This is kind of a weird thing. When I test my CYA with my Taylor K-2006 kit I get a high reading of 80. When I bring a sample to the local pool store they get a reading of 25. In the Taylor kit, I add solution until the dot on the bottom of the tube disappears. In the pool store test it has a black dot on a slide in a graduated cylinder which you can vary it's depth in the solution until it just disappears and read the CYA level from a scale on the slide.
The solution in the Taylor kit is the same as the pool store. Both kits mix solution and water for the test media. In the Taylor kit, I mix 7 ml of water and 7 ml of solution for 30 seconds. In the pool kit, I add water to one mark, and solution to the next up and work the slide 5 times.
They even gave me some new solution and their test tube. (for free) to take home and try. Results are still the same difference, even when using the new solution. What gives with the two different readings?
CYA: 25 or 80?
Copper: 0.4 I have a copper/silver ionization system for algae control which works great and allows me to keep lower chlorine levels and still have pristine water.