Cloudy Water out of nowhere

[columbusdan]

I got the pool running about 3 weeks ago. The only chemicals I had to add (starting with fresh, brand new tap water due to a new liner) were bleach and a little muratic acid to bring the PH down slightly. I also added one bottle of Leslie's stabilizer which brought my CYA up to around 30ppm.

I have two boys (8 and 10) who have been the only ones swimming, with an occasional friend. They have probably swam (word?) 5 times in the last two weeks. I have kept an eye on things after I got readings where I was happy, adding bleach when FC started to come down. I have had crystal clear water until this point.

Yesterday, I came home from work and the water was cloudy. My wife says it was clear when they took cover off, then became cloudy after boys got out of pool. It had been a while since I added some bleach, so without testing, I just added a gallon.

This morning, water is still cloudy. I can see bottom drain cover in deep end, but it is not clear by any means. I tested the water and here is what I got:

FC = 6.5
CC = 0.5
PH = 7.4
AK = 70
CYA = 30

After reading some other posts on cloudy water, I am thinking 1 gallon of bleach was not enough to "shock" the pool...is this correct? I can't imagine I am at the beginnings of an algae bloom already...air temp has been around 80 the last week or so, no rain, pool temp started 3 weeks ago around 68 and has gradually crept up every day and is sitting around 82.

The pool is in ground, 12x24, with about a 7 foot deep end, approx. 10,000 gallons. Has vinyl liner. Has cartridge filter.

Thoughts?

[Watermom]

If it had been awhile since you added bleach, then yes, you probably are on the verge of an algae bloom. Especially with water temps in the 80s. It doesn't take long. You have to be very diligent about testing and adding bleach consistently. Pool water is not very forgiving. Even a short time with the chlorine dipping too low and algae can start.

Most bleach is sold in 121 oz jugs, not a full gallon. One of those jugs in 10K gallons will add about 7.8ppm. Each quart will add about 2ppm. Use those values as a reference to help you figure doses.

Run your pump 24/7 and go ahead and take your chlorine a little higher.

[columbusdan]

Will do, thank you for the input.

[Watermom]

You're welcome! :)

[columbusdan]

How often should I expect to have to add bleach, assuming my kids swim 5 days per week? I know I will have to really watch it if we have a lot of people swimming, especially in such a small pool. Every other day?

[Watermom]

Depends on how high you take your chlorine each day and what your CYA is and what the weather is like. You'll just have to get to know your pool. If I was you, I'd take my CYA a little higher--- up to about 50ppm.

Each evening, test your water and add enough bleach to get the chlorine back up to 6ppm. The next evening, see what your chlorine level is when you test in the evening. Again, add enough bleach to take it back up to 6ppm. After a couple of days of doing this, you'll start to see how much is a normal chlorine loss for your pool in a day. You may find that you can skip a day and add bleach every other day. You want to make sure you keep your chlorine in the proper range per the Best Guess Chlorine Chart (in my signature below).

[columbusdan]

Followed your advice and had clear water again the next day. Been trying to keep FC up around 6. Out of curiosity, why take CYA to 50? Less loss of chlorine to sunlight?

[Watermom]

Good question. Most pools with CYA less than about 50 have trouble keeping a chlorine reading throughout the day, especially when it is hot and sunny outside.

Glad your pool cleared up!

[columbusdan]

Should I buy some of that granular stabilizer (HTH from Wal Mart) or a small (very small) bucket of dichlor tabs to get it up? From what I have read, that stabilizer stuff can be a pain to dissolve. I will NOT buy another gallon of liquid stabilizer from Leslie's. While it was nice to instantly get it dissolved, not worth the cost. I have to move it 20ppm in 10,000 gallons.

[Watermom]

Either way will work. Personally, I just buy granular CYA for my pool. It's not that big of a deal. You can put it in an old sock and hang it in front of a return jet. Give the sock a squeeze every now and then to help it dissolve faster.

[JimK]

I also use granular CYA. I just add it slowly in the skimmer and let the pump run continuously for 24hrs or so. Based on my own testing this seems sufficient time to dissolve the CYA.

I've read some posts saying it can take a week to dissolve CYA, but I have to wonder where that info comes from as that's never been the case in my experience.

[Watermom]

You kinda want to err on the side of caution ---- making the window longer than it probably needs to be before retesting so that you don't: 1)waste CYA testing reagent
2)think your CYA is all dissolved, decide it is too low and add more and then end up with too much.

It is easy to add more CYA but hard to get rid of it if you have it too high.

[JimK]

You kinda want to err on the side of caution ---- making the window longer than it probably needs to be before retesting so that you don't: 1)waste CYA testing reagent
2)think your CYA is all dissolved, decide it is too low and add more and then end up with too much.

It is easy to add more CYA but hard to get rid of it if you have it too high.

Good point. :)

[BigDave]

Should I buy some of that granular stabilizer (HTH from Wal Mart) or a small (very small) bucket of dichlor tabs to get it up? From what I have read, that stabilizer stuff can be a pain to dissolve. I will NOT buy another gallon of liquid stabilizer from Leslie's. While it was nice to instantly get it dissolved, not worth the cost. I have to move it 20ppm in 10,000 gallons.Tabs are usually trichlor and, like granular CYA, are slow to dissolve.

Dichlor is usually granular and dissolves quickly, 1lb of pure dichlor will raise your pool's FC by about 6.5 and CYA by about 6. If you use it for daily chlorination, three or four pounds will get your CYA in range. Accept nothing less than 99% dichlor (55% available chlorine) There's lots of junk on the market some of which adds copper.