Herbie Overflow Question

hawkinsrgk · Apr 12, 2013

Hello Everybody

I am in the middle of plumbing my fish tank after a move and have a question. The tank is 180G (72 x 24 x 24) with 2 megaflow overflows. The standard 1 inch drain and .75 inch return. I have drilled the back of the tank to have 1 additional bulkhead that would be used as a Herbie overflow. The standard 1 inch drain would be the emergency drain and the .75 inch return would be the same. So the tank now has 6 total holes.

What are your thoughts on connecting the two 1 inch Herbie overflows after the gate valves together to a 1.5 inch PVC pipe that would then run to the sump? The sump would then have 1 1.5 inch drain instead of 2 1 inch drains. I have read that a 1.5 inch PVC pipe can handle more water flow than 2 1 inch pipes.

Thanks for the help
Randy

shovelrider · Apr 12, 2013

You lose the benefit of separate drains when you tie them together. Also, 2x1'' drains tied into a 1.5'' drain will only flow as fast as the 1'' drains. Do you have pics of the tank and center hole. How do you use the additional hole as a Herbie?

hawkinsrgk · Apr 13, 2013

hawkinsrgk · Apr 13, 2013

The bottom picture is from the left side of the tank and the middle picture is from the right side. I thought the top picture would help explain what I'm talking about.

What I have done so far has not been glued, so it would be easy to change at this point. I really don't like the look of how the plumbing looks now and wanted to change it where both Herbie overflows are T ed to 1.5 PVC.

I brought up the handling more flow part because I know a 1.5 inch PVC can handle more flow than 2 1 inch PVCs.

The main part I'm concerned about is how will the Herbie overflow on the right affect the one on the left or will it affect it at all?

The overflow inside the tank will handle the emergency drain and the return.

shovelrider · Apr 14, 2013

So you have a reef ready tank with 2 built in overflows that you have added 1 additional hole to from the back of each box? The original holes will all be emergency drains and the new holes will be primary drains? If this is the case, then as long as the new hole's gate valves are dialed in about the same you will be good. IMHO I would not tie the "gated" lines together, as these are your primary full siphon lines. These would benefit from draining separately. You would be able to tell what line gets a clog easier if they are separated (one side would go into emergency drain mode). It is possible to do it the way in question, but it would not be best practice.