Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Ditto the eye dropper/child medicine dispenser/syringe idea. I have all 3 in various volumes. The eye dropper with the squeeze bulb is the fastest, but the bulb wears out (lasts a long time, though). From eye dropper to turkey baster.
The syringe is really good for dosing several tanks. Take all you need in the syringe and dose each tank according to its need because the syringe is clearly labeled.
Child medicine measure or teaspoons (kitchen) are almost as bad as using the lid.
I use a Sharpie marker and mark the dosing on the bottles. Works great on the white bottles, and I have a silver Sharpie for dark bottles. Since I have several tanks I note a few doses on each bottle, so I can dose high or low levels.
The heavy duty sticky/post it with a rubber band will stay on really well, too.