simplest way of connecting two tanks

maleks.reef · Feb 27, 2022

Reefer Reboot said:
If you are interested in making something that does not require drilling or hard plumbing the tanks together, here is a simple concept that will accomplish an interconnection.

With the tank tops at the same level, use a basic powerhead to induce (not force) flow through the left "U-tube". Leave a gap between the powerhead outlet and the "U-tube". The right "U-tube" will equalize the tank levels. With an airline, connect the low pressure venturi port of the powerhead to the high point of both "U-tubes" to remove any air to keep syphon.
This is just the basic concept.

Thank you so much for taking the time to do this. I get the point of the pump and the 2 U tubes, however, I do not fully understand the function of the airline. Also, is this design fail-proof? Ie. if any pump in the DT or frag tank fail, would anything flood?

Greg Gdowski · Feb 27, 2022

maleks.reef said:
Thank you so much for taking the time to do this. I get the point of the pump and the 2 U tubes, however, I do not fully understand the function of the airline. Also, is this design fail-proof? Ie. if any pump in the DT or frag tank fail, would anything flood?

I thought you didn't want the frag tank to be at the same height or higher than the other tank?

Reefer Reboot · Feb 27, 2022

maleks.reef said:
Thank you so much for taking the time to do this. I get the point of the pump and the 2 U tubes, however, I do not fully understand the function of the airline. Also, is this design fail-proof? Ie. if any pump in the DT or frag tank fail, would anything flood?

The airline is there to draw out any air that accumulates in the top of the U-tubes which could break the syphon. Granted, it will be inducing the air back up the left tube but the powerhead should turn it into micro bubbles which will eventually follow the flow out the other side. For this reason it would be best to keep the ends of the tubes as shallow as possible without breaking the syphon. Is it "fail proof"? Is anything truely "fail proof"? I hate to use that term because there is always some extreme situation that could defeat anything. Again, this was just the basic concept. For actual implementation it would be better to mount like this.

With the powerhead mounted as shallow as possible (without drawing air into the pump), it would stop the induced flow once the water level of the frag tank dropped. If the powerhead were to fail, the water levels of both tanks would equalize. If the DT pump would fail. the DT water level would most likely lower some as the AIO filled up. Worst case scenario there (that I can see) is that the frag tank would equalize with it until the syphons are broken and/or the powerhead draws air.
One thing to point out, you will still probably need some kind of additional flow within the frag tank itself depending on the corals you are growing.

Greg Gdowski · Feb 27, 2022

Reefer Reboot said:
The airline is there to draw out any air that accumulates in the top of the U-tubes which could break the syphon. Granted, it will be inducing the air back up the left tube but the powerhead should turn it into micro bubbles which will eventually follow the flow out the other side. For this reason it would be best to keep the ends of the tubes as shallow as possible without breaking the syphon. Is it "fail proof"? Is anything truely "fail proof"? I hate to use that term because there is always some extreme situation that could defeat anything. Again, this was just the basic concept. For actual implementation it would be better to mount like this.

With the powerhead mounted as shallow as possible (without drawing air into the pump), it would stop the induced flow once the water level of the frag tank dropped. If the powerhead were to fail, the water levels of both tanks would equalize. If the DT pump would fail. the DT water level would most likely lower some as the AIO filled up. Worst case scenario there (that I can see) is that the frag tank would equalize with it until the syphons are broken and/or the powerhead draws air.
One thing to point out, you will still probably need some kind of additional flow within the frag tank itself depending on the corals you are growing.

The challenge is having two of these run in parallel. The key to this system working is that the 2nd tank (one with pump) is the same level or higher than the display tank. The original poster did not want the frag tank to be that high. You can lower the 2nd tank in this picture -- but I don't think two can be run in parallel without risk.

Reefer Reboot · Feb 27, 2022

First off, I completely agree with you that the best course of action would be to incorporate a sump!!

But the parameters that the OP is trying to work with was stated as, "So what is the simplest way of connecting the two together? (Im not interesting in hard plumbing or drilling either tank)"(post #1). That alone creates a hugh limit on possibilities.
Also stated,
"Ideally, i would get another white stand so that it is not so low,..."(post #1)
"Well having the frag tank higher than the display is not really an option because the stand would be very tall and absurd, unfortunately."(post #9)
Maybe I missed it somewhere but I did not see where the frag tank couldn't be set up as "With the tank tops at the same level..."(post #40)
I thought the OP was on the right track in post #36, although this part is a concern, "I have more water in the tank than the suggested level , also i have a HOB skimmer that dumps even more water into the tank when everything is off, so the water does go over #1 actually." Why is this happening? I did make the incorrect assumption in post #43 that the water level would drop. But OP also states "I would say the tank would be able to accommodate for 6-10 additional litres with everything off." If set up properly, the syphons should break before that point.
I know, I know,;Sorry details,details details.
But let's get back to the best idea, incorporating a sump.....

maleks.reef · Feb 27, 2022

Reefer Reboot said:
First off, I completely agree with you that the best course of action would be to incorporate a sump!!
But the parameters that the OP is trying to work with was stated as, "So what is the simplest way of connecting the two together? (Im not interesting in hard plumbing or drilling either tank)"(post #1). That alone creates a hugh limit on possibilities.
Also stated,
"Ideally, i would get another white stand so that it is not so low,..."(post #1)
"Well having the frag tank higher than the display is not really an option because the stand would be very tall and absurd, unfortunately."(post #9)
Maybe I missed it somewhere but I did not see where the frag tank couldn't be set up as "With the tank tops at the same level..."(post #40)
I thought the OP was on the right track in post #36, although this part is a concern, "I have more water in the tank than the suggested level , also i have a HOB skimmer that dumps even more water into the tank when everything is off, so the water does go over #1 actually." Why is this happening? I did make the incorrect assumption in post #43 that the water level would drop. But OP also states "I would say the tank would be able to accommodate for 6-10 additional litres with everything off." If set up properly, the syphons should break before that point.
I know, I know,;Sorry details,details details.
But let's get back to the best idea, incorporating a sump.....

