Reddit reviews 13x100mm Glass Test Tubes with Screw Caps and Cardboard Rack, 3.3 Boro, Flat Bottom, 7ml Vol, Karter Scientific 227O8 (Pack of 25)
We found 2 Reddit comments about 13x100mm Glass Test Tubes with Screw Caps and Cardboard Rack, 3.3 Boro, Flat Bottom, 7ml Vol, Karter Scientific 227O8 (Pack of 25). Here are the top ones, ranked by their Reddit score.
13x100 Screw Tubes made of Borosilicate GlassFlat BottomBlack Phenolic Screw Caps with Teflon Liner25-Place Cardboard RackVolume: 7ml
I got these. I use a 5ml syringe (like what you use to dose kids liquid meds) to measure out water from my tanks into those test tubes.
My only tip would be, the lids can be a bit fussy, make sure the top inside liner is flush to the top (poke it down if it isn't) and they'll screw on better.
I use these:
https://www.amazon.com/gp/product/B01L86ZRDO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1