After my unfortunate iron treatment which has now resolved itself. In all likelyhood created by adding too much HEDP using Jack's Magic The Purple Stuff and/or a combination of too much Ascorbic Acid I was wondering whether or not a test kit for water was available that would tell me how much to use. Indeed there is such a kit available from Taylor Industries K-1584 , it is expensive at $114.50.
The question then is if one knew the iron ppm (another test kit) in ones pool and one knew the HEDP in ones water (this test kit) how many ounces of Jack's stuff would one need to to add say every week, two weeks, or a month. The test kit could be used to determine the concentration of HEDP in Jack's stuff.
I know, I know it is overkill but for those with Iron issues it would certainly be helpful and could more accurately determine the quantity of HEDP to put in the water to offset the iron coming out of solution. It might even save money in the long run by not overdoing it.
This idea possibly could work, if it can and that is a big if, how it will work I will leave to the chemistry gurus that visit this forum.