Raising DT waterline

[Aquavaj]

Right now the waterline is about 2" below the eurobrace and about 1" between waterline and bottom of canopy. That empty space just doesn't give it a clean seamless look that I want.

Can I cut a 1" strip of acrylic and silicone it to the inside of the overflow? This will partially block the weir cut outs and force the water to rise how ever high the strip is. Would this be safe?

 

[Rover88]

So long as you leave enough room to handle a 'surge' at the top of the tank and there is space for water to flow over it will be 'safe'....


If you block out too much of the weir or raise it too high over the distance in the overflow, you'll get a waterfall effect and you'll hear it.

 

[mcgyvr]

There are better adhesives to use than silicone.. Silicone does not stick well to acrylic..
Also note that silicone should be fully cured before you expose it to water and the inhabitants in the water to it.. That can take days to weeks depending on the kind and amount used..
Silicone is used for glass..not acrylic..

A smarter move might be to use plastic screws (nylon) or some other method to mechanically attach this "riser" piece to your overflow.. (maybe just screws right through the overflow teeth into the acrylic piece with threaded holes or use nylon nuts and through holes..)
That will also allow you to easily remove it as needed or whatever..

 

[der_wille_zur_macht]

I agree regarding mechanical fasteners vs silicone.

Maybe drill a few holes in the new weir and run zip ties through them.

 

[Darth_Tater]

If your drain(s) can handle more flow and your sump has room, increasing the flow into the display will also raise the water height. The more water moving through the same width overflow the higher the water level will be.

Doing this will lower the working water level in the pump chamber of the sump AND it will increase the amount of water that flows out of the display when the pumps turn off, so MAKE SURE you don't add more water than the sump can hold with the pumps off.

 

[der_wille_zur_macht]

That's true but you'd likely need A TON more flow to get a 1" difference in water level.

 

[2_zoa]

Raising the water level can be done doing that.

Though, let's start with what material the overflow is made of? Glass, acrylic
What type of drains do you have? Herbie, durso, beananimal
How much more water can your sump comfortably handle?

 

[Aquavaj]

Raising the water level can be done doing that.

Though, let's start with what material the overflow is made of? Glass, acrylic
What type of drains do you have? Herbie, durso, beananimal
How much more water can your sump comfortably handle?

Good questions.

-It's made of both. Inside has glass with an acrylic exterior.
-Herbie
-Not too sure. It's about half way right now with the pump on. I think it's a 3ft long sump but I need to measure to find out the water volume. Using the true tank dimensions and 1" water height yields about 5g. I think it'll be fine but might be close.

 

[2_zoa]

Do you have the Herbie setup to run a small amount of water through the emergency pipe currently? Or do you have it tuned really well with a constant water flow that you don't need to have it trickle through the emergency pipe? I have mine running with a trickle so it keeps things consistent even through nutrient swings.

Not totally sure how your setup is........However. It sound like you might be able to simply raise up the emergency drain pipe that extra (1") height that you need. It kinda sounds like the current overflow has the height in the teeth to accommodate your extra water and still keep your aquatic friends out?

 

[der_wille_zur_macht]

Tuning the water level in the main tank and tuning the water level inside the overflow box are separate, unrelated activities. Let's leave the Herbie out of the picture for now, since that's related to water level within the overflow.

Water level in the display tank is set by three factors:

1) The height of the weir on the overflow box. Above, there was discussion about adding a strip of acrylic to effectively raise the weir.

The second and third factor are basically related to the "thickness" of the sheet of water flowing over the weir:

2) The effective length of the weir: For a given flow rate, a smaller weir will have a "thicker" sheet of water flowing over it, so lengthening the weir drops the water level in the tank, while shortening it will raise it. Besides rebuilding the tank, the only effective way to shorten the weir would be to block some of it off.

3) The flow rate: a higher flow rate means a thicker sheet of water over the weir, which raises the water level.

The first point - weir height - is the easiest way to have direct control over water level, since it doesn't really disturb the rest of the system. Shortening the weir by blocking some of it off is a bad idea - shorter weirs are worse at surface skimming. Raising flow rate will raise the water level, as discussed above, but it will take A LOT more flow to raise it one inch. Here's how you can determine this: measure the thickness of the water flowing over the weir right now. I bet it's around 1/4" or maybe 1/2". Then divide by the height difference you want. So, if you have 1/4" of water flowing over right now, and you want a 1" raise in height, you would need to add four times your current flow rate. That's probably not possible without upgrading to a really huge return pump, re-doing your drain, and possibly re-doing your sump to handle the extra flow rate! Seems like a lot of work compared to zip-tieing a strip of acrylic at the exact level you want your water in the DT.

