Hi this is a great forum and some really good reading, thanks for everyone's efforts and knowledge sharing.
Here's my situation and I apologize for not having accurate results posted (I'm at work right now), but I would love to understand what's going on in principle at a high level:
There is a ~13k gallon below ground pool at my parents house. I think it's concrete or something and the original color was a light green (which is annoying when trying to figure out how much algae I got now). It used to be a beautiful pool when i was a kid, but ever since I left for college my parents stopped having a professional pool cleanercome in. My dad has been chlorinating it with liquid chlorine and brushing it, on and off every 2 weeks for the last 10 years. No other maintenance in terms of chemicals, just chlorine and brushing. Occasionally washing the filters (cartidges). Looking at the pool now...it does not look inviting at all, it's a darker green than it should be and it's cloudy.
I've taken on the task of attacking this pool and getting it ready for the grand kids for this summer. I'm trying to read as much as possible, and getting advice from local pool store (Leslies) and here's what I've done so far. I went and bought powdered shock. Each bag of shock was supposed to be for a 15k pool. I used 2. I wasn't messing around. I wanted to destroy everything and anything . OK, so I guess that's my first mistake, after doing a bit of reading, I realize I should have balanced the pool beforehand, so I'm back pedaling a bit. After shocking, I ran my tests, PH was non existent as was Alkalinity results. So, I have a super chlorinated pool, which is very acidic and no alkalinity. I've read that PH and Alkalinity are tied to one another, so try and get alkalinity up first, and PH should follow. Pool store concurred after running my sample water, and recommended 15lbs of "Alkalinity Up", which I used. This helped bring the PH up a bit, but still well below 6.8.
I took the water sample back to the store and he they said I need more alkalinity up....I used another 10lb bag this morning. So hopefully it'll be much more balanced when i get back from work to test it again.
Here's the problem - The chlorine levels are THROUGH THE ROOF. I can't even tell you what the number is. I have a drop test, and if it turns a dark yellow, I know it's over the optimal levels. Well, when i put the drops in, it goes right past yellow into a dark pink. The pool store has confirmed that my chlorine levels are ridiculously high right now. It's been 3 days, I haven't added any chlorine...and it's not dropping at all.
Furthermore, the pool is still green. I brush it everyday. I've got some cloudiness/sediment at the bottom that I assume will filter out eventually over the next week or so (I did a thorough clean of the filters before starting the project). After a good brushing the pool gets quite cloudy, but will settle after a couple of hours and the water will be relatively clear....but the actual pool surface seems to have a algae still stuck to it. At these high levels of chlorine (I realize this can be bad for my pool equipment), I would assume the algae would be completely destroyed and get bleached out....but it's not? How long will this take? And why are my chlorine levels not dropping AT ALL? I don't have a CYA measurement yet, but if it was high, I'd be losing chlorine...so not sure why CYA would matter at this point (I understand it's dangerous for equipment, but in terms of killing algae which is my primary goal right now, it shouldn't hinder it)
I realize I have done things a bit backwards and I'm trying to get things balanced. But at this point I have large concentrate of chlorine int he pool.....and not a lot of results from an algae killing perspective, from what I can tell. Maybe I have some sort of chlorine resistant algae that has developed over the last 10 years? I noticed a leaf that had fallen on the surface yesterday is now bleached white.....but yet the darker green tint on my pool floor remains!!!! Any guidance would be appreciated....