OK, I think I can officially make the announcement….
Touch wood I now have a Trouble Free Pool! Thank you all. I would like to finish up this thread with a few comments in case there are people out there pursuing the same goals and facing similar challenges while trying to change over from a ‘pool shop pool’ to a ‘Trouble_Free_Pool.’ This thread may be of use for future readers too.
Almost 2 weeks post SLAM- Pool is clear, and staying clear! Chemistry is stable, in particular FC. SWG is adding 2-3ppm FC a day, minimal (if any) loss each night. I’m still testing FC twice a day at least. I’m heading into pool closing in the coming weeks, so the sun is really leaning down, minimising lose to sunlight. Going to leave CYA @ 50 until spring.
It took me over a month and 3 slams, but I got there. I should have done the first slam like the last! I have learnt a lot along the way, all from this website. Done properly the SLAM level should be maintained for days,even after you think you have got it. Also scrubbing and cleaning everything when the pool water is at elevated SLAM level. Paying particular attention to the filter cartridge and housing/ pump basket, skimmers, everything, blankets, toys, lights, drains, everything is suspect!
My first attempts at a SLAM where not followed through properly. Perhaps a SLAM at CYA 75 with a SLAM FC target of over 30 was problematic in maintaining with my level of experience. From what I understand the MAINTAIN part of the process is critical in ensuring the algae is destroyed faster than it can multiply. The high FC slam level is required to speed up the killing so the Algae cannot reproduce faster than it is being wiped out. Maintaining a high FC level is important to completely ‘sterilise’ the water. I have since learned that you don’t have to necessarily raise the FC level to kill Algae- Algae is killed at low FC levels too, just no where near as quickly, as like during a SLAM.
I’ve read through all the forum posts by Chem geek from 2007 and feel I have an excellent understanding of the relationship between Chlorine and CYA. Very well written, researched and put together in such an easy way to understand. I’ve read it all! That person (Richard I believe) deserves recognition for what he has compiled for the community, thank you.
My basic understanding- A Chlorine/ CYA ratio of 20% has far less active chlorine that a pool with 3ppm FC and zero CYA.
Until I really get my head around my pools needs of FC, I’m happy to target anywhere between 7.5-20% ratio. The water feels fine, no chlorine smell/ feel at all observed by all swimmers. My focus now is % of FC to CYA, not FC alone. I realise I may lose more FC than if I was running it lower, but I will look more closely at this next season.