Hi, first of all, this web site is a goldmine! This is my first pool which came with the house I moved into last December and the advice I was getting from a certain unnamed store and the pool service company that opened it was a bit uneven, to put it diplomatically.
Yesterday afternoon (Tuesday) we got a torrential downpour (as bad as any hurricane I have been in) and when I got home, the shallow end had a brown cloud in it and the deep end skimmer was almost opaque with brown water which was oozing into the pool. I guess the drainage channel between the pool and the ground behind the house (which slopes to the pool deck) got overwhelmed and some muddy water washed into the shallow end. The deep end skimmer symptoms indicate water seeped into the piping system somewhere but that is a project for another day. I turned on the pump for several minutes to suck the deep end skimmer muddy water to waste and meant to add chlorine later that night but forgot to.
The next morning the pool had a uniform light haze to it. I thought it might have a slightly green hue to it so was concerned about algae. I poured in 2x96 oz. of 13.3% sodium hypochlorite (good for 5 ppm rise in 20K gal.) with the plan of buying some more that afternoon and shocking to 18-20 ppm (I have about 45 ppm CYA).
When I got back home (with 10 gallons of 12.2% sodium hypochlorite!) the water was a little clearer. I tested the water (Taylor) and got this result.
FC 6 ppm TC 6 ppm
TA 130 ppm (Carbonate Alkalinity is 113.4 ppm)
CYA 46 ppm
I did not test CH because I am having issues with getting a clear reading (topic for another post) but it is probably over 200 ppm. I have been getting some fine precipitate from time to time. I used the Taylor test kit saturation index and assumed CH was 225.
SI was .6
I calculated I needed 1.8 quarts of acid to get to pH 7.5. I added 1 quart to see what would happen. Retested after two hours and pH is about 7.8
I was expecting a significant difference between FC and TC due to organics combining with chlorine. The lack of significant combined chlorine (I recognize I might not be seeing a slight color change) tells me that the haze was not algae at all. It was probably the silt getting evenly spread and with the blue background and sun shining through some nearby trees, it took on a very slight green hue. When I removed some leaves on the bottom with the pool rake, I could see a faint cloud getting stirred up which could be settled silt, explaining why the haze was reduced.
Does that make sense?
And why would the pH go up so much. It was about 7.6 before the storm. Between the rain and the runoff, the pool gained 3 to 3.5 inches.
The major reason for this post is: What should I do now to make sure the pool is ready for the big Friday afternoon 16th birthday party? (I am posting this Wednesday night and the earliest I can do anything is Thursday morning.)
1) Play it safe and raise chlorine to 18 ppm and hope it lowers by Friday afternoon or just keep monitoring for a difference between FC and TC? (I would rather not have to dump sulfites in later.)
2) Put in something to clear the haze? I have two products:
HTH Natural Clarifier containing chitosan
HTH Flocculant containing aluminum chloride
3) Add some algaecide? Regal Algaecide 60, active ingredient has an amazingly long name (even for someone that had 6 college chemistry courses!) but I'm guessing dimethylimino is the active group.
I generally like the idea of minimizing any substance that will stay in the water and accumulate.
I also have HTH Enzyme Cleaner which does not seem to list the active ingredient but precautions are liberally sprinkled on the bottle.
I will be vacuuming the pool at some point but I'm not sure if I should coordinate that with using a clarifier or flocculant.
Any advice is appreciated.