Air pump to gang valve to aquarium

I am thinking of my aquarium rack setup. I have a 3 shelf rack. My plan is to put four tanks on the two lower racks (2 side by side on each rack). The air pump will on the top rack. In between the top and middle rack, I plan to put the 5 way gang valve. From the five way gang valve, they will have their own hoses to each tank. I will not be putting check valves anywhere and that is why I designed it with the air pump at the highest level.

So my question, is this a safe way in case the power goes out, is there any chance the top tanks will siphon water into the bottom tanks and over flow them? I would guess that as long as the gang valve is high enough above the middle shelf tank then there is no way the siphon would work.

 

Think you are right about that. It depends how high the valve is though. Water can "travel" even a little upwards by the capillar working in the airhose.

Another thing to think about is that there has to be sufficient pressure build up to serve all airstones and let them run.

What I mean is that with too little pressure
the top airstones will work but the air won't reach the lower ones. You might have to adjust the pressure to the top ones.

 

I would not suggest connecting all of the tanks to the same gang valve. If you do, every tank will need its own check valve. Connect the bottom row of tanks to one gang valve and the top row of tanks to another. I do not know where you live, but one gang valve I like is the one by Imaginatarium which has a check valve built in.

https://www.amazon.com/Imagitarium-Control-Check-Valve-Standard/dp/B06XJG67ZR

They are also available at Petco. The one shown has two valves, but you can also get a four valve model for a few dollars more.

You do not want any direct tubing connections between the top tanks and the bottom ones as the top tanks can syphon over.

If you get an air pump with two outlets, you can connect one outlet to each of the gang valves, Something like this one would be ideal.

https://www.amazon.com/Tetra-Whispe...pump+100&qid=1608381251&s=pet-supplies&sr=1-2

This one is supposed to be big enough for a 100 gallon tank, so it should be big enough for your application unless your tanks are really big, in which case, you probably should get more than one air pump.

 

DoubleDutch is right. I have had an air pump leak water within 15 or 20 minutes of unplugging the power from it (I didn't have a check valve, and the capillary action pulled the water up, and eventually over the lip of the tank. Happily, the pump was fine, and nothing else bad happened.)

I would recommend check valves. I know they are a pain to work with, and sometimes don't function our of the box, but they are worth the trouble to install.
My trick for finding out if they work, and which direction (as most cheap ones I buy don't have any labels indicating air flow direction) is to blow into each end and see which one is easier to blow through. That is the side that goes closest to the pump. If BOTH sides are hard to blow through, then the valve is broken. (If there is a way to FIX these "broken"valves, I'm all ears!)

The other option would be to get TWO pumps. One for the upper and one for the lower tanks...

 

Years ago I tried gang valves. I could never get them to work as well as they should. I gave up on them and now just put a control valve on each item that air is going to. In my case mostly sponge filters. I do highly recommend using a check valve. It is a very inexpensive item that can save a lot of headaches over time.

Both of the air pumps I have running right now have 2 outlets each. I have a check valve on each one of them. This in one of the "better safe than sorry" things I've learned over the years.