As much as i would like a sump, it is simply not a viable option for me currently. That being said, the idea you suggested is brilliant and it should work. I do not mind having the 2 tanks on the same level so that shouldn't be a problem. Only problem is to find the required parts and a pump that would do this job perfectly. I have never plumbed anything in my life other than my basic RODI unit lol so I do not know where to start on these tubes and other parts. If you could give me a list of the names of all the parts required to do this, i would greatly appreciate it. Once again, thank you!

Greg Gdowski · Feb 27, 2022

Reefer Reboot said:
First off, I completely agree with you that the best course of action would be to incorporate a sump!!
But the parameters that the OP is trying to work with was stated as, "So what is the simplest way of connecting the two together? (Im not interesting in hard plumbing or drilling either tank)"(post #1). That alone creates a hugh limit on possibilities.
Also stated,
"Ideally, i would get another white stand so that it is not so low,..."(post #1)
"Well having the frag tank higher than the display is not really an option because the stand would be very tall and absurd, unfortunately."(post #9)
Maybe I missed it somewhere but I did not see where the frag tank couldn't be set up as "With the tank tops at the same level..."(post #40)
I thought the OP was on the right track in post #36, although this part is a concern, "I have more water in the tank than the suggested level , also i have a HOB skimmer that dumps even more water into the tank when everything is off, so the water does go over #1 actually." Why is this happening? I did make the incorrect assumption in post #43 that the water level would drop. But OP also states "I would say the tank would be able to accommodate for 6-10 additional litres with everything off." If set up properly, the syphons should break before that point.
I know, I know,;Sorry details,details details.
But let's get back to the best idea, incorporating a sump.....

maleks.reef said:
As much as i would like a sump, it is simply not a viable option for me currently. That being said, the idea you suggested is brilliant and it should work. I do not mind having the 2 tanks on the same level so that shouldn't be a problem. Only problem is to find the required parts and a pump that would do this job perfectly. I have never plumbed anything in my life other than my basic RODI unit lol so I do not know where to start on these tubes and other parts. If you could give me a list of the names of all the parts required to do this, i would greatly appreciate it. Once again, thank you!

The one thing to worry about this setup is if the siphon breaks on the return limb. The pump will continue to suck water into the frag tank until the "other" sump is empty. So your frag tank will have to be able to accommodate the volume of the sump (at least until the pump in the sump starts taking in air). The same thing can happen if the pump is sucking in water at a higher rate than is being returned by the siphon/return (ie partial clog). To partially alleviate this risk, I usually put a level sensor on the tank and turn off the pump if the water is too high.

Spieg · Feb 27, 2022

This is one of the reasons I don't have AIO tanks, you are pretty limited in what you can do. To add a sump in a reliable/safe way, you pretty much need to remove the bafles for the AIO partition and drill the tank for a conventional overflow. Not worth the effort IMO.

Greg Gdowski · Feb 27, 2022

Spieg said:
This is one of the reasons I don't have AIO tanks, you are pretty limited in what you can do. To add a sump in a reliable/safe way, you pretty much need to remove the bafles for the AIO partition and drill the tank for a conventional overflow. Not worth the effort IMO.

I agree, but I wrote a lot here because I'd like a solution for the same reason. Every time I think about this, I come back to a siphon to the frag tank with a controlled pump back to the display tank. The pump would slow down if the water is getting too low and speed up if it was getting too high. That way the pump output would change its rate based on the state of the siphon. Still makes me nervous. Someday I may try it, but that will certainly be in the basement.

Reefer Reboot · Feb 28, 2022

maleks.reef said:
As much as i would like a sump, it is simply not a viable option for me currently. That being said, the idea you suggested is brilliant and it should work. I do not mind having the 2 tanks on the same level so that shouldn't be a problem. Only problem is to find the required parts and a pump that would do this job perfectly. I have never plumbed anything in my life other than my basic RODI unit lol so I do not know where to start on these tubes and other parts. If you could give me a list of the names of all the parts required to do this, i would greatly appreciate it. Once again, thank you!

The tube parts are just PVC tubes and fittings. 2 tee fittings and 6 elbow fittings and then a stick of tube that you will need to cut to the proper lengths. I would guestimate using either 3/4" or 1" diameter tubing. You will need 2 reducing bushings for the top of the tees in which to install 2 air line push fittings (non metalic). Airline and an airline tee. Then a powerhead pump that has a venturi low pressure port (which is usually used to suck in air).
Hopefully the terminology and names are similar for you in the United Arab Emirates. Is there anyone with plumbing experience you can talk to for help if need be?

maleks.reef · Feb 28, 2022

Reefer Reboot said:
The tube parts are just PVC tubes and fittings. 2 tee fittings and 6 elbow fittings and then a stick of tube that you will need to cut to the proper lengths. I would guestimate using either 3/4" or 1" diameter tubing. You will need 2 reducing bushings for the top of the tees in which to install 2 air line push fittings (non metalic). Airline and an airline tee. Then a powerhead pump that has a venturi low pressure port (which is usually used to suck in air).
Hopefully the terminology and names are similar for you in the United Arab Emirates. Is there anyone with plumbing experience you can talk to for help if need be?

Yes i am sure ill able to find all of those parts. Thank you so much!

One last question, would the airline tubing that's preventing the siphon from breaking lead to microbubbles in my DT since the pump would be pushing air into the dT?