Over flow boxes

[couch702]

I am using an over flow box for my sump, which I'm sure many people use. I'm not a fan of them due to the fact that if the siphon fails then your tank will over flow. My question is, is there a way to prevent an over flow if the siphon fails? I'm not worried about power outage. I have a solution to that problem already.
The reason I ask is because I woke this morning and noticed big air pockets in both siphon tubes. I want to prevent that.

[Luke]

"drill baby drill" ?

[tomgl]

I have seen aqua lifters used with the overflow box. The lifter keeps the syphon going.

[couch702]

Can't drill, I wish that could!

Aqua liters??? Please do tell.

[Tlalok]

DRILL!!!!!!!!!!! im not an expert on this but if i would you i would find the way to drill ...

[Narazbad]

You are getting air pockets because the tubes are pulling water faster than your overflow box can deliver it. Cut back to one tube and you will never have an issue of it causing a flood.

[couch702]

The reason I can't drill, is the fact that I'm don't want to pull my tank apart so I can drill it.
I will try pulling a tube out and see how that goes, thanks.

[couch702]

Or..... Could I use a smaller diameter tube if its drawing to fast? You guys think that will work?

[tbone74]

I ran an overflow box years back and I thought they only pull the amount you put back. Slow your return pump down. The water is flowing into the box too quickly and the siphon is sucking up some air bubbles. I used a CPR box with an aqualifter attached to the siphon tube as tom described with no problems. You just need to dial it in a little with a valve on the return side of your pump

[Narazbad]

Siphons will pull their maximum ability as much as they can. Adding less water will just make it run out faster and have more issues.

[tbone74]

Siphons will pull their maximum ability as much as they can. Adding less water will just make it run out faster and have more issues.
Siphons do pull to their maximum ability, but a siphon overflow only siphons water to keep the water level of the box inside the tank LEVEL with the water in the box on the outside of the tank, that’s it. If less water flows into the internal box, the siphon slows down. your statement would be true if the siphon went all the way to the sump, but it does not. It only keeps the water level in the two chambers. Then it flows into a pipe down to the sump, not under a siphon. Slowing down the flow into the internal "box" will only reduce turbulence and reduce bubbles getting sucked into the siphon tubes. If you speed up the pump more air will be introduced by turbulence and the siphon will fail, and your sump in its entirety will be on the floor. Unfortunately I had to clean up 60 gal of saltwater off the floor because if this :(

[couch702]

Ok after playing with my return valve for a few hours I think I have it dialed in. There are far fewer bubbles in the overflow now. My siphon hoses both seem to be running flawlessly right now. I'm still going to look into those Aqua lifters though.

[Luke]

im trying to understand this...

i understand that the siphon is taking water out of the box...

if you slow down the return, then there will be less water in the box....

if theres less water in the box, and his siphon takes out too much water, then it will break right? or it will suck in air until the return pump catches up... right?

i dont see how slowing down the return is going to slow down the siphon...
i would think you want the water level in the overflow box above the siphon to keep air out.

[tomgl]

It been a long time since I have seen one setup. I believe the overflow needs to be designed to use it. If anyone is using one chime it.

[Luke]

i saw an animation of this once im trying to find it

[couch702]

Slowing down the pump won't slow the siphon, it will cause fewer air bubbles in the internal box due to the water falling and creating air, which in turn gets sucked up by the tubes, then they collect in the siphon tubes eventually breaking the siphon. So slowing down the return will have the water fall slower, creating less bubbles in the internal box.

Ha I sound like I know what I'm doing now because of the tread I just started. Lol you guys are great.

[Luke]

i cant insert the image, but here is the link:

http://reefkeeping.com/issues/2003-01/gt/images/overflow-dynamic-labeled.gif

i think i get what tbone is saying about the 2nd chamber

[St8Gr3]

Oh ask Gian... he has a really cool setup on his that woulld prevent that!

[tbone74]

Overflow boxes are really not a true siphon. There are two chambers and a u tube that connect them. The only purpose of the u tube is to allow the water level in the outside box to be exactly level to the water in the inside box. Water seeks a constant level.... The ends of the u tube are submerged in water in each box, and keeps the water in the tube. Turn off the pump and the water still stays in the tube. There is water in the u tube and it stays in there because the preasure in both boxes is exactly the same. If you add some water to the first box the preasure increases and "pushes" some water through the u tube into the second box to equalize it, now the water line in both boxes is again equal. If air gets caught in the u tube, the siphon breaks and the two compartments are no longer "connected". The return pump keeps pumping water into the aquarium (filling the first box) but the u tube is not filled, the tank overflows. But there is a bulkheat in the outside box just the same as a drilled tank. the water then flows from the outside box (NOT the u tube) through the bulkhead down into the sump

http://i980.photobucket.com/albums/ae288/tbone219/cpr.jpg
http://i980.photobucket.com/albums/ae288/tbone219/cpr2.jpg

The first pic is the box in the back, the second pic is the sponge removed and a durso standpipe is used. I hope this makes sence to everyone. When the pump stops, so does the siphon, when the pump turns back on, the siphon continues.

[Gyzpaz]

I did a little experiment with my Solana where i want to minimize the risk of flooding involving an overflow using siphons to go above the tank water level. Basically what i did was to bring the water level of the source almost to the tank water level. I did this by using the 2 chamber hob fuge i got from Chriss. Water goes in one chamber, flows over the divider and to the second chamber to a drain. So the first chamber is tank water level and the second of course has lower water level. Mirror this set up inside the tank. One chamber pumping water into the tank and tank water draining into the other. I used my built in Solana chambers for this. Now you got four chambers with diagonally proportional water levels. All you have to do is siphon high water level from hob into the tank and do the opposite on the other chamber. Sorry for the long post , but it works.

[Luke]

this is what i learned: it works because the siphon doesnt go allll the way down to the sump... it only goes to that second chamber... seems pretty simple now.

[kentlighting]

A float switch mounted in the tank and a relay to to connect your return pump to said switch . If the water I the display gets to high float will activate the relay to turn off the pump preventing more water going into the display.


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[couch702]

I think I'm going to look into the float switch idea.

[iap]

Buy extras float switches