? about the diy overflow
- Thread starter eh1421
- Start date
I found some 1" plastic PVC pipe hangers @ Lowes (electrical section by the PVC conduit). They snap around the 1" pipe. They are normally attached to wood woth a screw or a nail. I used double-stick tape and stuck them to my aquarium frame. My overflow hangs on the tank so the weight is supported there. I use the PVC hangers just to stop any side-toside movement.
Excellent sticky, attested to by the fact that's it's still going after 7 years!
After reading it thoroughly a couple of times I have some comments and questions.
I am setting up a low-flow continual drip auto water change system on my 240 g SA cichlid tank with a pvc overflow Input (3-4 g/hr) is spring water so no chlorine/chloramine concerns. Output will be into my 1,200g aquaponic tank for evaporation makeup.
Seems like there are 2 applications discussed in this thread: 1)high-flow recirculation to sump and 2) low-flow drip for WC. The only difference it seems to be pipe size.
There also seem to be 2 basic designs: 1) surface skimming and 2) deep draw. Tank water level is determined by the inlet pipe (skimmer) height in #1 and by the discharge tee height in #2. Both require a siphon break at the upper discharge "U", either a standpipe or a drilled hole. I am unclear why the standpipe needs to expend above tank height. Noise suppression?
If I have this right, my plan is to install a 1/2" pvc deep draw design. Benefits of surface skimming will be negligible at this flow rate and a single pipe will reduce clutter in the tank. I will add a compression fitting/repair coupling on the outside riser to the discharge tee as a means of easily adjusting tank water height, a drilled hole for siphon break, and a check valve for priming.
Questions:
- Are my assumptions above correct?
- Is 1/2" pipe sufficient for this flow?
- Does the depth of the inlet pipe matter? I assume it would need to be deeper than I would draw the tank for a major water change to prevent siphon loss, but even that's easy to correct via the check valve.
- Does the level of the outside "U" matter, as long as it's lower than the inlet pipe?
Thanks!
Gordon
After reading it thoroughly a couple of times I have some comments and questions.
I am setting up a low-flow continual drip auto water change system on my 240 g SA cichlid tank with a pvc overflow Input (3-4 g/hr) is spring water so no chlorine/chloramine concerns. Output will be into my 1,200g aquaponic tank for evaporation makeup.
Seems like there are 2 applications discussed in this thread: 1)high-flow recirculation to sump and 2) low-flow drip for WC. The only difference it seems to be pipe size.
There also seem to be 2 basic designs: 1) surface skimming and 2) deep draw. Tank water level is determined by the inlet pipe (skimmer) height in #1 and by the discharge tee height in #2. Both require a siphon break at the upper discharge "U", either a standpipe or a drilled hole. I am unclear why the standpipe needs to expend above tank height. Noise suppression?
If I have this right, my plan is to install a 1/2" pvc deep draw design. Benefits of surface skimming will be negligible at this flow rate and a single pipe will reduce clutter in the tank. I will add a compression fitting/repair coupling on the outside riser to the discharge tee as a means of easily adjusting tank water height, a drilled hole for siphon break, and a check valve for priming.
Questions:
- Are my assumptions above correct?
- Is 1/2" pipe sufficient for this flow?
- Does the depth of the inlet pipe matter? I assume it would need to be deeper than I would draw the tank for a major water change to prevent siphon loss, but even that's easy to correct via the check valve.
- Does the level of the outside "U" matter, as long as it's lower than the inlet pipe?
Thanks!
Gordon
The standpipe is high for safety, so the system cannot flood on the floor. You must have an air vent and keeping it high is safer this way. It will function with the lower standpipe.
Gurgling noises are largely a function of how far the water drops between the normal tank level and the outflow T level.
1 inch drop is generally quoted as desirable but I typically use a bit more.
1/2" will flow enough for you. It can clog easily too, so I use larger. If a snail can plug it it's too small for me.
If the inlet pipe extends deep into the tank and your air vent plugs, the entire tank can siphon down to that level. This can happen when a snail siphons into this, system but not out the T, and instead floats up to plug your standpipe.
The external U must be below the T, the T must be 1"+ below nominal tank water level, and the inlet can be almost anywhere it cannot suck air. Too close to the surface and it will suck air. That breaks the siphon.
I run mine down into the tank about 10in behind a weir (that controls my water level instead of relying on the tee fitting.)
This is one design I use, with a fat black 4" ABS standpipe. It stands on my table instead of hanging on the tank. If a snail etc goes "over the top" it floats up and can never plug the standpipe
I glued my "T" into being. Outside is a 1" Union, inside a downturned elbow to suppress noise (search "Herbie vs Durso)
I have a clear 1.5" PVC P-trap for a "U" tube and it just hangs in the standpipe and weir. I can see the flowing water. Normally tank level and standpipe level are equal, but in the pic I had just started the siphon and I was flowing the max rate. This depresses the standpipe level until the system stabilizes.
The weir is white PVC which I heat formed and glued to a plexiglas base. I heated the end and "funneled" the top. By using a 2" PVC weir with a 1.5" PVC DRAIN PIPE (not thick wall pressure pipe like sched 40) it flows fast, but just through a thin slot. the black 1.5" is glued to the clear trap each end to make a "U". Notice that the standpipe must extend above the tank.
It doesn't need to extend above the "U"!
When I buy a bigger tank, it wilI cover the stand's top so I will order it bottom-drilled 2x, then drill my stand to match. All the plumbing you see will vanish.
This is how I hide it now. Fake Ivy.
I glued my "T" into being. Outside is a 1" Union, inside a downturned elbow to suppress noise (search "Herbie vs Durso)
I have a clear 1.5" PVC P-trap for a "U" tube and it just hangs in the standpipe and weir. I can see the flowing water. Normally tank level and standpipe level are equal, but in the pic I had just started the siphon and I was flowing the max rate. This depresses the standpipe level until the system stabilizes.
The weir is white PVC which I heat formed and glued to a plexiglas base. I heated the end and "funneled" the top. By using a 2" PVC weir with a 1.5" PVC DRAIN PIPE (not thick wall pressure pipe like sched 40) it flows fast, but just through a thin slot. the black 1.5" is glued to the clear trap each end to make a "U". Notice that the standpipe must extend above the tank.
It doesn't need to extend above the "U"!
When I buy a bigger tank, it wilI cover the stand's top so I will order it bottom-drilled 2x, then drill my stand to match. All the plumbing you see will vanish.
This is how I hide it now. Fake Ivy.
This is another siphon-overflow system I built. The weir is ugly but it was experimental.
