plumbing help please

[moses reef]

hey guys so I'm trying to connect a 5 gal tank as a refugium display to my actual display tank but I'm having trouble getting the water in and out at the same levels. I have the same exact power head but one puts out slightly more water than the other and it's gonna cause and overflow in about and hour if I let it go. how do you do this? any advice is great, thank you.

 

[NS Mike D]

one direction needs to be the pump and the other needs to be siphon, but you have to go deep enough in both tanks so that the siphon won't break and wide enough that the pump flow doesn't exceed the siphon rate. it will be impossible to match the flow rates of two pumps. if you want two pumps, you'll need to hook both up to float switches with redundancies in case a float switch fails.

 

[moses reef]

one direction needs to be the pump and the other needs to be siphon, but you have to go deep enough in both tanks so that the siphon won't break and wide enough that the pump flow doesn't exceed the siphon rate. it will be impossible to match the flow rates of two pumps. if you want two pumps, you'll need to hook both up to float switches with redundancies in case a float switch fails.

Okay so i just need to put one of them under okay cool. Im just curious how the same thing doesn't happen with the siphon, how do you know what size pump you need to match the rate of water coming down. Sorry ive never set one up before.

 

[NS Mike D]

use some tubing with a larger diameter for the siphon. as the pump draws water from one tank to the other, gravity will cause the water to flow back through the tubing without a pump. due to laws of physics i cannot explain, the pump will always push water through a tube faster than water will flow back through a siphon tube of the same diameter. you either have to step down the flow of the pump or use a larger diameter tubing for the siphon. mathematicians can calculate this.

 

[moses reef]

use some tubing with a larger diameter for the siphon. as the pump draws water from one tank to the other, gravity will cause the water to flow back through the tubing without a pump. due to laws of physics i cannot explain, the pump will always push water through a tube than water will flow back through a siphon tuber of the same diameter. you either have to step down the flow of the pump or use a larger diameter tubing for the siphon. mathematicians can calculate this.

oh I see, okay cool thank you man!

 

[Skydvr]

You may want to raise one of those slightly and drill it for a gravity return (assuming the glass is not tempered and preferably with an emergency backup drain) as this will be the simplest and most reliable method. At this point, it would probably be simplest to do that with the refugium.

A lot of the other methods can be quite finicky and prone to failure, especially during a power outage. Also, the siphon method relies on head pressure from the end of the siphon being lower than the level of fluid being siphoned to work effectively. If there is not much of a difference in water levels, the flow will be quite slow.

I can't quite tell from the pictures as they are kind of dark and I do not have the ability to adjust brightness and contrast on this device, I can't tell if those are homemade into AIO tanks and if you are running filter media in the overflow chamber of the refugium. Unless you are just going to be growing macro algea for nutrient export, you may want to consider removing those as the life in the fuge will not be able to make its way back to the tank.


Actually, now that I think about it, if you were okay drilling both tanks and considered making the filtration chamber into a single compartment on the refugium, you could drill the tanks on the side against the wall within the chamber to connect the tanks with a large enough pipe (or hose to minimize the risk of cracking the glass if one of he tanks gets shifted slightly, or is not alligned well from the start. Be sure to use opaque hose to minimze algae growth). There are calculator you can use based on the flow rate you are looking for. The pressure head would be somewhere around half the diameter of the pipe. Be sure to oversize slightly to allow for reduced flow over time to minimize flooding risk. A union could be used to go directly between the sides of the tanks that are together, but that might be a little more fifficult to set up as the hole placement would need to be ecact.
You can pump from either tank, but the tank you are pumping to will need to have the pipe in a spot where the water level will be at the level of the pipe (I recommend placing the line higher so that the tank does not drain in a case of catestrophic failure).
I recommended making the back section of the refugium a single section so that you could keep both tanks where they are and pump the tank to the refugium,(through the hole for the return pump nozzle if the tank was being used stock). This would result in the refugium draining into the pump chamber of the main tank, which would cause a portion of the refugium return to be cycled back though.
This works on the principal of two containers connected by a pipe having their fluid levels equaling out to the same height, only the pump is continually pulling water from one tank to fill the other. Similar to a gravity drain, but with both tanks on the same level.

