I got tired of having a half dozen loose bottles of test reagants, test tubes, color cards, etc all laying around under the tank. I went into the garage and built up a small "Test Rack" that can hold 8-12 bottles of reagant, 6 tubes, the cards, a pen, and my test log sheets (so I can see if my parameters are changing over time).
Here's what it looks like, along with a CAD drawing I made after I finished the project.
The one in the photos is not finished or sealed, but since I use a dropper to add the water to the tubes, it doesn't get wet. It's also a rough job, but since it spends the majority of its life out of sight, I don't mind.
If anyone is interested, I can send the CAD file w/ measurements. I might even consider starting a side gig building these to order for folks that would like them. (Test kits, counter top, rice cooker, and water bill not included