I read a post somewhere on TFP that if you do not have a test kit yet that there is a way to temporarily use a wal mart kit to test the chlorine levels. By that I mean there was a way to add water or something to come up with a higher ppm level. Does anyone know what I am talking about? If so could you please post that formula. Thanks.

You simply dilute the pool water by 2 (or more) and then multiply your result by the same number to get a VERY INACCURATE idea of your FC level (a 50% diltuion is not too bad.....any more than that is problematic)

It is in no way accurate enough to do an overnight FC loss test which will be required to finish your conversion.

During the early stages of a conversion the FC level falls very rapidly, so what you mostly need to do is wait for it to get down to 1 or lower, usually about an hour during the start of a conversion, and then add another 15 ppm of chlorine. The OTO test measures TC, which is FC + CC. The CC level is likely to be substantial, so there is another trick to getting the OTO test to work in this situation.

During the first several seconds of mixing, the color in the OTO tube will roughly indicate the FC level, then as just a little more time passes the color starts to change to show the TC level. What you are looking for is a clear or very pale yellow color, corresponding roughly to the 0, 0.5, or 1.0 colors indicated on the OTO comparator, during the first several seconds. If you see that, it is time to add more chlorine. If the FC level is higher, you will get a distinct yellow right from the moment the first drop from the dropper bottle hits the sample.

Later on in the conversion you will need to be able to measure high FC levels precisely, which will require using the FAS-DPD chlorine test. But just at first an OTO test is fine (with a little practice).

If anything I said doesn't make sense, feel free to ask questions.