You should stop dosing until you get your test kit. The reason people have told you that you shouldn't need it with weekly water changes is that, when you mix new salt water it is balanced to have the correct calcium levels. This means every time you do a water change you are adding the needed calcium to your tank. The reason to dose is if your tank has enough calcium consuming organisms in it that the level is dropping below 400 between water changes. This usually takes quite a large stock of stony corals or clams to become a problem. Depending on how long you have been dosing, your calcium level could very well be at dangerously high levels. Every time you do a water change and dose you are adding more to the system, and without enough animals taking it out it will build up. When you get your test kit, test your water right after a water change and record the level. Wait a week without dosing, and test again. This will tell you how much per week your calcium level is dropping. Repeat this procedure for a few water changes so you can get a good sense of what your calcium is doing. If your calcium is never below 400 for the pre-water change test, you will not need to dose anything. If it is below 400 start by dosing one drop calcium in the middle of the time between water changes. Give it a couple of weeks again doing the pre and post water change tests to balance out and give you some good readings. If it is still low dose a second drop each week between water changes. I know it may seem to be a slow process that will take weeks for you to feel good about your calcium level, but remember everything must happen slow in a reef. Coral responds best to changes in very small and slow amounts.