Pool turned milky and opaque overnight

[jellybean7]

Since we cleaned up our swamp about a month ago, we've had perfectly balanced, crystal clear water. I did a full test 3 days ago and all the numbers were in range. Daily pH and chlorine tests on Wednesday showed 7.5 and 6ppm. We woke up this morning to a completely opaque, milky white pool. All the numbers are still the same except chlorine which is down to 0. (CC 0.5)

What happened? I'm running out for chlorine now to shock the pool, but I would love to understand what caused this. As I understand, dead algae would make the pool milky, but I never had anything but clear water.

The other numbers are:

ph 7.2 (this had been hovering at 7.5 until this morning)
TA 110
CH 230
CC 0.5
FC 0
CYA 40

 

[JohnT]

My first guess is the beginning of an algae bloom. Sometimes cloudy water is the first sign of algae, and 0 FC is an invitation.

The other possibility is something found its way into the pool that clouded the water and consumed the chlorine.

 

[jellybean7]

Thank you for your very quick reply. I'm going to shock to pool now, but should I also get an algaecide, or just wait and see what the shock does?

 

[duraleigh]

Algaecide is not particularly helpful to shock. By far, the best product to shock a pool is Clorox or liquid chlorine.