Herbie - I’m so lost!

[Picesduh]

Getting ready to order a 130 G peninsula and right now the overflow plan is (2) 1 inch drains and (1) 3/4 inch return.

I’m going to split the return so that 1 comes out of the over flow with loc line and a 2nd return outlet come over the top of tank on the side opposite the overflow side. This second return is a maybe because the pvc going up and over the tank will not be ideal aesthetically - But I will have flow on the far side which will “push” the water towards th overflow. Seems like a good thing...

Any way the question I have is how much GPH will the 1 inch overflow handle? I’ve been reading dozens of posts and articles and there seems to be a vast difference ranging from 360 GpH to 1500 GPH. The larger number is usually when the drain is a “full siphon” but what does that mean? I thought an overflow is gravity fed so it would be the lower number. How do I get the drain to go a full siphon?

I have not purchased the return pump so I can get a overrated one and tune it down if need be. I’m looking to have a 5x turnover but that’s because I saw it on a poll, I don’t know what’s best but that looks like a popular turnover rate.

 

[sbash]

A 1" pipe under a full siphon will pull over 2800 gph with a 6 foot drop... way more than you need...

So, what we do, assuming herbie, is put a valve on the overflow lines. Put a valve on both of your overflow lines, and pick which one you want to be the siphon. Make sure the siphon line's start is fully submerged.

When you fire up your pump, the siphon won't establish because you are not going to be pumping in 2800 GPH, so you close the valve on that pipe until the siphon establishes. The second overflow line then picks up the slack, ideally you build your overflow fittings for the second one to set the water level in the overflow box.

 

[Idoc]

I have a hetbie overflow design. I wanted to test my system in case of total blockage of my main siphon drain line to make sure my system could handle the flow to the sump if a disaster would ever happen...or if my DC pump would ever default to the highest return rate. I use a Varios6 DC return pump on a 75g tank. My 1" emergency drain line was able to handle 100% return pump flow without any display tank overflow! The Varios6 pump is overkill for my system, so that should work well for your system.

 

[Picesduh]

A 1" pipe under a full siphon will pull over 2800 gph with a 6 foot drop... way more than you need...

So, what we do, assuming herbie, is put a valve on the overflow lines. Put a valve on both of your overflow lines, and pick which one you want to be the siphon. Make sure the siphon line's start is fully submerged.

When you fire up your pump, the siphon won't establish because you are not going to be pumping in 2800 GPH, so you close the valve on that pipe until the siphon establishes. The second overflow line then picks up the slack, ideally you build your overflow fittings for the second one to set the water level in the overflow box.

Do I put a hole on the top of the pipe that’s submerged? I see that in a lot of the diagrams.

 

[lapin]

When the term full siphon is used it means the pipe has only water in it no air. When a pipe is totally underwater it pulls in only water. Perhaps this will help. Not sure why you will need am additional hole in the pipe.

 

[Picesduh]

Okay this is making sense now. I was just worried that the 1 inch occurred would only get 350 GPH but it looks like I misinterpreted that (I.e. full siphon is way more GPH). I don’t need to get 1.5 inch holes then in my tank. Thanks everyone!

 

[Dburr1014]

Use a gate valve to adjust the overflow pipe.