Algae bloom yesterday, New sand filter and shocked now milky,cloudy water

Hello everyone...

As I stated in the title, I had green water for 2 days, my pool is above ground and only came with a skimmer/paper filter. its 17'x48" don't remember how many gallons. I shocked with hth Super Shock 'n swim in the morning yesterday, and after a couple of hours it seemed to do nothing, so I consulted a local pool place...

They suggested I get the SandPro Game 1/2 horse filter and to re-shock, which I did, not my water is cloudy white.
I tested it (AquaChek Select) and
the hardness was ok (high end but ok)
the total chlorine is low 0.5 - 1.0,
the free chlorine was low 0.5,
the ph was at the high end of ok 7.8,
the total alkalinity was high between 180-240,
and the Cyanuric Acid was ideal at 30-50

I brushed the floor again this morning it produced a light rust color cloud, flushed the filter although it hadn't gained more than .5 lbs. in pressure, and added shock again to get the chlorine levels back up.

How can I lower the pH and the Alkalinity?
What is making it milky? and how do I get rid of it?

There are lots of things that can make it cloudy/milky, dead algae and high calcium being two of them. I strongly suspect that you've been shocking with cal-hypo (is that the ingredient in the Shock n Swim?) and that your calcium levels are too high. That, combined with high TA and pH can make water milky. However, lots of dead algae floating in the pool that needs to be filtered out can also make it milky.

If you had green water for two days, and have only shocked the pool and then let your Cl level come down, I doubt you have killed all the algae yet. To properly shock a pool, you need to raise the chlorine level and keep it raised until you're no longer losing chlorine overnight. With your CYA of 30-50, this means raising your chlorine to 15 ppm. Also, once you're no longer losing chlorine overnight and start to let your Cl drift back down, you need to keep it between3 and 6 ppm at all times. Your filter should be running 24/7 during this time, and you should clean the filter as the pressure indicates.

We really need a good set of numbers, not taken with test strips, and we can help you get it cleared up. At the very least, WalMart sells a 6-way drop based kit for around $20, but we really recommend the K-2006 that can be ordered online through Amato Industries.Their phone number is 800-992-6286.


Lowering pH and Alk are secondary concerns for your pool right now, the first being to get the algae bloom cleared up. When you're ready to lower them, use muriatic acid to lower your pH to 7.0. This will also drop your alk. Then you aerate the water (fountain, turn return streams up to ripple water, etc) to raise your pH back up without raising your alk. When the pH is up into the mid to high 7's again, then use acid to again drop it to 7.0, further lowering alk, then aerate to raise pH back up. It's a ratcheting process that takes awhile, but will work.

Sorry for the very late response, but my work keeps me offline for the most of the week..
Thank you for your advice, I shocked the crap out of it, kept it that way for two days, while back-flushing the filter once a day,
and now my water is crystal clear, there is a fine silt on the bottom, hopefully I will be able to simply vac it up.

I haven't been able to get a better test kit yet, but I will be soon, Once again I thank you for the advice.

The silt -- probably dead algae -- should vacuum up just fine.