Understanding Upside Down Aquariums with diagrams

This page is for helping you understand why expanding tanks and connecting them with large and small "upside down" fish tanks is completely safe when done correctly. The laws of physics are on your side when you expand a fish tank. Raising water from one water level to another creating multiple water levels is possible using a closed capsule sealed below the first water level. 
 Here's a RELAXING video of my albino oscar playing around in his tank connector, ENJOY!!!
Below is a diagram of a single tank on top of a regular, full body of water in the bottom tank, the top is empty.
There are two ways to remove air from the top tank, with a hole and a one way air valve, another is going from the inside with a tube and float to keep above water.
You can see below if you remove air from the top tank water level 2 will rise and water level 1 will go down. If you keep removing air water level 1 will reach the bottom rim of the top tank and it will "bubble" into the tank to compensate. Bubbling continuously as the air is being removed.
Going in from inside with the float, see video of how this works HERE.
There is no difference between the method you use, they both remove air from inside the top tank allowing the water level inside it to rise.
Here are two tanks side by side with the same or very close water levels.
Here is a connector added to the tanks with like water level.
Now imagine pouring in a bucket of water, the level will rise and just overflow from the tank. Thats why you remove air from the connector as you add water.
While you remove air from the top tank you will need to add water to one or both tanks, until the water is above the center gap, your water level in the bottom tanks will not be the same.
Once there's enough water in the top tank to complete the gap, you will now maintain the same water level in the bottom tanks.
You can keep removing air from the top tank and at the same time add water to either one of the bottom tanks. Since the tube will allow the water levels to breath just like a culvert in a ditch connecting two bodies of water to the same level.
Since there is water in the tube, if you raise or lower water levels in one of the tanks they will BOTH  fluctuate at the same time, like a culvert in a ditch the tube will maintain the bottom water level and keep them both the same, in the diagram below you can see water level is lowered in the right tank, water will flow from the left tank, through the tube and the water levels will stay the same.
Water will bubble in to compensate if you remove water from the bottom tank(s). It won't completely blow out as maybe thought at first.
 The left arrow shows that this water level is the SAME as the right tank while the connector is full (even though it doesn't really look like it).
You can remove water from either the left or right tank, then let it bubble in as you drain the tanks.
Use the tube and float to drain the tank also, see video below for how this works.
EUREKA!!! Hopefully you have a eureka moment while reading this page. I am trying my best to help you understand tank expansion safety!
Content copyright Ian Kvidt. All image's, information, instructions, guide's, diagrams, video's, and descriptions are intellectual property of it's respective owner, see disclaimer. Educational or recreational purposes only.