White gritty scale

[PoolDoc]

Using more CYA reagent doesn't affect the reading: you mix a 50:50 solution of reagent + pool water, wait 2 minutes or so, and then see if the solution is 'cloudy' enough to make the drop disappear.

If it's NOT cloudy enough . . . you have zero stabilizer.

It's very, very unusual to have well water that is (a) hard [contains calcium] and (b) contains iron. Once you get the K2006, you'll need to test BOTH your pool water and your fill water. Try this link for the K2006, shipped BY Amazon. Try it in the AM Tuesday and Wednesday. They may well have some then, and you'll get it faster from Amazon than from any of the other sellers on Amazon.