much time working on this with no success.

[serotonin]

Cover all holes accept the one on the tank (underwater hopefully) and start sucking through the check valve thats on the uppermost U joint. You may need help with this (prolly will).

You can also start the whole process easier by drawing air out from the topmost pipe that is open, while the bottom hole (the one by the sump where the T joint is) is covered.

[papa_otter]

So you are saying you dont have it connected to the sump when priming? and if that is so wouldnt water go everywhere when the siphon started? Im so confused...

[sweden]

Originally Posted by papa_otter

So you are saying you dont have it connected to the sump when priming? and if that is so wouldnt water go everywhere when the siphon started? Im so confused...

ofcourse there be water everywhere if you dont have it over the sump