How much water to use for a general hydroponic pH testing kit?

I lost the test vial it came with and I don't know how much water to mix with the 3-5 drops of PH test indicator. It says to fill test vial about half way, than add 3-5 drops of PH test indicator. Then mix. I need to know how many tablespoons or something that is in half a vial

3-4ml.

Its not a very delicate procedure,put some water in the vial and add a couple drops,no need to make it super complicated.

Not very accurate either. Get a decent ph pen from ebay. I got a nice one for under $50.