Helping a friend...

[Karifoy]

I've been maintaining my pool beautifully all summer, thanks to TFP. So now I guess I'm qualified to help my friend get out of a jam that her "professional" pool guy has gotten her into. I went with my Taylor K-2006 kit to check things out, and found her 25,000 gallon plaster pool with green walls, no free chlorine, CYA 110, pH 7.8, alkalinity 140, and CH = 0. They are draining half of the water out now and we plan to SLAM tomorrow once it gets refilled. I have never used cal-hypo before, but I'm assuming that since they have no hardness, cal-hypo would be a good choice? Any thing I need to be aware of before using cal-hypo to slam? I also assume they can use it to maintain residual until CH reaches the desired level, and then switch to bleach? BTW, we are in SC and they leave their pool open year round.

Also, the pool guy had already talked them into buying some Clorox Green Algae Control. She hasn't used any, but since they have a bunch sitting around, i was wondering what it is, exactly, and if I have any use for it? Or should I just advise them to take it back? It sounds like the pool guy was trying to tell them that the phosphates in their well water is causing the algae. I did my best to explain to them that phosphates don't mean a thing if we can maintain a residual.

Thanks guys!

 

[Texas Splash]

Well, we all know that algae control is gained by the proper use of chlorine, not phosphate removers or anything like that. While Cal-Hypo is fine when CH is low, I'm not so sure you want to rely soley on that to increase CH from zero. (wow - zero). I would tend to lean towards the following steps:
- Complete water exchange and confirm new CYA
- Adjust pH first in preperation for the SLAM
- Add required amount of CH increaser perhaps just to minimum level required
- Start adding FC to SLAM as required based on the CYA level
I would think the Clorox algae control could get returned, but let others confirm as well. Also, left-over Cal-Hypo is fine to use form time to time, but perhaps after the bulk adjustment has been done. You can use the Poolmth calculator (at the bottom) to see how much Cal-Hypo effects your pool levels.

That's my initital thoughts. Let's see what others have to say.