Overflow not working

A

Aphyosemion

Reefing newb
I am trying to set up an overflow for my 40 gallon saltwater tank. I have a PVC piping overflow that I setup and tested in a big bucket in the bathroom and it worked perfectly. It is W shaped with the middle of the W hanging on the tank. It would stop when the water got low and as I filled the bucket it would start again and everything was great. Then I set it up on the tank and glued everything together, but like an idiot I didn't use the exact same length pieces. Now it will not work and I can't figure out why. Can anyone help me figure out the simple pvc overflow method? I originally had a web site that gave me the idea, but I can NOT find it again.

-Aphyosemion
 
Either upload them into the Living Reefs Photo gallery or onto a site like Photobucket, then paste the
 
Okay, here is a pic of the overflow. I managed to get one up and it will not let me post a second.

Overflow1.jpg


I don't know if the T is too low or too high or if one of the pipes are too long or too short.

-Aphyosemion
 
Okay, I uploaded the first pic of the overflow, but it won't let me upload a second. It repeatedly says invalid file, so I took another pic and tried and it still says the same thing. I have no idea why.

-Aphyosemion
 
It still won't let me upload a second file. If you look at the one picture I managed to get up though, you can get an idea of the setup. On the lower right is a T with one side going down to the sump and the other going up to the top.

-Aphyosemion
 
I've never dealt with a homemade overflow before. But the only thing I can think of as to why it's not working is that it's losing siphon somewhere. Are all your seals tight and air proof? Are you able to start the siphon, and then it just loses it eventually? Or can you not get it to start at all?
 
hmm not sure. but, if i were to take a guess i would say it's because the tee branching off to the sump is lower that the top of the pipe that's letting water in, causing a loss of siphon.
 
Okay,I'm a little confused?What am I looking at....is that the main tank or the sump?I'm going to assume thats the display tank for now.

The drain where the green screen is,why such a large and deep bend.How come it goes down behind the tank and back up again?
 
Well, the shape is based on a style I saw online for a basic gravity fed overflow. The first drop where the green mesh is, is where the water goes in, then it flows over the top and back up to the T. The pipe above the T is where you suck on the little air hose to get the siphon started. It is higher so you don't get a mouthful of water, which you sometimes do anyway. This style works great if it is set up right. The W shape holds water and when more water flows in the intake it starts flowing again. It worked great with the first 1" pipe I set up, but the new one doesn't. It just drains for a few seconds and then seems to lose suction and stops. It doesn't drain very fast though to start out with. The last one drained like heck and it was only 1" PVC.
Maybe the T needs to be higher than it is? The very first time I was looking for a way to set it up I found the style that I have now, but I haven't seen it again since. I thought it would be more common considering how simple it is, in theory. In practice I don't know which pieces are supposed to be higher and which ones are supposed to be lower.

-Aphyosemion
 
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I have never seen an overflow done quite like yours,similar but not the same.So,I'm going to play this by ear.

Wouldn't it be better if the bend was shorter,like way shorter?The bend back up on the outside of the tank....is that where you suck the air out?I see a glob of silicone and what looks like an airline tubing.To me,it just doesn't look necessary.Sucking the air out will only make water rise into that chamber.With the water being higher there than the drain will only stop the siphon.
 
That is where you get the siphon started in the first place. Then you plug the airline to keep the siphon going. I am really surprised that no one does it this way, since this is the first thing I saw when I looked.
I tried moving the T up a little higher and that didn't seem to work. I am now trying to make the outside of the W a little longer to see if that works. I might need to make both sides of the W shorter for all I know. Wish I could find that website again.
It is funny that this takes like 5 minutes to cut and put together and I have been trying to figure out why the second version isn't working all weekend. I wasn't even sure why the first one did work, it just did. :D

-Aphyosemion
 
Nope,I never seen it done like that.I've seen a tank drilled and the pvc glued to drain the water,Not hung over the lip and going back up to remove the air.the only thing I think will work if you made the piece where you suck the air out shorter.Besides that,I'm at a lost.
 
AHA!!! Okay, as it turns out when I made the outside of the W slightly lower than the inside of the W it suddenly works. I have no idea why, but as soon as I tried that it suddenly works like magic. WOOHOO! Now if I could just post an updated picture so you could see the difference between the working version and the non-working version. It is about 2 inches of PVC. :frustrat:

-Aphyosemion
 
Okay, it did the same thing when I tried to upload 2 pics again. It took the first one and then repeatedly says Invalid file for the second one. I don't know what the deal is.
Here is the first pic of the working version though:
WorkingOverflow1.jpg

I added a little silicone to make sure it holds a seal. What apparently makes the difference is the outside turn being lower than the inside turn. Now I can actually put something in that tank other than algae and some copepods.
I mentioned to my girlfriend how surprised I was that no one else is using this method and she said that now I get to see that there is probably a reason for that. I'll let you guys know how it goes.

-Aphyosemion
 
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