Can't Get Rid of Green!!

[jmjbj_h]

Thanks for the reply, I use a Taylor FAS-DPD Test and do titrate. I used to use Baquagunk but changed my filter and liner last year and went BBB. I test before I pour always. I have been doing it 2 to 3 times a day. My clorine has been consistently that high when I test. About half gets consumed during the daylight hours, maybe more. What am I not doing right??

[JohnT]

Thanks for the reply, I use a Taylor FAS-DPD Test and do titrate. I used to use Baquagunk but changed my filter and liner last year and went BBB. I test before I pour always. I have been doing it 2 to 3 times a day. My clorine has been consistently that high when I test. About half gets consumed during the daylight hours, maybe more. What am I not doing right??

If you have algae AND no CYA, you would have to add chlorine almost hourly to maintain any kind of FC level. Maybe you've killed it. The water turns blue-gray when the algae dies, and maybe liner color or pollen MIGHT be throwing the color off.

The sun is probably eating it during the day, but if it holds overnight, I can't imagine you have any algae left. Have you considered that it could be a copper issue?

[jmjbj_h]

I thought of the copper, but I can't think of where it would come from. I put in poly at closing and that is the only think I have done different. How would I know if that is the issue?

[chem geek]

My best guess is that your chlorine got used up over the winter and the PolyQuat 60 lasted for a while and then also got used up. When that happened, the algae could take off. Also, bacteria consumed the CYA producing ammonia which made for nice algae food (algae need nitrogen -- typically from nitrates, but ammonia will do nicely).

JohnT is right that without any measurable CYA any chlorine you add will get cut in half in about a half hour in direct noontime sun. I suggest you add Dichlor granules/powder since that will add both chlorine and CYA. You don't want to add too much. It takes 3 pounds of Dichlor per 10,000 gallons to raise the FC by 20 ppm and the CYA by 18 ppm. So I would add enough Dichlor to cumulatively add about 20 ppm of FC since the 18 ppm CYA should be enough to keep the chlorine from burning away too quickly (you can always add more later). Look at this post for some brands of Dichlor if you don't know of any.

Then, hit the algae hard with bleach or chlorinating liquid, maintaining the FC level at a minimum of 10 ppm FC though you could target 15 ppm to make things go faster.

JohnT may be very right that you have copper that has precipitated at the high pH which would make any gray/white cloud (of dead algae) look green. However, the dead algae should filter out and breakdown from the chlorine if you run the filter 24/7, expose the pool to sunlight, and keep the chlorine level high (you might clean the filter, especially if you see a rise in pressure). If your pool doesn't start to clear in 48 hours, then we can look at other things. By the way, what is your CH level? Maybe the TA, high pH and a high CH has your pool cloudy from calcium carbonate.

Richard