I seem to be confused... When looking for a treatment for yellow algae i see Yellow Treat and Yellow Out. Any advice on the pros and cons on both products?
I know Yellow Treat will consume a lot of chlorine duting treatment.
When CYA gets to 100 or higher you should replace water to bring CYA down again. Hopefully you will never need to do that.
What gonefishin was saying is that your ideal day to day chlorine level depends on your CYA level, as does the chlorine level you need to use if you should need to shock the pool. The more CYA you have the less effective the chlorine is, so you need to add more chlorine to compensate when CYA is high.
No, you shock (elevate your chlorine level) when you have visible signs of algae in your pool or suspect they might be in there. (and some other circumstances, as well, but that's not the point of my reply)
This stuff will all be second nature to you soon.....just keep reading and asking questions.
You are correct about adding refill water to your pool to reduce CYA but, if you're attentive, your CYA will never get that high and you'll never have to do that.