So I will attempt to spit out all the info I can think of. I've owned this pool for over 10 years now, prior to that my Dad used to make me take care of his pool when I was a teenager.
Pool : Above Ground 21' x '41 vinyl, level bottom, approx 24,000 gal
I opened the pool very late in the season due to all the family issues we've been having lately. I was having trouble with the filter and got tied up in a couple of days, and poof, green pool. Nothing that's never happened before.
Filter is a Hayward EC50AC DE filter. Trying to keep a long story short after two weeks of fighting the filter "clogging" nearly immediately after turning it on, I finally broke it all down. I acid washed the finger cloth, I replaced a cracked bottom tube sheet. The filter is back up and working much better than it was but the pool is so green that it "clogs up" after about 15 to 20 min of run time and needs to be bumped.
Over the past two weeks I've used up 24lbs of powdered shock, 4lbs of Yellow out, 8 gal of liquid chlorine, just about a bucket full of Alkalinity up, 2 boxes of Borax.
Current test readings (AquaCheck Test Strips):
PH : 7.4 or 7.6 (hard to tell on this color chart)
Free Chlorine : >10 it's very very dark purple and the test only reads up to 10 ppm
Total Alk: 120
Stabilizer: 30-50 (test gives a range not an accurate number)
All of these readings are either "OK" or "IDEAL" or in the case of the chlorine "HIGH" (good!), and I've kept the pool at these readings since Wednesday (so it's been like this for 2 days).
I've been afraid to run the filter when it "clogs" up so I've been turning it off at night and anytime I'm not at home, so I know it's not running nearly as much as it should (I also do not have a timer, I'm going to buy one today).
So my questions:
In my prior experiences, I've NEVER had Algae "hang on" like this, ever. I've always been able to clear up a pool within a week.
I've "raked" the bottom with my leaf rake (as much as I can, cannot see the bottom), and I've brushed the sides down.
The only thing I can think of at this point is to take a water sample to the pool store and see what they say, but I'm always very skeptical of what they tell me.
Please help, is there some other tests I need to be running, what the heck could possibly be helping this algae live through this much chlorine??