First, I'm a pool school grad. Second, the relevant details are: I just purchased my new home two weeks ago and the seller had been out about a week before that. Basically the pool has had no bathers or chlorine additions for about three weeks. The pump is set to run four hours every day between 10a and 2p. Based on the pump gpm, est head and volume, the turnover is about 1.8x each day. I checked the filter which is fairly clean, the Nature2 cartridge could stand to be replaced, the automatic tablet feeder is empty with the feed rate set to "2" and the oxidier is operational with an injection rate of "4".
Since the day we moved-in, the water has been crystal clear. That is to say when I fill two glasses, one with pool water and another with filtered tap water you can't tell one from the other. Last week I took a sample to the store for an analysis. The results were FC 4, pH 7.2, Base Demand 2, TA 60, CH 400, TDS 1,400, CYA 101. The high CYA due to the tablet feeder apparently, so the only modification I made was to bring up the TA and pH with 6.7lbs of increaser.
I received my TF-100 yesterday and set out to take some real readings since my daughter is about to put a pillow over my face at night if I don't let her get in for the first time. I wanted to triple-check that the water is good-to-go first.
I first started with the FC DPD test and stopped at 20 drops (10ppm?) of reagent thinking I had done something wrong since the water was still a dark pink almost purple. I tried it again, but stopped at 30 drops. I then went to the simple K-1000 kit. That showed a reading of orange which obviously registers way off the scale and the pH read 7.3-7.4. I then went for a third DPD test and got to 40 drops (20ppm??) with no change in color and tried the K-1000 a second time with the same result. I went to different areas of the pool and made sure the sample was from over a foot down.
Given the results from the store, I'm at a loss. No one has touched, added chlorine or even used the pool in three weeks and it would appear my test is reading shock levels. The water has only a very slight chlorine odor and it tastes like normal pool water. I know the store tests are not totally reliable but my senses would certainly pick-up 20+ppm chlorine levels. Could I have bad kits? Thanks.