I have been using TF100 for two years. Recently, my Calcium Hardness has crept up to 430ppm. I took a sample to two different Leslies and Warehouse Pool Supply stores (four stores total). All have given me values in the mid 200's.
Confused, I ordered fresh TF100 test chemicals, followed the procedure exactly, and continue to come up in the 430ppm range with TF100. I took another sample to one of the Leslies today, and they came up with 220ppm.
I don't know what to think. It is hard to refute the preponderance of results from the pool stores; however, I also know from this forum that pool stores are notoriously inaccurate!
Is there a way to home-make a "standard" solution to test against my TF100? Something like add Calcium Hardness increaser to distilled water in a known quantity, dissolve it, and then run it on TF100? If so, what ratio would I use.
Please help! Thanks,