Return from Vacation

[cschnurr]

I have a 96,000 litre pool with SWG.
We had a great 2 week vacation to the Canadian Rockies and left a friend tend to our pool.

Prior to vacation, I had the SWG maintaining Cl around 3ppm, cc was always 0.

Cl was maintaining and pH increasing per usual. I had instructed my friend to add some pH down if it climbed above 7.8, which he did not add until Thursday (11 days into the vacation). I'm guessing he added about 2 kg.

On Friday, he noticed it was cloudy with algae, so he added some Cal Hypo.

This week temps in Ontario were over 100F. My timer is on 8am-noon, and 5pm-9pm which has worked all year for me so far. Is it possible the the Cl depleted during the afternoon and initiated the algae.

When we returned today (Saturday) the pool was cloudy with visible agae.
The readings are
FC 5.0
TC 5.0
pH 7.5
TA 100
CH 350
CA 55
Temp 82F.

I verified the Cl 3x because I'd thought the CC must >0.

I plan on increasing adding bleach to increase FC to 15 per Ben's Best Guess chart (does this still apply for SWG's) then vacumming 24/7 with regular backwash while maintaining at 15ppm until algae disappears.

Would the pH drop contribute to the algae formation?
Any other suggestions?

[CarlD]

You are taking the right steps to clear it.

The pH dropping would not encourage algae. Lowering pH makes chlorine more effective. Raising pH lowers chlorine's ability to kill bad stuff.

[sevver]

I am never going to go on vacation. Can't anyone handle a pool? Nothing like coming back from vacation to a total mess of a pool. I would send the caretaker a thank you card, and offer to take care of anything of theirs whenever they need it.
Wow.

[cschnurr]

I am never going to go on vacation. Can't anyone handle a pool? Nothing like coming back from vacation to a total mess of a pool. I would send the caretaker a thank you card, and offer to take care of anything of theirs whenever they need it.
Wow.

To be fair, I think he did the right things, adding acid and chlorine, but wouldn't have been checking everyday as per my routine.

I'm wondering why would cc=0 yet I have visible algae and cloudy water, and is it safe to swim in 15ppm Cl.