overflow

nacl-man

Member
no such thing as a stupid question :)
a HOB Overflow has two 'boxes' one inside the tank with little teeth to do some surface skimming, and one on the outside w/ two chambers. The first chamber on the outside stays full of water so your siphon doesn't break. The siphon is a 'U-tube' which sucks the water out of the display tank, dumps it into the first chamber of the outside box on the overflow, which in turn dumps it into the second chamber, which has a drain that drains the water down into your sump / refuge area.
It sounds really complicated, and I myself was baffled at how they worked, until I set it up. After I set it up I was all like 'whoa, that makes sense and is simple'. :yes:
Hope that didn't confuse you more.
 

ettienem

New Member
Thanx. It makes a litlle bit more sense. If anybody could post a pic of one it would be a great help. I have been to many FS and no one has them so I have to build my own.
 

robchuck

Active Member
gregvabch posted a picture of a CPR continuous siphon overflow. That style requires an air pump or a rejuvinating venturi powerhead to continually pull air bubbles out of the top of the box through a

[hr]
. They work well if they're kept clean, and if the power doesn't go out alot. I use one of these and like it very much, but you'll find other not so kind reviews on this overflow.
I've also attached a picture of a U-Tube style overflow. It's not an exact diagram of NaCL-Man's explanation, but it gives you the general idea.
 

seaslug0305

Member
hey that diagram you drew looks like the one i just got from a friend..its a little old but free so i could really care less..the only thing i cant figure out is that the u tube is hard plastic and doesnt bend or anything so im not sure how im supposed to get the siphoning action going...any thoughts?
 

gregvabch

Active Member
well, i've never used one of those, but i'm assuming all you gotta do is plug the supply tube with something, like maybe your thumb, and then fill both sides with water. then pull your thumb out and the rush of water should start the siphon. could be wrong though. i use a cpr overflow and my powerhead does all the dirty work for me :D
 

wannabfish

Member
What you need to do is buy yourself a small piece of silicone air tubing, and slide one end of it up into the u tube. then with the other end, suck which will draw water from the skimmer side to the overflow side of your overflow. sounds confusing, but it is really simple. if you need any more answers on this exact model, please feel free to email me with any questions you have, Hughesbob@hotmail.com.
Hope that helps
 

seaslug0305

Member
thanks for the advice..what i ended up doing was filling the tube up with water and ironically the lids to the milk cartons i was using to hold r/o water fit perfectly in the tube to block the water and ultimately get the siphon going.
 
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