Aquarium Test Tube Holder

thingiverse

Tired of carefully balancing the test tubes while testing water parameters in my fish tanks, I designed this test tube holder with a slit in the back to slide a piece of paper or index card for a white backdrop to see the colors clearly. I recommend printing in grey, white, or black so as not contrast against the testing liquids. Holds 6 test tubes with lids on. Doesn't need supports, just print the bottom right side up, and the top upside down, then apply a bit of super glue to the slots on the sides.