High Phosphates > 1,000 & High Nitrates 90ppm

[PoolDoc]

Hi Apple;

Neither phosphates nor nitrates consume chlorine by themselves. They can promote algae . . . but without algae, they have ZERO effect on chlorine.

These things do:
+ Algae
+ Sunlight, in the absence of CYA
+ Sunlight -- even WITH CYA -- in the presence of sodium bromide (anything from United Chemical, various algae treatments fm others)
+ Yellow OUT, Mustard Master, and other ammonia based algae treatments
+ Bromine (tabs)
+ Ammonia from biodegradation of CYA (in spring or after a major algae bloom)
+ Urine, sweat, lotion from swimmers

Other things consume some chlorine, like most algaecides. But it's not a huge effect.

HOWEVER, it sounds like you are inferring chlorine loss from the fact that you've turned up your SWCG and have no chlorine. But, since you don't really know whether your SWCG is working properly, you don't actually know if there is chlorine in the pool to lose.

ALSO, your test numbers tell me you are getting results from some sort of digital reader, probably of test strips. These are typically quite inaccurate (even dealer models) and WILDLY unreliable.

SO, do this:

#1 - Get a cheap OTO / phenol red kit at Walmart and 12 gallons of *plain* 6% chlorine bleach.
#2 - This evening, within 2 hours of sunset, turn off your SWCG, add 6 gallons of bleach, and then test the water 1 hour after.
#3 - The following morning, within 2 hours of sunRISE, test again. If your results are DARK yellow, you probably have an SWCG problem, not a chlorine problem.
#4 - Test again that evening. If the chlorine has dropped a lot during the day, from the AM reading, you have low stabilizer AND a bogus testing process.

There are some other possibilities, so report your results here. Also, consider buy an K2006 or K2006C -- these are pretty much the cheapest reliable kits with a DPD-FAS chlorine test component.

Ben