to Shock or not to shock

[KirstenHW]

I believe mine is doing just that now. We've had lots of rain in Orange County this week (which I tested and is it ever acidic!). As a matter of fact, I will get green starting along the seams of my liner (IG 30-36K) and I can count on my hand the number of times in the past 2-3 years my CC has been .5 - rarely happens.

[ChuckD]

And now I guess I've seen for myself in my own pool.
My numbers are all in line although my Cl is a bit elevated (CYA 45, FC 9, CC 0). Yet this weekend I got in with a mask for the first time and started poking around in the corners and in the deep end and found light traces of green algae! My water's crystal clear (see my post in the IG pool gallery) and after two days in the bright sun no increase was apparent. I brushed it and won't give another thought.
I did notice that the algae seemd to be growing in areas where the currents from the jets weren't moving the water too fast.

C.

[cwstnsko]

I've had the same thing this year. FC always 3-5 ppm, CYA 25-30. Water perfectly clear for 2 years now, never even a trace of green in the water, Never any CC. Small spots of green algae growing in the corners and in a few spots on the bottom. It brushes off easily, but comes back consistently. Shocked a few weeks ago to 15 ppm for 24+hours, algae back about 2 weks later. Phosphates tested at pool store at 3000-5000 ppb, home test indicates 2500+ ppb. Shocked the pool up to 20 ppm yesterday, dropped from 18 at dusk to 16 in the morning. Brushed thouroughly. No CC. Dropped to 10 today. Poured in 2L of Phos-free into skimmer of 13,500 gallon pool with 420 ft^2 cartridge filter, no rise in pressure. Tiny bit of cloudiness within an hour or so, clear again within 12 hours. Time to get in with the goggles and see if there is any algae still hanging around. Will test again for phopates tomorrow, see if the Phos-free did any good.