Overflow box bubble!

[newsalt16]

I have a 54g tank and i made an over flow box and sump for it. As the water in the tank crests the edge of the overflow box i get little air bubbles and they float up to the top of the box and eventually (like with in a day or two) i loose my syphon. Does any one have this problem or know a way to fix it? Thanks for any help.

 

[hurt]

Two options, first you can raise the drains on the outside overflow box, so the water doesn't drop as much on the box inside your tank. If this doesn't stop the bubbles from entering your U-tube, you need a bigger return pump. The reason the air bubbles are collecting at the top of your U-tube is due to your flows not being matched.

 

[thangbom]

your U tube is not shyponing water to the outside box fast enough.. thats why air is building up in the tube... ( this is why 'hurt' said you need a bigger return pump.. it may speed the over flow speed up ridding of the bubble but, can your overflow handle that much water?? if you pump more then the overflow your pump may run dry ) maybe enlarge your piping on the outside of your overflow ( the piping that leads to your sump)
YzGyz

 

[earlybird]

Before you buy a new return pump what size is it? I have a couple of easy fixes that you may have overlooked.
Is there a constant bubble in your U-tube? IF so it isn't working to its full potential. Insert airline tubing and suck that bubble out. Very important on siphon start up that there be zero air in the U-tube from the beginning.
Is your box too high? The box in your tank with teeth might be to high. Make sure there's a good 1/2" or more between the bottom of the U-tube and the box. Could be an obstruction if it is any less. And it could just be that you need to turn your U-tube to correct for this.

 

[mudplayerx]

I had your problem and I just recently found the solution. First of all you have to balance your pump (via ball-valve) to where the current in the u-tube is great enough to flush all the bubbles out.
The second part is key. You have to be religious with your topoffs. If you arent, the pump sends microbubbles into the tank periodically, and those gather in the u-tube.

 

[newsalt16]

Thanks for all the replies!
Earlybird- i have a 550 g/hr pump and how would i turn my box?
I dont understand how having a larger pump will solve the problem. I am not disagreeing by any means, but this has been a learning experience for me so i am trying to unerstand all this. Here is a little background on the project. I got the dimensions for the box off of another website so i think that part is good. The bad part is it's a 54g corner. I bought a 20g as a sump but it didnt fit under the tank. SO i had to go with a 10g. I had to make the return side of the sump pretty big in order to not pump that side dry. In order to do that i had to shrink down the inflow side. Thats just a little more detail about it all. Thanks for all your help keep suggestions coming.
P.S. I have 1/2 pipe coming out of the overflow box i think somebody wanted to know that.

 

[hurt]

Your flows are definitely not matched if you are getting air bubbles in the top of the U-tube. That is the only reason bubbles will accumulate in the top of a U-tube. If they were close to being matched, the bubbles would be forced all the through to the outside box, and thus never accumulate at the top of the U-tube, which will break your siphon.
You just don't have enough "UMPH" to make it all the way through. Can you post a pic of your overflow box? I am assuming you have a 1in U-Tube(600gph), and do you only have one (1/2") drain to your sump? You may be able to go buy a smaller U-tube(3/4") to solve your problem. I just need to know the specs on your overflow. Also to let you know, your return pump is most likely not returning close to 550 gph, unless you have an external pressure rated pump(which you may). If you don't, most likely you have an "actual return" of around 400 gph. If you do have a 1in U-tube(600gph)-this is where the discrepancy lies(600-400).

 

[newsalt16]

I do not have an external pump (i believe that it what you called it) but i was told by someone from this site who has helped me alot that for each turn in my return line it would loose 5 g/hr. SO i thought i was running somewhere like 525 or so. I dont understand how i could change out my U-tube which i think is the part that holds the syphon. My box is only three pieces of plex. The whole center part is one piece of bent plex with two side and a baffle. So i guess thats four pieces. In the photos i used silicone but i have since taken it apart and used weld on. That was a good switch!!!! Hope these help!!

 

[hurt]

5gph for each turn, seems very low to me. Even at that, you have to account for head height in addition to T's, 45's, and 90's. Look at the back of your pump, it should show what the pump does at various head heights. For instance, my return pump does 1050gph at 0 head height. At 4 feet it does 750. I have it plumbed through a SCWD as well, and only one 1" U-tube in my overflow(600gph max flow). So I know for a fact that my 1050 gph pump does not have an "actual return" of more than 600gph to my DT.
That being said, you have no U-tube. You have a CPR style overflow. I'm not too familiar with those, but I believe you will need to buy an aqualifter.

 

[newsalt16]

Originally Posted by Hurt
5gph for each turn, seems very low to me. Even at that, you have to account for head height in addition to T's, 45's, and 90's. Look at the back of your pump, it should show what the pump does at various head heights. For instance, my return pump does 1050gph at 0 head height. At 4 feet it does 750. I have it plumbed through a SCWD as well, and only one 1" U-tube in my overflow(600gph max flow). So I know for a fact that my 1050 gph pump does not have an "actual return" of more than 600gph to my DT.
That being said, you have no U-tube. You have a CPR style overflow. I'm not too familiar with those, but I believe you will need to buy an aqualifter.

I cant find anything that says what gph it does at certain heights. Sorry. What is the difference in a CPR style overflow and what u have. Could u post some pics so i could see what yours looks like. WHat is an aqualifter and what does it do and how much does it cost? Thanks for all your help.

 

[newsalt16]

I did some looking and i found out that your right i do have a CPR overflow box. Thats where i got the dimensions. I also read that lots of people have trouble with the air bubble in this type of overflow box and i found out what an aqualifter is and how much it costs. Basically i answered my questions but i would ike to see a picture of your overflow box and i would like to know if you DIY or just bought it. Thanks!!!

 

[earlybird]

Sorry to confuse you in my post I thought you had a simple style OFB with a U-tube and two boxes one in and one out of tank.
I do know that those CPR style require an air pump to keep the flow going.

 

[newsalt16]

No problem!!! I am easily confused since i dont know much about these. Could you post a pic of your set up so i could see it. Do u think my style of box is bad?

 

[earlybird]

I like the concept behind your OFB and the style of CPR but I don't like the seperate pump needed to run it.
Mine is similar to this

 

[newsalt16]

Thats an cool setup, thanks for the photos. What do u mean by a seperate pump? U still have to pump the clean water back in your DT right? I dont know if you're allowed but can u give me the manufacturers name for that style of sump.

 

[frankthetank]

That looks like an ESHOPPS overflow box. I have one too.

 

[earlybird]

Originally Posted by newsalt16
Thats an cool setup, thanks for the photos. What do u mean by a seperate pump? U still have to pump the clean water back in your DT right? I dont know if you're allowed but can u give me the manufacturers name for that style of sump.
Sorry what I meant was that the CPR overflows require an air pump "bubbler" to keep the siphon working. The style above uses gravity and physics.