You could accomplish the same thing with a pipe over the top of both tanks, but you would need to run a lift pump to draw air out of the pipe (similar to what people do for siphon drains for their sumps. The water will automatically level out between the two tanks as long as the pipe stays completely filled with water) to ensure air pockets do not build up and stop the flow. This is risky though because if air gets in the pipe (the pumps have a very small capacity and cannot overcome air being drawn in to the bottom of the pipe from low water level) or there is a prolonged outage, you may end up having power return and overflowing one of the tanks (possibly pumping the other dry depending on pump location).

 

[don_chuwish]

Good tips from Skydvr. Definitely go with an elevated refugium draining back to DT. It could look really cool too - almost like a drop-off tank.

 

[Engloid]

You also could drill and put pipe between then both. The problem with putting one up higher than the other is that if you will have to work in a siphon break on the pump line to keep it from siphoning the upper tank down to the lower one when power is out. It's possible though.

 

[Skydvr]

As long as the return is close to the surface of the water in the raised tank, it shouldn't be too much of an issue, but that is a good point that I neglected to mention. The lower tank does need the room to take up the volume that drains from the raised tank when the pumps shut down.

If the display pumps to the return pump chamber of the refugium and came in at a higher level, it would prevent, or at least minimize, the backsiphon when the pumps shuts off, but has the potential to be somewhat noisy as the outlet would need to be pretty close to the max water level.

 

[redfishbluefish]

You actually don't want one to be a siphon.....unless there is an overflow involved. If it's simply a siphon and a pump, you'd have to match flows....which is impossible. What you want is to have one tank lower then the other, with the low tank pumping back to the high tank. The high tank needs some type of overflow that can handle the pump volume coming from the low tank. The water in the high tank will simply flow into the overflow, which is connected to the low tank. I hope that is clear.

 

[Engloid]

You actually don't want one to be a siphon.....unless there is an overflow involved. If it's simply a siphon and a pump, you'd have to match flows....which is impossible. What you want is to have one tank lower then the other, with the low tank pumping back to the high tank. The high tank needs some type of overflow that can handle the pump volume coming from the low tank. The water in the high tank will simply flow into the overflow, which is connected to the low tank. I hope that is clear.

The siphon works just fine if you can keep air out of it. I used to run to 20 gallon tanks next to each other for a frag setup. I would pump from tank a into tank be and then siphon would return water from tank be to tank a. Essentially if you have a U pipe between two tanks, it will act to equalize the water level in the two tanks. Therefore it will work just fine if both of them are at the same elevation.

 

[redfishbluefish]

The siphon works just fine if you can keep air out of it. I used to run to 20 gallon tanks next to each other for a frag setup. I would pump from tank a into tank be and then siphon would return water from tank be to tank a. Essentially if you have a U pipe between two tanks, it will act to equalize the water level in the two tanks. Therefore it will work just fine if both of them are at the same elevation.

I am in agreement if side by side and the pump does not exceed the flow rate of the siphon.....but I still wouldn't do this.

It certainly will not work if one tank is below the other....it would have to be perfectly balanced, just like a two pump system, which is impossible without controls.

With the size of these tanks, I'm proposing a simple weir (overflow), on the upper tank with a pump in the lower tank that does not exceed the flow rate of the weir. Something like this:

 

[Engloid]

I am in agreement if side by side and the pump does not exceed the flow rate of the siphon.....but I still wouldn't do this.

It certainly will not work if one tank is below the other....it would have to be perfectly balanced, just like a two pump system, which is impossible without controls.

With the size of these tanks, I'm proposing a simple weir (overflow), on the upper tank with a pump in the lower tank that does not exceed the flow rate of the weir. Something like this:

I have done the two tanks, level, with one pump and siphon. It worked fine. That said, I think one above the other, depending on gravity (as you are suggesting) is a better idea, although a little more work. However, if you're going to drill tanks, you might as well drill them both, put a pipe between them and then pump from one to the other...with no need for any overflow at all. As with everything, there are pros and cons.