DIY overflow

[krayzie]

ive been looking at melevsreef.com and he has an overflow thinging... i was just wondering what the piece of tubing sticking out of the top is for

here...http://www.melevsreef.com/29g/sump/weiriic.jpg

[Inflames]

to restart the siphon and keep it primed. You use an airlift pump on it.

[krayzie]

what is an airlift pump?

do u have to use one?

[Dubbin1]

airlift pump (http://www.marinedepot.com/md_viewItem.asp?idproduct=KTALP)

[krayzie]

http://www.marinedepot.com/IMD%5C150%5CKTALP.jpg

in the pic it has 2 holes for pipeing....

r they entry/exit holes?

[ErikS]

No, that would be two exit (air line) holes.

Do you have to use one? No, not it you don't mind water all over the floor.

Check www.lifereef.com for an example of a fail-safe overflow design (under pre-filters).

[krayzie]

couldnt i just put a airvalve on there..... and suck out the air manually?

[Levi_S]

Originally posted by krayzie
couldnt i just put a airvalve on there..... and suck out the air manually?

only if your home when the power goes out :D

[durango_doug]

yes, putting an airvalve on it would work fine. but i don't like the idea of trusting an airvalve. i just run mine to the venturi valve on my maxijet 1200, it's strong enough to prime it and keeps all the bubbles out. i even wired it to two maxijets just to make the priming process faster.

Levi_S:

why would a power outage be a problem with the air valve?

doug

[Levi_S]

Originally posted by krayzie
and suck out the air manually?

manually implies being there to suck on it, at least that is my interpretation. i can not see an air valve being able to prime itself. don't pay too much attention to me as i am going to attempt my first diy overflow/skimmer combo this week and i have <b>NO</B> prior experiance with this stuff. i am just very nervous about this siphon loss problem as i am in a second floor apt.

[ob1thx1138]

Really there shouldnt be a problem with it losing its prime unless air bubbles build up. Most of the ery few air bubbles that enter the system should move through it with the water flow.

As long as the water level stays above the end of the "U" opening it should never lose its prime, even if/when the tank level drops due to power outage..

[durango_doug]

that was my point, it wouldn't loose its prime. however, since there is so much volume inside the overflow chamber, there is not enough flow to eliminate the bubble problem. this type of overflow actually needs some sort device to constantly pull air and water out of it. even if the power heads you are using don't have a venturi valve, it is easy to make a one, just drill a small hole in the powerhead output and slap an air hose on there. it's just one less outlet taken up, and it's cheaper.