Overflow overflowing help.

[USMA36]

I have a 240 gallon tank with an Exotic Marine Systems overflow. I believe the tank builder installed the overflow a fraction of an inch to high. As a result the water level in my tank is super close to the top especially with MP40s moving water around and some water trickles out each day. It runs down the back and sides of the tank. It’s only a few ML a day but it’s very frustrating. The water runs down gets between the black bracing and the glass and I end up with salt creep all along the bracing. Any suggestions on how I can fix this issue?

 

[BanjoBandito]

Do you have a gate valve on the return line(s)? Are you running a Herbie or a Bean setup?

 

[((FORDTECH))]

Pictures would help

 

[redfishbluefish]

Along the lines of @BanjoBandito , it sounds like your return pump is pumping more than your overflow can handle. If it's a controllable pump, crank it back a bit or if not, a valve on the return line can reduce flow rate.

The other issue could be stuff clogging up the drain line. After ten - twelve years, here's the inside of one of my 1 1/2" drain lines.

 

[((FORDTECH))]

Is it the teeth of the weirs are to high. Is it internal of the exterior box to high?

 

[BanjoBandito]

That's what I think, the siphon isn't equalized and your return is pumping too much for the overflow to handle.

 

[USMA36]

Unfortunately I’m at work. I don’t have pictures. Wont be home until Wednesday. The EMS overflow doesn’t have teeth. It uses open grooves. I am running a bean animal with 1.5” drains. My full siphon drain has a gate valve. I am running a Vectra L2 at 70%. I can try and slow it down and see if that helps. In my mind I didn’t think that would do anything. This is the overflow I have. https://exoticmarinesystems.com/product/32-overflow-w-1-5-drains/

 

[redfishbluefish]

You're pumping too much water! The Vectra L2 is rated at 3100gph while the overflow is rated at 1500gph. Assuming no head loss and linear graph, at 70% you're looking at 2170gph.

I wasn't familiar with this overflow, but looking it up, the draining water exits through the front slits, not up and over the top. If you're draining up and over the top, you're pumping too much.

Here's a video I found on that overflow:

 

[NowGlazeIT]

Unfortunately I’m at work. I don’t have pictures. Wont be home until Wednesday. The EMS overflow doesn’t have teeth. It uses open grooves. I am running a bean animal with 1.5” drains. My full siphon drain has a gate valve. I am running a Vectra L2 at 70%. I can try and slow it down and see if that helps. In my mind I didn’t think that would do anything. This is the overflow I have. https://exoticmarinesystems.com/product/32-overflow-w-1-5-drains/

I think you were right when you questioned the height of your emergency drain install. Water should cascade down your draines before ever rolling over the edge. Call the installer and tell them what’s going on.

 

[((FORDTECH))]

Unfortunately I’m at work. I don’t have pictures. Wont be home until Wednesday. The EMS overflow doesn’t have teeth. It uses open grooves. I am running a bean animal with 1.5” drains. My full siphon drain has a gate valve. I am running a Vectra L2 at 70%. I can try and slow it down and see if that helps. In my mind I didn’t think that would do anything. This is the overflow I have. https://exoticmarinesystems.com/product/32-overflow-w-1-5-drains/

I am not sure how handy you are but if this is truly an issue and I was having this issue if the tank is drilled to hi the only option I see is the cut the internal overflow box to make it shorter or possibly contacting Exotic marine to see if they could provide you with one that is shorter

 

[((FORDTECH))]

Otherwise as redfish said your pumping to much water thru it

 

[USMA36]

I can’t see too much water going through. There’s 2 1.5 inch holes it’s rated for 1500gph or more. My L2 at 70 is flowing through a manifold feeding a UV sterilizer and I have a ton of 90 elbows. My friction/head loss is probably sky high. When I get home Friday I’ll try reducing the flow. If it’s that easy that would be great. I just don’t see how slowing it down will lower the level in the tank. I would think the level is set by the height of the Internal box. Ext step will be to contact EMS.

 

[((FORDTECH))]

I can’t see too much water going through. There’s 2 1.5 inch holes it’s rated for 1500gph or more. My L2 at 70 is flowing through a manifold feeding a UV sterilizer and I have a ton of 90 elbows. My friction/head loss is probably sky high. When I get home Friday I’ll try reducing the flow. If it’s that easy that would be great. I just don’t see how slowing it down will lower the level in the tank. I would think the level is set by the height of the Internal box. Ext step will be to contact EMS.

