Had algae; did Green to Clean and 3 cycles of shock; now have pale green cloudy water

Hi,
We have had an Intex AG pool for the summer and about 3 weeks ago, we had an algae bloom. Our local Leslie pool place had us do Green-to-Clean and 3 cycles of shock and some Pool First Aid--did nothing. We then got a Game Sand Pro 50 filter and tried again with twice the dose of Green-to-Clean and shock. Our pool went from olive green to light minty green (which Leslie said was a good sign--algae's now dead). Then we found PoolSolutions and PoolForum and haven't added the Pool First Aid due to some of what we've read.

It's been 3 days since the last shock treatment and the pool is still cloudy light green. We tested the pool with a Taylor k2006 and found that most of the levels are in-range except chlorine.

FC (1.8mL sample diluted with tap water): ~3ppm x 5 = ~15ppm
TC : ~3ppm x 5 = ~15ppm
CC: ~0
pH: 7.6
TA: 120ppm
CH: 240ppm
CYA: 90ppm

So, PoolForum, what would you suggest for fixing the chlorine and clearing up the minty-green cloudy water? Are we close to having it fixed or would you recommend dumping and refilling?

Thanks!

As long as you still have green in the water, you haven't killed all the algae yet. With a CYA of 90, you need to shock the pool by taking your chlorine up to 20 ppm and hold it there by testing and adding more chlorine as often as possible. You need to maintain that 20 ppm level of chlorine until the pool clears all the way up, and until you can go from sundown one night to sunup the next morning without losing more than 1 ppm of chlorine. At that point you can let the chlorine drift back down, but with the CYA that high, you can't ever let it drift below 5 ppm. (See the "best guess chlorine chart" in my sig for the details).

I suspect the "shock" they're having you use is dichlor, which contains CYA. Your CYA is high enough already, and adding more CYA just means you have to raise your chlorine higher. So I would use plain, unscented bleach in this case.

Unfortunately, the "green to clean" contains ammonia, and ammonia can create quite a large chlorine demand in your pool, in addition to what the algae is using up. So...it may take several days to get to the point where you are holding your chlorine overnight, but it's a necessary part of clearing up the mess.

Please take a minute and add your pool's information to our pool chart. This will make it easier to help you clear this mess up!

Pool Chart Entry Form

Hi all,


Thanks for your help. I forgot to mention earlier that I had put my info in the Pool Chart.
Anyway, it sounds like from what aylad said, it'll be possibly several days to clean up the water, so we're going to dump it and start from scratch following the Intex pool instructions on PoolSolutions.

However, is there anything we need to do to the pool once it's empty to make sure there isn't any residual algae that would contaminate the new water?

Thanks again!

Hi,

We've dumped and scrubbed our pool and we're now refilling following the directions in the 'Super-simple pool chemistry recipe for Intex type pools: start-up & routine care' thread.
We're starting with bleach as per the thread, but we've got dichlor on hand--should we be using that now or wait 'til the pool is full?

Our info is in the Pool Chart and the 'Super-simple...' thread mentions you'd help calculate a regular dosing plan--that would be a great help!

Thanks!

PF17 -- 1 gallon of 6% bleach will add ~8ppm chlorine; 1lb of dichlor will add about ~9 ppm of chlorine and ~8 ppm of stabilizer.

To start, daily doses 1/2 lb of dichlor would work well -- about 1 cup. If you could add 1/3 in the AM and 2/3 of the cup at night, that would be best. After you've added 7 lbs of dichlor total, you should have CYA=~50 ppm.

At that point, you can switch to bleach if you like -- probably 1 pint daily, depending on bather load.

Use the Best Guess chart to determine appropriate chlorine levels. Higher stabilizer levels allow you to 'store' more chlorine in the water, and allows you to switch to dosing ever 2 - 3 days. If you want to operate that way, continue with the dichlor, until you've used about 14 lbs (110 ppm CYA).

Please note that there is no absolute dosing plan - actual use will depend on your weather, swimmer load, and so on.

Thanks so much for the info!
We think our initial algae bloom started after a rain storm and it's supposed to rain tomorrow (as we're filling the pool)--any advice or concerns about rain causing a new algae bloom?
Also (last question :), the 'Super-simple...' thread says to "Add 1/2 dose (of dichlor) before each group swims"--is that in addition to the dosing plan that you just outlined? How big is a "group"--we're a family of 5, so do we add dichlor each time before we go in the pool?
Thanks again!

The rain doesn't cause the algae bloom--the reason that a lot of people have algae after rains is because they're not as diligent about testing and keeping their chlorine levels where they need to be when it's raining as well as they do when it's sunny outside :)

Until you have stabilizer in the water to the point where you're able to maintain a chlorine level all day, then I would add that half dose of dichlor before a group--even a family of 5--swims...

Thanks for all your help--we'll be diligent this weekend! :)