A little baffled

[TrevNJPool]

Ok, just got home from a week long vacation. I came home monday and did a quick check on the chlorine level since I had my new timer installed and the chlorinator putting chlorine in the pool. On Monday the FC was 9. I figured that was good since noone was here to monitor the pool. I just got home and did another Round of tests.
FC 10
Cc less than .5
TA 90
PH 7.0 - 7.2
CYA 30 might be a bit higher from the trichlor tabs all week
I did have a little algae on 1 side of the deep end wall which came right off. I, m assuming that is because it wasnt swam in all week and the solor cover was on.
My question is this, If the FC was that high how can algae grow? That level is almost up to slam level and way higher than my target FC level of 5. The water is crystal clear. I scooped out a few leaves and dead frogs but the algae thing has me a little stumped.
I didnt have the jets pointed down which I believe i should have since I didnt have any swimming going on to mix up the water and it probably didnt get great circulation with the solar cover on and the jets pushing the surface. Any ideas?
I forgot to mention that i had the pump run fro 10pm to 2am and 12pm to 3pm daily all week

 

[Smykowski]

Probably poor circulation, resulting in localized areas where FC was too low.

 

[TrevNJPool]

Another question, can u put the solar cover on if u "Shock" the pool? I just put 32 oz of 78% cal hypo I had [raises FC by 6 which should bring the water FC to 16] to kill any of that algae that was lurking around. Not sure if I can cover it after that. Dont want to lose the water temp. Its been getting chilly at night. Thanks again

 

[jblizzle]

It is fine to have the cover on at least at night. But, you do want the pool to breathe for some of the day (lets the CC get burned off).

You do realize we do not "shock" pools right? We follow the ShockLevelAndMAINTAIN Process,

 

[TrevNJPool]

I realize that, but I'm not completing a slam of the pool as of right now. Just raised the chlorine level real high "shock". Dont know what else to call it

 

[jblizzle]

But why raise the FC up "real high" if you are not trying to solve some problem?

You found algae ... therefore you should follow the SLAM process. You may pass in one day, but you will not know if the problem is solved without passing the 3 criteria.

 

[TrevNJPool]

True. After u put it like that. Any thoughts on how algae grew with the fc so high?

 

[jblizzle]

I can only guess like Symkowski that maybe there is limited circulation and a localized drop in FC.