Today I picked up a pool that was firing another pool company in the area. The pool was opened back in May, but hadn't been touched since until a few days ago.
When I arrived this morning, the pool didn't look as bad as I thought it would. I could see the bottom in the shallow end, and the pool had a cloudy blue color. I tested the water with a test strip (I know, not the best) and saw no FC, no TC, very low pH, low TA, low CH, low CYA. I started hitting the pool with chemicals. I put in 16lb of trichlor shock. I tested between shocks, and I kept finding that by the time the water came out the return jets, the FC was zero. I added about 25lb of Cal-Hypo, and again, the FC didn't budge. I did start to see Total Chlorine readings after both additions, but no FC. I was able to get a very low reading a few times right at the return jet, but a few feet beyond it was zero again. I started adding 12% liquid chlorine. I put in over 30 gallons, and I still can't get an FC reading above zero. These additions of chlorine weren't all at once, I made 3 visits to this pool.
When I added the granular chlorines through the skimmers, they bubbled vigorously, and I could see the yellow chlorine gas bubbling out. When I added the liquid chlorine, I could see a fine fizzing as the chlorine was dispursed by the return jet.
I know it wasn't the test strips going bad, because they worked fine on every other pool I worked on today, and I also tried a brand new pack. I even poured liquid chlorine on one to make sure they were reading. The only other chemicals I added to the pool today were pH increaser and Polyquat.
I'm assuming that the pool was cloudy blue instead of blackish green because of the polyquat killing the algae.
So my initial thoughts were ammonia. I figured I should be able to add enough chlorine, and eventually the ammonia is used up, and the FC will come up. After using more chlorine than I use in a month on all my other pools combined on just this pool in a single afternoon, I'm questioning that idea.
Is there anything else that could be doing this? This is the first time I've seen anything this bad. I've seen pools with ammonia, but usually after a few pounds of trichlor, they are back on track.