A couple questions about the DIY overflow

[TheWolfman]

I have one setup on my 220 and used it for my drip system for over a year without issues. It is still on my tank today and hasn’t lost prime. It’s now just added insurance if I walk away from my tank during refills. I didn’t use a check valve as I thought it was just away for air to find it’s way into the overflow. I also feel that the check valve sticking in the pipe would cause turbulence and raise the risk of air getting into the overflow via cavitation. By setting it up this way I had to assemble the overflow under water to prime it. But it does work well and keeps up with my tap.

 

[bobblehead27]

I have one setup on my 220 and used it for my drip system for over a year without issues. It is still on my tank today and hasn’t lost prime. It’s now just added insurance if I walk away from my tank during refills. I didn’t use a check valve as I thought it was just away for air to find it’s way into the overflow. I also feel that the check valve sticking in the pipe would cause turbulence and raise the risk of air getting into the overflow via cavitation. By setting it up this way I had to assemble the overflow under water to prime it. But it does work well and keeps up with my tap.

View attachment 1390101

I wish I had remembered to do the big PVC like that. Maybe I'll swap that part out....

But this is what I've got. How's it look, any design flaws you can see? For a 20gal I know I over did it with pipe thickness, but I hope that doesn't cause any issues... Is this primer and concrete necessary for such a low volume of water? Is this the right stuff? Sorry, have 0 experience with plumbing

 

[TheWolfman]

I wish I had remembered to do the big PVC like that. Maybe I'll swap that part out....

But this is what I've got. How's it look, any design flaws you can see? For a 20gal I know I over did it with pipe thickness, but I hope that doesn't cause any issues... Is this primer and concrete necessary for such a low volume of water? Is this the right stuff? Sorry, have 0 experience with plumbing

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View attachment 1398565

I would lower the T closer to the 90 on the bottom, if its too high it will loose prime. I would also recommend going with the larger pvc to make the overflow box. I believe that it’s more reliable than the way you have it set up currently. As far as the glue goes that is the correct stuff, and it is required. If you don’t glue the pvc your going to loose prime and have a flood on your hands. I would assemble it dry first and test it outside. Once your confident that it’s working properly then glue everything up. Hope that helps, just keep in mind lots of people myself included wouldn’t recommend using overflow boxes and would instead drill the tank if you planning on running a sump. What are your plans for this overflow?