My 1st post and it's a little long, sorry. Our new pool was started just under 2 weeks ago now. It's a 15 KGal In-Ground, Plaster, Freeform.
When they came to start up the pool I was given a basic drop type test kit. The kit has no brand but tests for Total Chlorine, ph and Total Alkalinity. I used the kit for the 1st week as I started the task of balancing the water.
During a visit to the pool store to get more Chlorine later in the week I bought an AquaChek Digital Test Strip reader and some strips. It tests for Free Chlorine, ph and TA. Since these are the main tests I was concerned with right now and the startup guy had already tested my CH (250) and added stabalizer.
The Chlorine results where different of course but the ph was pretty similar. The BIG difference was the TA results. My drop kit was showing my TA rising as I was adding Baking Soda regularly. It was climbing from the initial reading of 20 and was up to 70. My target was between 100 and 120. The new test strip test showed me a TA of 140! Double the other result.
For a couple of days I tested with both kits. The Chlorine results where Ok (they where different tests, but matched what I expected), the ph was OK, they matched. The TA was always very different. My drop kit got up to 80 and then stopped. The strip test showed it climbing from 140 up to 165 as I continued to add BS per the startup guys instructions.
So I did some research on this board and others and the Taylor based reagent kits where pretty much recognized as the best. I ordered the TF-100 from here (AWSOME Service and rapid shipping by the way!).
When it arrived late this week I did a comparison test between the 3.
Un-branded drop kit (Water goes blue and has to be turned clear with counted drops) - 80
AquaChek Test Strip Reader - 190
TF-100 Kit - 110
Over the last couple of days the TF-100 result has stayed the same at 110, the other drop kit has stayed the same at 80 and the test strip has showed a gradual drop to 145. I haven't added any BS since mid week. My ph is varying little in the mid 7s. I have only added MA once this week when it climbed to 7.8. My CH is 210 and my CYA is 40. My Chlorine is up and down although I am not to concerned as the water is below 70, no bather load and I am waiting to start up my SWG in another couple of weeks. I add some every so often to keep it registering.
Should I ignore the Test Strip results and just use it for doing quick Chlorine and ph tests? Is this much variance between test kits normal? Why is my other drop kit stuck at 80? Can I rely on the TF-100, use it as my baseline test and consider my TA set for now?