75g Display System Design Plumbing Help Needed!

[ElZesto]

Hey Reef2Reef! I'm in the process of designing a new system using a Marineland 75g tank for display - drilled, H2Overflow for the Drain/Overflow, Eshopps R-100 sump, and a custom frag system that will be ~8g in the sump area (will be added later). Total system volume I expect will be 95-105g, although that's just a basic estimate. Here's the design images so far so you get the image:

Basic relevant flow info (please ask if I missed a piece of info):
H2Overflow with a 2 3/8OD hole, 1 1/2" ID Drain hole
Drains are 2X 1" herbie style (debatable)
Return is 1 (maybe 2 later) 3/4"
Return pump is Jebao MDP-2500, which I expect to run at ~60% for ~400gph return to be in the 4X-ish system volume return flow

I'm trying to figure out what my best option for the over flow/drain is. The H2overflow I have seems like a good design although I've seen a number of complaints about noise with it which I worry about, but, thinking through it I do like the varied/plentiful drain surface area as it really seems like this design would resist clogging much better than a traditional weir overflow since something would have to cover all 4 sides and the entire top to actually flood the display. The questions I have are:

1. Anyone used one of the H2Overflows? I've only seen neutral/negative things here about them, but its rare someone posts to say "yes it works as designed" so I'm taking the negative posts with a grain of salt.
2. Should I use an over flow box if I use the H2Overflow? It seems unnecessary with this drain style since the clog protection is via the drain/weirs, but idk really want some advice on this
2a. If I do an external over flow, the Eshopps LoPro External Overflow Box (800GPH) seems like a good fit, however id prefer to DIY it, so I'd probably just make a 8"L x 4"W x 6.25"H box attached to the side of the tank. Any reason that wouldn't work or isn't recommended?
3. If I do use the H2Overflow, is there any reason using flextype PVC to a gate valve is a bad idea? Are there any advantages to hard plumbing I should consider?

I appreciate any advice more experience people can share! I feel like these questions should be easy to google, but since this process is pretty high risk to screw up, I'd really like some advice directly from people who have been down this road before.

Thanks!

 

[lapin]

So you will have the main drain (cone) under water? and the h2o drain as your trickle drain? This will work as long as you have a valve on the main drain to regulate the water level. It will have the trickle noise.
Flex is as good as hard pvc. Maybe a bit easier to plumb.
Looks good so far

 

[ElZesto]

Yeah so if I do the overflow box, all the water will go through the H2o drain into the box, the H2o basically is a replacement for a traditional weir panel because I already have it. Then in the return the water level will be to the tall pipe like a herbie is. I'm basing this on this design:

There will be a gate valve on the shorter drainto adjust overflow water level:

The other option I've been thinking is just skipping the over flow box completely, because with the H2overflow I don't really see why its necessary. Instead using 1.75" ID tubing (either flex or hard idk yet) The basic design would be like this, although I'd likely still use a Union/90 to get it around the upper frame of the stand rather force that harsh angle on flex tubing:

Do you have any input on why one or the other design would be better? Noise? Flow control? Some type of flood risks I haven't considered?

 

[ElZesto]

So you will have the main drain (cone) under water? and the h2o drain as your trickle drain? This will work as long as you have a valve on the main drain to regulate the water level. It will have the trickle noise.
Flex is as good as hard pvc. Maybe a bit easier to plumb.
Looks good so far

Also just checked out your 500g tank. Woah dude. That thing is mind blowing.

 

[lapin]

I’m confused
If the H20 has only 1 pipe how will you make a herbie?

 

[RocketEngineer]

1) I would put the frag tank on the other end and drop the drains as close to vertical as possible. Ideally, use (2) 45 elbows instead of (2) 90s for the jog for better flow.
2) Look at larger overflow boxes. If you’re drilling the tank for the drain anyways, I would go bigger than the H2Overflow. JMO

 

[ElZesto]

I’m confused
If the H20 has only 1 pipe how will you make a herbie?

I’m saying either or. Like either doing an overflow box with a herbie, or just the h2o to a gate and that’s it.

 

[ElZesto]

1) I would put the frag tank on the other end and drop the drains as close to vertical as possible. Ideally, use (2) 45 elbows instead of (2) 90s for the jog for better flow.
2) Look at larger overflow boxes. If you’re drilling the tank for the drain anyways, I would go bigger than the H2Overflow. JMO

oh yes duh. The drain was oriented like that for a previous design with the frag tank where having the drain in the center was better, thanks for calling that out. Corrected.

I think overall since I'll need to drill the same hole in the tank regardless, I'm going to go get the basic things from the store today and just build the system in my garage like this except no frag tank set up:

I'll do testing to see how the noise/flow is with it in this orientation. I also want to try to over flow it to see If I can get it to fail, and how much stuff needs to clog the drain to do so. From thinking about it, I think the design of this H2overflow product seems much harder to clog than a traditional weir, but I've been wrong before (alot) so we'll do some garage science and report back! The final tank will have a reefPi setup on it for a controller, and we plan to put an optical sensor in the display tank to kill the return if it detects the water level too high for whatever reason which I think also makes this simpler design more reasonable.

Still open to any suggestions! Thank you @lapin and @RocketEngineer for your feedback! I appreciate the experienced voices chiming in!

 

[RocketEngineer]

If you only have one drain pipe, you never want a valve on it. Should a fish or snail end up in the pipe, you’re going to overflow. You only use a valve on a multi-pipe drain system.

 

[ElZesto]

If you only have one drain pipe, you never want a valve on it. Should a fish or snail end up in the pipe, you’re going to overflow. You only use a valve on a multi-pipe drain system.

Good to know! In that case then would the display water level be solely determined by the return flow?

 

[ElZesto]

ye olde garage science complete. Hole drilled, plumbing built, real life experiments were a great success. Conclusion: single 1.5” drain is just too dang noisy

The h2overflow product was easily silenced it seems with the use of the “restrictor” gasket things put in the hole of the drain, so I think that’s still a go, but we’ll see. Since it’s the only drain from display I’m hesitant to use any sort of “restrictor” on it, regardless, I have a theory about how to make it silent by playing with the water level.

Science pics:
Tank drilled (stressful, went well):

Stand with freshly installed yoga mat:

Some plumbing shots:

The conclusion: don’t reinvent the wheel, use an overflow box.

So on to a question:

1) I would put the frag tank on the other end and drop the drains as close to vertical as possible. Ideally, use (2) 45 elbows instead of (2) 90s for the jog for better flow.
2) Look at larger overflow boxes. If you’re drilling the tank for the drain anyways, I would go bigger than the H2Overflow. JMO

When you say larger than the h2overflow, do you mean using a weir with a larger surface area inside the tank? Or do you mean a larger external overflow box? I’m thinking the box dimensions will be 8”W x 4.5”D x 8”H all out of acrylic, and then use the bulkhead and some silicone on the overflow box panel/tank wall for extra support. Any suggestions or anything sound wrong with that plan?