 

[2_zoa]

Tuning the water level in the main tank and tuning the water level inside the overflow box are separate, unrelated activities. Let's leave the Herbie out of the picture for now, since that's related to water level within the overflow.

Water level in the display tank is set by three factors:

1) The height of the weir on the overflow box. Above, there was discussion about adding a strip of acrylic to effectively raise the weir.

The second and third factor are basically related to the "thickness" of the sheet of water flowing over the weir:

2) The effective length of the weir: For a given flow rate, a smaller weir will have a "thicker" sheet of water flowing over it, so lengthening the weir drops the water level in the tank, while shortening it will raise it. Besides rebuilding the tank, the only effective way to shorten the weir would be to block some of it off.

3) The flow rate: a higher flow rate means a thicker sheet of water over the weir, which raises the water level.

The first point - weir height - is the easiest way to have direct control over water level, since it doesn't really disturb the rest of the system. Shortening the weir by blocking some of it off is a bad idea - shorter weirs are worse at surface skimming. Raising flow rate will raise the water level, as discussed above, but it will take A LOT more flow to raise it one inch. Here's how you can determine this: measure the thickness of the water flowing over the weir right now. I bet it's around 1/4" or maybe 1/2". Then divide by the height difference you want. So, if you have 1/4" of water flowing over right now, and you want a 1" raise in height, you would need to add four times your current flow rate. That's probably not possible without upgrading to a really huge return pump, re-doing your drain, and possibly re-doing your sump to handle the extra flow rate! Seems like a lot of work compared to zip-tieing a strip of acrylic at the exact level you want your water in the DT.

I'll partly agree with you. Yes as I stated... one would loose surface skimming. However, your example would make for a lot of noise as the water falls down into the overflow given the extra height.
Which.......makes my brain wonder.....
How is it even possible to have such a low water level in the display given an overflow is being used? DIY maybe? Aftermarket installed to low?
Glass plus acrylic makes me wonder about custom built tank?

Second, a "œthicker" wall of water going over the weir will skim like crap as you mentioned. I agree.

Third. A zip tied piece of whatever, will not be a water proof solution. So it will indeed affect the rest of the system because it will allow excess backflow into the sump. We are both thinking single point solution.

Now, If raising the weir is the solution. Then a piece of glass siliconed from the inside will be the best bet. However, I would still raise the emergency pipe to keep noise to a minimum.
My overflow makes noise if I let water fall more than 3/4" ish. I get that loud tricking noise. Drives me nuts while the wife says it's soothing.


Edit; I'm now interested in the returns. How are they setup to work with the water level an inch below the desired water level? Those outputs will also need to be raised. To keep backflow to a minimum.

 

[der_wille_zur_macht]

However, your example would make for a lot of noise as the water falls down into the overflow given the extra height

For the record - I never claimed that you couldn't, or shouldn't, alter the drain configuration to tune the water level in the overflow. I was just pointing out that it's a separate activity from tuning the water level in the display tank.

We can go back and forth on how the weir should be altered. Silicone doesn't adhere well to acrylic, if the overflow is acrylic then using silicone may not turn out well. Plus, you'd have to at least partially drain the tank and allow several days for curing. Mechanical methods (screws, zip ties) may not result in a watertight seal but at least they won't pop apart several weeks later like silicone on acrylic can, and you can get in, make the change, and have the tank running again in minutes instead of hours or days.

In the end, I'd recommend the OP do some tests or dry runs practicing with materials outside the tank, then do whatever method they're the most comfortable with.

 

[2_zoa]

I’m not looking to go back and forth. Just trying to make sure the info is kept straight so the advice can be sound advice.

The op stated the overflow is glass with an acrylic piece on the outside. So this is not just as simple as silicone doesn’t stick to acrylic message. This case there is an option to use glass and silicone and be totally secure.

 

[Floowid]

I have raised the tank running level before by cutting a piece of acrylic 2" by the length of the overflow teeth. I placed it behind the teeth and drilled holes that matched the weir teeth. 6 holes total, 3 sets of 2, each one tooth apart. Then I attached this acrylic strip behind the teeth with 3 cable or zip ties. Leave the ties somewhat loose to adjust the tank to your desired operating level them zip them tight when you get there.