I upped my usual water tests to 8 tests and have several reservoirs that required about two dozen tubes. The 5ml scale is accurate for the tests provided by API but their caps tend to leak so I went ahead and bought the regular rubber stoppers and they work great. Included is a link to stubs that are a good fit. Pack of 25 - CleverDelights Solid Rubber Stoppers - Size 000 - 13mm x 8mm - Length 21mm - Black Lab Stopper #000 https://www.amazon.com/dp/B01LZWPWFN/ref=cm_sw_r_cp_apa_i_UyudCbSB2ZX9Q
π¬ Aquarium Test Tube Holder: Hand-Made Rack with 6 Holes and Drying Poles
8 Review
FUNSWTM 7 in 1 Aquarium Test Strips: Accurate Water Testing for pH, Nitrite, Nitrate, Chlorine, GH & KH Levels
8 Review
Highly Efficient Seachem Purigen for Freshwater & Saltwater Filtration
9 Review
π Hanna Marine Alkalinity Checker HC - HI772: Accurate & Efficient dKH Measurement
9 Review
Efficient 2-In-1 Magnetic Fish Tank Cleaner With Non-Slip Design And Scratch-Free Blades
37 Review
π U-BCOO Aquarium Gravel Cleaner Fish Tank: Manual Siphon for Efficient Filter Gravel Cleaning and Water Change in Tanks
22 Review
Steam cleaner Deerma Deerma DEM-ZQ610 EU, white/red
68 Review
Jasonwell Magnetic Aquarium Fish Tank Glass Algae Cleaner - Floating Brush (L Size)
37 Review