Hi, Thanks for all the information. Gave me some ideas and did some experimenting. From the Joy of Cooking, 1 teaspoon = 5 ml. It also said 60 drops = 1 ml. So I took 3 different size droppers...a tiny baby medicine dropper. a bottle with a dropper originally for fish medicine, and a turkey baster.
The baby dropper yielded 90 drops to a teaspoon, ie: 18 drops to an ml
Fish bottle was 60 drops to a teaspoon, ie: 12 drops to an ml,
Turkey baster was 12 drops, ie: would round up to be about 2 1/2 drops to an ml.
Using the baby dropper into some different used super mini cartridges with filler, it took between 6-8 drops to fill the cartridge. That is about 1/3 ml per cart.
The cart filler looks like the roll of filter material I use for my fish pond. As T-Bob noted, it can be had at a pet store. Also to note is since fish are super sensitive to many things, (for example, a regular household sponge material can kill fish), one can reasonably assume the aquarium filter material is quite pure in it's qualities.
Syringes could probably also be had on veterinarnian or dog breeder supply websites because breeders & vets use them to administer medicine and to feed orphan newborn puppies.
I have purchased carts from 2 different supplies. One type was enclosed in what looks like a miniture thimble. The other came with a new tip. The former was full of e-liquid, produced alot of vapor, while the others often are dried out & not full. Natch the latter were considerably cheaper. Just ordered a 30 ml bottle of e-liquid from the Ebay seller to fix the 90 cheaper carts....nuttin' like a 'good' bargain, eh? LOL
Barbara