pvc overflow keeps losing its siphon :(

roovy · 07/06/2013, 10:42 PM

hi guys! I'm really new to the hobby but i decided to jump right in and build a pvc overflow and drawer tower sump filter. you can check out the video i made here http://youtu.be/Hyr84QG7_gQ

everything was working fine, but every once in a while my overflow keeps losing its siphon. is my pump pushing out too much or too little water? i was thinking maybe the check valve is not working, but the overflow will lose siphon even when the check valve is still filled with water. i was thinking maybe i should put a tube at the end of the valve and then i could clip it off, so it stays tight. then i was thinking maybe i've cut too many or too few holes in my intake which is allowing too much air to get into it. I'm really lost, and can't seem to find any information online. i really appreciate any advice. thanks so much!!!

-Roovy

Pitter98 · 07/24/2013, 03:16 PM

I know this is kind of old now, but the design of your overflow isn't very good for being failsafe. What is most likely happening is your pvc overflow is pulling small amounts of air in that build up over time that eventually break the siphon. You need to have enough flow through the overflow to push the air bubbles down the four or so feet to your sump. You are likely not doing this as it would take quite a bit of flow to accomplish it. Most hang-on overflows just have a short tube that goes over the tank which is separate from the line going down to the sump. This allows for a lot less flow needed to push those air bubbles out of the overflow tube. The other option is to put an aqualifter or some other similar small pump on your check valve line to pull the air bubbles out.

My recommendation would be to either just spend the $30 or so to get a hang-on-back overflow that will work, or attach an Aqualifter to your checkvalve line to pull out the air bubbles. Neither solutions are foolproof, but they will be a lot safer than what you have now.

miatawnt2b · 07/25/2013, 12:34 PM

+1

Your siphon is too big for the flow.

07/06/2013, 10:42 PM	#1
roovy Registered Member Join Date: Jul 2013 Posts: 2	pvc overflow keeps losing its siphon :( hi guys! I'm really new to the hobby but i decided to jump right in and build a pvc overflow and drawer tower sump filter. you can check out the video i made here http://youtu.be/Hyr84QG7_gQ everything was working fine, but every once in a while my overflow keeps losing its siphon. is my pump pushing out too much or too little water? i was thinking maybe the check valve is not working, but the overflow will lose siphon even when the check valve is still filled with water. i was thinking maybe i should put a tube at the end of the valve and then i could clip it off, so it stays tight. then i was thinking maybe i've cut too many or too few holes in my intake which is allowing too much air to get into it. I'm really lost, and can't seem to find any information online. i really appreciate any advice. thanks so much!!! -Roovy

07/24/2013, 03:16 PM	#2
Pitter98 Registered Member Join Date: Apr 2005 Location: Troy, MI Posts: 115	I know this is kind of old now, but the design of your overflow isn't very good for being failsafe. What is most likely happening is your pvc overflow is pulling small amounts of air in that build up over time that eventually break the siphon. You need to have enough flow through the overflow to push the air bubbles down the four or so feet to your sump. You are likely not doing this as it would take quite a bit of flow to accomplish it. Most hang-on overflows just have a short tube that goes over the tank which is separate from the line going down to the sump. This allows for a lot less flow needed to push those air bubbles out of the overflow tube. The other option is to put an aqualifter or some other similar small pump on your check valve line to pull the air bubbles out. My recommendation would be to either just spend the $30 or so to get a hang-on-back overflow that will work, or attach an Aqualifter to your checkvalve line to pull out the air bubbles. Neither solutions are foolproof, but they will be a lot safer than what you have now. __________________ 150g DD Cube Mixed Reef w/ 2 MP40wQD's, a Jebao RW-15, black box LED's, a basement sump, and not enough fish.

07/25/2013, 12:34 PM	#3
miatawnt2b Registered Member Join Date: Jan 2001 Location: Tucson, AZ Posts: 1,467	+1 Your siphon is too big for the flow. __________________ Proud member of the JTCCB (jebao tuners club for cheap bastards)