I am building a hydroponic tower and was looking for a hydrometer that's compatible with my 50mm water hole. I couldn't find any that's slim & subtle enough so I decided to create one from scratch.

I used the hydrometer base & the 2 notched variants so it perfectly indicates the halfway & quarter way water depletion for my IKEA NYPON 32cm pot. If your tank is deeper or more shallow you can print more or less components so it fits perfectly for you.

Model is also quite lightweight, ~30g of filament for all base components. I personally printed it out of PETG since it's going to make contact with the water non-stop but I suppose you could print it out of anything.