Cya does several things. Yes it is like sunglasses for chlorine. UV breaks down free chlorine very fast. When it is bound by CYA the break down is slower. It also buffers the effects of free chlorine or takes the harshness from the chlorine. Basically with bound chlorine, you will test higher FC but the effects on the pool, equipment, swimsuits and you are much lower. TFP uses a 7.5% ratio for manual pools and 5% for SWG. As the CYA goes up the FC also needs to go up to keep the ratio. That's why people have problems after a while when they use chlorine pucks. They add both chlorine and CYA. It gets to a point when the CYA gets too high. That's when the pool stores make the big bucks. They sell and sell chemicals and when that does not work they give you terms like chlorine lock and you need to drain. That's the only way to get rid of CYA. The TA is lower because SWG tend to drive up pH. The TA is a buffer for your pH. It's something that really takes some experimenting with. By that I mean, every pool has it's own personality. One pool might like 120 and your neighbors pool might like 80. I would start somewhat low. Watch how your pH does and if it rises fast then make a small adjustment with your TA till you find that happy spot your pool likes. Yes your CYA is low for a SWG pool but I would not do anything until you get your kit. Pool store test vary wildly and it might not be 35. TFP recommends 60-80 for a SWG. The main thing to ask yourself is, do you want a trouble free pool or pool store advice. As you can see they do not mesh. It's one or the other but I can tell you this. You will have the best looking pool if you follow the advise here.
