My new DIY PVC Overflow loses siphon on power outage.

[minerman]

I just put together a new sump system today, completely DIY.... I've never done this before and it's not working quite right.

I have a U PVC pipe for an overflow. It has a cap on top with holes drilled in it. When the water level drops below the cap holes (power outage) the overflow loses its siphon and needs re-primed each time. What have I done wrong? How can I make it keep its siphon for when the power comes back on so that I don't burn up my return pump?

 

[robbrouse]

Here the one I used on my 56.. It's been sold (than tank) to a family member, but it still kicking..

HOW TO: DIY Aquarium Overflow - YouTube

 

[minerman]

This is really depressing... I've done exactly this and no luck. I actually went out and upgraded from 3/4" to 2" PVC and rebuilt the system. The only thing I didn't have last time was the line with the cap up on top.

Not only do I have to reprime it every time... also I cannot get the maximum flow out of my pump. I bought a 950 gph pump and even with a 2" pvc return, I have to throttle down the pump with a ball valve or it will run my sump dry...

Wow...I just walked away to write this message and my overflow drained the tank all the way past the collection cap, down to the bottom elbow of the overflow piping, flooded my sump container.

I think maybe just the quality of my work is bad? I guess? I followed the instructions with the PVC glue, but it is clearly leaking.

 

[minerman]

I use no check valves in my assembly, but I don't know why that would matter if I plug the siphon hole an keep everything air tight.

 

[AZDesertRat]

Photos?

 

[minerman]

I also don't have the U at the bottom of my return? I just have a tee going straight down and then back up...

 

[feh]

I just put together a new sump system today, completely DIY.... I've never done this before and it's not working quite right.

I have a U PVC pipe for an overflow. It has a cap on top with holes drilled in it. When the water level drops below the cap holes (power outage) the overflow loses its siphon and needs re-primed each time. What have I done wrong? How can I make it keep its siphon for when the power comes back on so that I don't burn up my return pump?

When power is loss the siphon should break. You want this. Otherwise your sump will overflow and make a mess. When the return pump powers back on it should restart on its own though.

 

[robbrouse]

I know on my the T I was using in the back had to be higher the the lower part of the the that was in the bottom on the tank. I never got great flow with mine as well but did not loose the siphon. Power goes out it started up every time. If I stall had it I'd take photos for you. Like AZ said post some photos maybe we can help.

I hated a lot of thing about the DYI set up but it did work...

The check valve will keep are from going back into the pipe will only let it come out.. Mine did not work with out it.

 

[minerman]

 

[minerman]

When power is loss the siphon should break. You want this. Otherwise your sump will overflow and make a mess. When the return pump powers back on it should restart on its own though.

Yes, it does break like it should, but it does not restart. So, when the power comes on, my sump will go dry and it may damage my return pump.

 

[robbrouse]

Looks like to me yours is not going deep enough into your display tank. Mine was just like the one in the video other than I epoxied my check valve in and ran a tube from there. If you redo it like the video I bet it works

 

[minerman]

Looks like to me yours is not going deep enough into your display tank. Mine was just like the one in the video other than I epoxied my check valve in and ran a tube from there. If you redo it like the video I bet it works

Wait.... if you had it very deep in the tank, wouldn't you flood your sump if there is a power failure? I have mine so that the water level is just above it when everything is running.

My best guess on where I've gone wrong is that I must have an air leak somewhere. When the tank level goes low, it must be sucking some air into the pipe somewhere else, breaking the siphon. I know I had the cap on the back not glued. So, I glued that. All the pieces are glued but I am still having the problem. I guess I will try the check valve tomorrow but I don't have much confidence. I still am puzzled why with a 2" line, I can't return what I can input with a 3/4" line...

 

[robbrouse]

The u shape in side the tank went down further. The top was resting at the water lever I wanted to keep. Mine was 1" pipe made just like the video.. On your it looks like pipe inside the tank is not very far down.. Do you have the U shape on the front and the back?

On mine it went down to the bottom of the inside as well as the same distance on the back of the tank. I can really tell from you photos? If it's not a solid glue job and any air gets into the pipe it will not start up again.

Good luck and keep us posted.

 

[racer14j]

I have used an overflow like the video for about two yeas with no problems since I started the siphon. I made one change, the u inside the tank I used a larger tube with a cap at the end then glued the tube after the u to the inside of the cap. It works the same but you only see the one lager tube in the tank. In the pic it looks like the t is on the wrong side of the u and the cap with duck tape on it needs to be open.The u on the out side of the tank keeps water in the overflow. when the tank fills up water fills the rest of the overflow forcing the water in the last u out the t to start the overflow. The tube with duck tape on it brakes the siphon when power goes out when its plugged it will suck all the water out of the over flow loosing the prime. The check valve is needed in the u on the top to prime the overflow. With out it the over flow could still be primed but air will get trapped in the top u slowing water flow way down. From what I have seen the longer the tubes in the dt the more flow you will have, because the water flowing in and down helps with water pressure. I have also found on my overflow that using a level on the back tube before the last u will help get the most flow out of it. I assume that the cap on the inside of the tank is to keep the critters out. If that it is the case you might try using a tube taller than the water level in the tank and cutting small teeth into the top of it. The water level is set just above the bottom of the teeth. That will stop stuff from getting in that way, and if a tooth gets clogged the water level rises a little but the overflow still works. If you still have a shortage of water from the dt to your sump running a t with a ball valve on the return will let water back in to the sump to make up the difference in flow. It may not be ideal but it is a lot better than just using the ball vale by its self. When the power is shut off and the water drains into the sump it might not be from the over flow; if the return is lower than the water level the return line will also siphon in to the sump. If that is the case there are two fixes installing a check valve in the return line or moving the return above the water. I prefer the second because check valves get clogged. I know this is a lot. diy can be a pain when its not working but stick with it. its totally worth it in the end. If it will help you I can post pics of the overflow I am building for my 75 later this week.

 

[Eric Overton]

There are some things that I've learned about my recently installed overflow. It lost siphon the other day after working well for a few weeks.
1. Since I have a PVC overflow and an overflow box working together I had to increase the flow so that the overflow could take a fair share of the flow. I'm a little nervous about running the pump full blast for fear that the DT might overflow if one of the overflows fail.
2. I lowered the overflow box so that the PVC overflow would take in more. I could have also cut about a 1/4 inch off of the pipe.
3. I put a temporary plug on the check valve since it started letting air in.
4. I put a sink strainer to keep fry, plants, and food from getting sucked in and to quiet things.
I hope these work. How many of you are using multiple overflows? Two PVC's or one of each type?