I have a very hard time with the CYA test. The only way I have any confidence in my test is if I mix a reference solution using the CYA 50ppm Standard Solution for comparison. I have a few questions:
1) Does CYA 50ppm Standard Solution sold by TFTTestkits.com expire? If yes, about how long should it last?
2) Can a Standard CYA Test Sample be mixed (CYA Standard + CYA Reagent) and kept for the season for quick reference/calibration?