Need help fast

[Sumo1]

Helping a friend with her 16 x 32 liner pool, with salt water generator (not sure on gallons). Said her pool is green with algae, she hasn't turned on the generator yet. She had a pool store test her water. FC is 0, ALK is 117, PH is 7.9, CH is 39. The pool store sold her 3 gallons of muriatic acid to use over the next couple of days and sold her a quart of copper algaecide.

I'm going to see the pool after work. I told her to wait to put anything in pool, to turn on her salt water generator and to keep brushing the pool while running her sand filter. I will pick up a few gallons of bleach on the way to her house. What else should I do? Any suggestions? 3 gallons of muriatic was more than I used all of last year.

Thanks in advance.
Hal

[JohnT]

Don't use the algaecide. Get more than a few gallons of bleach. If she doesn't have access to a test kit, she'll probably be in for a long road. Leave the SWCG off until things are cleared up. Maintain chlorine at 15ppm. This will probably require testing and more chlorine every 4 hours or so for the first day.

[mbar]

You won't need all of that muriatic acid. Maybe a cup or two at most. You just want to bring the ph down to 7.5, the alkalinity if fine, and the calcium is fine for a vinyl liner pool. You will need a lot of bleach to keep the chlorine level at shock, which will be different according to how much cya is in the water. Ususally with a salt water generator they want the cya ato 60 or above, so I would make sure I get a cya reading fast, so you know how much chlorine to keep in there to clear up the algae. Do not turn on the salt genterator till the algae is cleared up - no use in running it if you have to be adding chlorine all the time anyway. Make sure you check the chlorine level at night and in the morning, this way you can see if the free chlorine is holding overnight. I really think a good test kit is the most important tool you can have when you have a pool. When you have a high chlorine level in the water, the ph test may be off, so worry more about having the chlorine in than anything else right now. Here is the best guess chart:

Use the info in this chart to help you figure out what levels of chlorine you need to maintain in your pool based on the amount of CYA (cyanuric acid, also called stabilizer) that you have in your pool. (FC = free chlorine)

Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

Let us know if you have any other questions

[Sumo1]

Thanks for the quick responses. She bought the pool middle of last summer and it looks like PB did a pretty nice job, but other than the cursory "Do this.. Don't do that.. Here's your manual..", he didn't explain things very well. Now she's a Poolforum student:D
When I got there she had added three 176oz jugs of 6% bleach. The pool is 19000gal with a Zodiac DuoCore cartridge/sand filter system and Polaris 65 cleaner. I tested the water with my Taylor K-2006 kit and found....
FC-14.6
CC-.8
pH-the color was brighter than the scale so definitely over 8.0
TA-120
CYA-0/not measurable

So, SWCG is turned off and system is running 24/7. Her owner's manual says 13.8lb CYA for 80ppm but I said put 5 or 6lb then we'll test again. I'll go by there and test the water by about 11AM. Not ideal test intervals, but I don't live there so it'll do. I put in about a quart of muriatic in hopes I can get a better reading tomorrow. The other jugs she thought were muriatic turned out to be 10% bleach. I added one of them before I left. Not perfect testing procedures but there is a lot of green algae and the added bleach should keep the FC from dropping too much 'til I can get back. I suggested she return the copper stuff. How'd I do? First time I've ever tried to apply what I've learned here with someone else's pool! Thanks everyone--
Hal

[aylad]

How'd I do? First time I've ever tried to apply what I've learned here with someone else's pool!

You did very well--you've obviously been doing your homework!! The only comment I have right now is to make sure you wait at least a week before retesting for CYA....it is VERY slow to dissolve, and if you retest or add too quickly, you could end up with a much higher level than you want.

Oh...also, if she still has green, make sure that she's brushing the pool at least once a day while running the pump 24/7.

Good job!

Janet

[Sumo1]

Well, got by there to test about 11:15 and here's what I found....
FC-8.6
Cc-.6
pH-still 8+ but not as vivid as last night
alk-~100

Not too much visual change in the pool color . I put in about a quart more muriatic and 2 more 1gal jugs of 10% pool store bleach and had to run. Will report back when I have more info. Should I keep trying with the muriatic or just wait until the pool clears? Thanks:)
Hal

[aylad]

Should I keep trying with the muriatic or just wait until the pool clears?
Hal.


I would fix one problem at a time...often trying to focus on too many things at once just compounds the situation. She's not going to swim in it until it's clear, so I would focus on clearing the pool first, then worry about the pH.

Janet

[Sumo1]

Well, a week's gone by and I haven't gone to her pool but she said things had cleared up and she put 3lb CYA in a stocking in the skimmer a week ago. Now my friend left to go north for her Mom's birthday so I went by to see and test the pool. I cleaned the filter and pump baskets- the pool looks great. The test was done about 8:45pm. I found
CL-2.5
CC-(forgot this one before I tossed the water sample:o )
pH-~7.0
Alk-70
CYA-~45

What should I do now? It's a 19K liner pool. Will the low alkalinity hurt anything, do you think? Thanks!
Hal

PS-I added 176oz of 6% bleach before I left.

[aylad]

Will the low alkalinity hurt anything, do you think? Thanks!
Hal

PS-I added 176oz of 6% bleach before I left.

Low alk shouldn't hurt anything, but she's probably going to have a hard time keeping her pH stable. I'd raise it just a tad, to around 100.

Janet

[Watermom]

I would also raise the ph a bit. 7.0 is a little low. Bump it up to 7.4-7.6 or at the very least, 7.2.

[Sumo1]

Since I do try to do my homework, and pH and alk often seem to go hand in hand, should I add baking soda for the alk then wait before trying to alter pH? Thanks
Hal