OK. Unfortunately, this pool situation is not responding like normal pools do to the advice you have been given so far. I suspected that this high chlorine demand is due to stabilizer biodegradation to ammonia and/or urea like we are helping another member deal with in a different thread. (That is why I asked you to read the thread link I posted above.)

I consulted with Ben as to what advice to offer next. A few questions we need to know to help us solve this mystery:

1. Have you used any type of chlorine remover such as peroxide or thiosulfate in this pool?

2. You don't have massive amounts of floating algae, do you?

3. Have you ever used any products such as Yellow Out or Yellow Treat, etc. in this pool?

Can you timeline the pool from opening for us. What water was like when, and what the readings were. What you added when, etc. A timeline so we can see the progression more easily without having to keep scrolling back and forth through the entire thread. In addition, having it be more concise will make it easier to pinpoint the problem.

Also, can you tell us what your cya level was upon closing last fall and what it was upon opening this spring before you did anything to the water? Answer these questions and hopefully we can get this solved.