Quote Originally Posted by windfix View Post
Wow, thanks for the detailed reply Richard. At least now I understand the variables. If anyone will indulge my new questions:

1. How do you test CYA level? I have never used stabilizer, so I will reference my SWG manual when I get home and act accordingly. I don't, however, know how to test it after I add it. Which leads to my next question....

2. What method is best to test my FC and other stats? I have a little liquid-dropper test kit from a pool store, but I know the chart only goes to 3.0 ppm for FC and we're now talking of ranges up to 15. Plus, a few posts are referencing a test kit that I seem not familiar with.

3. As for pool shock, or maintaining a high FC level until the algae dies - are we talking about dumping chlorine bleach straight into the pool?
Windfix, I just added a little to your MD post, anyway, I'll still say - WELCOME TO THE FORUM! Richard (ChemGeek) always gives good advice, if you ever have a chemistry ? he's one of the 'go to guys' here. Before I start answering your questions, let me advise you to give www.poolsolutions.com a good read (if you haven't already) - it's the starting place for this forum and many of the ideas or 'techniques' that are advocated here.

#1 - Testing cya level is done with a drop based kit which includes a specific test for it, it is probably the dyi test that has the most subjectivity (you and I could do the same test with the same kit on the same water and come up with quite different results - however, we'd have a 'decent' idea of what the cya reading is). Most installers will add the cya when they start up the pool and it tends to stay around (it only leaves the pool via splashout or backwashing/ draining the pool), there are also a couple types of chlorine that add cya with the cl. You most probably have some in your water even if you've never added any, which is why it's important to know how much is in there as it effects the ability of the chlorine in the pool to do it's job.

#2 - The best method of testing is to accurately do your own testing with a good kit (the PS234 is considered to be the best by the folks who use this site [unfortunately, there are some 'irregularities' with shipping and availability right now, but you can order one from the link I gave above], the second favorite is the Taylor 2006, which is available in many places - both can measure up to 50 ppm chlorine (but you can also use the 'shot glass method' with your test kit - a search should find a number of hits)

#3 - YUP! Dump the bleach right into the pool, if you do it in front of an active return, you'll get better/ quicker distribution. It is fine to use with your SWCG as it's the same stuff that you're producing.

I hope that this will at least start to answer your questions, I'd imagine that you can cull some useful info from it and I'm sure that others will 'pop in' to offer more help.

Good luck with your pool, feel free to ask for more info if it's needed.