As redfish posted the video of your overflow the water is supposed to go through the slits in the side not over the top if it’s going over the top it’s obviously too much water for the slits to handle therefore raising the level in the tank and going over the top

 

[Breadman03]

I can’t see too much water going through. There’s 2 1.5 inch holes it’s rated for 1500gph or more. My L2 at 70 is flowing through a manifold feeding a UV sterilizer and I have a ton of 90 elbows. My friction/head loss is probably sky high. When I get home Friday I’ll try reducing the flow. If it’s that easy that would be great. I just don’t see how slowing it down will lower the level in the tank. I would think the level is set by the height of the Internal box. Ext step will be to contact EMS.

Your flow into the box will be the width of the weir, plus however much water depth is needed to flow whatever GPH you're pumping. Basically, the width is fixed and the only way for more water to flow through is increased depth. Don't get me wrong, we're only measuring the changes in mm or so, but adjusting the flow *might* get you there if you're close. If you turn off your powerheads, how much room do you have between the water line and your rim? I've got like 2.5" on my rimless and can tune my pumps to make waves threateningly tall fairly easily, so wave tuning might also be a factor.

Here's a couple links, but not as good as the one I used a couple years ago. I ran the weir numbers a few years ago and compared my pump's electricity use to it's flow chart and found the results pretty close. Between low and high turnover, I was only looking at like 2mm difference with a smooth coast to coast overflow. With a smaller overflow, flow changes may have a bigger impact on tank level. I think flow adjustments will be worth an attempt.

Use a Rectangular Weir to Measure Water Flow Rate in an Open Channel

A rectangular weir is one type of sharp crested weir, and is of the options that can be used to meter flow rate in an open channel. The head over the weir is measured and can be used to calculate the water flow rate over the rectangular weir (and through the open channel). Two common types of...

www.brighthubengineering.com

Rectangular Weir Discharge Calculator and Equations

Rectangular weir design calculations, software

www.lmnoeng.com

 

[USMA36]

Slowing down the pump didn’t have any noticeable effect. Here are two videos. And https://youtube.com/shorts/I7WVDUYmQ-w?feature=share

 

[Breadman03]

Sooo, holes in glass don't relocate well. Given that your overflow is essentially at the top of the tank and that I don't fill up my coffee that close to the top, I might consider removing the overflow and enlarge the water groove downward a bit. I'm not sure if that's feasible, but it might let you move the tank water line a bit more. Maybe Exotic Marine could tune one up for your or someone with a hobby CNC router could open yours a little. I've got a Synergy Reef Shadow overflow that I'm keeping for my stock tank setup. If the fittings through the glass line up and it would fix your issue, I'd be willing to trade. Just send a PM and I can take a couple measurements. I'm near W-B and work in Stroudsburg, if that area is within your driving range.

Are you sure the builder didn't think you were going for a Zero Edge tank? lol

 

[USMA36]

Sooo, holes in glass don't relocate well. Given that your overflow is essentially at the top of the tank and that I don't fill up my coffee that close to the top, I might consider removing the overflow and enlarge the water groove downward a bit. I'm not sure if that's feasible, but it might let you move the tank water line a bit more. Maybe Exotic Marine could tune one up for your or someone with a hobby CNC router could open yours a little. I've got a Synergy Reef Shadow overflow that I'm keeping for my stock tank setup. If the fittings through the glass line up and it would fix your issue, I'd be willing to trade. Just send a PM and I can take a couple measurements. I'm near W-B and work in Stroudsburg, if that area is within your driving range.

Are you sure the builder didn't think you were going for a Zero Edge tank? lol

Thank you for the offer. I heard back from exotic marine. They think the box was installed about 1/2” too high. They can custom make a new internal box with higher bulkheads that would mount lower in my tank. That’s probably going to be my best bet. I don’t know anyone with a cnc machine or another way that could make the grooves lower in the water. I’m happy I at least have an answer now. I wish I would have investigated sooner. Tough to go back to the manufacturer months later with a complaint I should have caught much sooner. I’m still very happy with the tank though.