Anti Siphon Question on Return

[hogsnapper07]

I'm going to be building my new acrylic tank and stand this weekend and have a quick question about how to prevent a siphon on my returns. The tank will be a 48"x28"x20"Tall 3/4" acrylic tank. I am planning on drilling a 1-1.5" hole drain on the back of the tank for the overflow as I have seen it done on a few other tanks and don't want to lose the space for an overflow box. My question is with the returns, I want to do 2 returns on the bottom of the tank near the front two corners that have a 45 degree fitting on it pushing water back to the top rear of the tank onto the livestock. I know that a simple way to prevent a siphon would be to put a check valve on both return lines but have seen them fail many of times. Is there any other way to prevent this siphon or any suggestions anyone has?

Also I need to find the pvc fittings that have the washers on both sides for the overflow and returns. I have gone to home depot and Lowes and they do not have what I need. Does anyone know where these can be found? I am basically looking for the fittings similar to what is used on the overflow box plumbing with the washers. I don't need that whole system as like I said I want to drill the 1" hole and have pvc that has a water tight fitting and then runs 90degrees down to the sump...

Thanks for your time and help

 

[johniii]

Dont know a way to stop the siphon. But you need bulk heads for the holes. You can get them online or a lfs near you

You could just run the return up top and use a closed loop pump for flow.

 

[hud3339]

Just use a check valve

Edit: Just use a check valve

 

[schwaggs]

I agree with the OP that Check Valves are doomed to fail eventually. I solved the siphon problem with my returns by running the return plumbing up the back of the tank's outside above the water level, then back down to the return in the back of my tank. I drilled and threaded a 1/4 fitting in the elbows at the highest level and screwed in a John Guest fitting with some 1/4 inch tubing to just below the water's surface. Works like a charm to break the siphon with limited back pressure (a few feet of pipe and 2 90 degree el's).

 

[grouper therapy]

I'm not sure how check valves fail with proper maintenance . What fails on them?

 

[hogsnapper07]

Thanks for the help!! I did some research and people usually do a closed loop system when running return on the bottom of a tank. I decided that I didn't want to risk it and purchased the bulkheads to do returns on the rear of the tank I wanted it super custom but in the end less headache is always better...

 

[grouper therapy]

Schwaggs;712443 wrote: I agree with the OP that Check Valves are doomed to fail eventually. I solved the siphon problem with my returns by running the return plumbing up the back of the tank's outside above the water level, then back down to the return in the back of my tank. I drilled and threaded a 1/4 fitting in the elbows at the highest level and screwed in a John Guest fitting with some 1/4 inch tubing to just below the water's surface. Works like a charm to break the siphon with limited back pressure (a few feet of pipe and 2 90 degree el's).

I did the same thing almost except I just ran a 1/4" line with the john guset valve up to the top of the tank and over instead of the pvc pipe.

 

[hogsnapper07]

Its going to look good in the end, I have the stand about 60% finished and will do some more to it this afternoon. The stand will be 48"x30"x42"tall frosted acrylic with color changing LED to light it up. It will also have a shadow box in the front that will have air bubbles running up the face of the stand and then there is a custom porthole we designed that will peek into my refugium/frag tank built into the stand. The tank will be 48"x30"x20" tall and havend decided whether to go with the new Ecotech Radions or just go with 2x 250w metal halides with LED supplements. I have a 48" LED fixture but think I will need a bit more light due to how deep the tank will be...

 

[bruce 1]

Schwaggs;712443 wrote: I agree with the OP that Check Valves are doomed to fail eventually. I solved the siphon problem with my returns by running the return plumbing up the back of the tank's outside above the water level, then back down to the return in the back of my tank. I drilled and threaded a 1/4 fitting in the elbows at the highest level and screwed in a John Guest fitting with some 1/4 inch tubing to just below the water's surface. Works like a charm to break the siphon with limited back pressure (a few feet of pipe and 2 90 degree el's).

Can you post a picture of your anti siphon?

 

[hogsnapper07]

BigJohn;712459 wrote: Are you doing moonlights?

Absolutely If I do halides I will just do little led moonlights but if I go with the built fixtures they will be included..

 

[tony_caliente]

I have a check valve and two 1/8 holes in the return pvc slightly below the water line. If the holes are kept clean, they should (and my do) break the syphon. I would also build or buy a sump that could take on a good amount of water. I am sure there are other solutions, those are just mine. I also use a float switch inside my display tank to shut off the pump in the even the overflow syphon breaks. While this has nver happended to me in 30 years, there is alway a first time (and SW wreaks havoc on hardwoods).