No CYA - How to raise it?

I tested my pool this morning.

pH 7.5
Alk 120
Chl 3
CYA None

How do I raise the CYA without messing up the other numbers? Pool is crystal clear.

You can buy granular stabilizer at the pool store. There's liquid stuff as well but I've never used it and have no experience with it.

Calculate how much CYA you have to add to your volume of water to get the concentration you want. You can use the Pool Calculator to do that. Because I prefer to go slow with chemical additions I recommend to add 1/2 the amount at first, wait a few days, test, and add more if needed. CYA granules are slow to dissolve, hence the wait. Keep adding bleach while you're waiting for the CYA level to rise.

Many people prefer to put the granules in an old sock and hang it in front of a return to help it dissolve. I put mine in the skimmer basket and let it get sucked into the sand filter. I then don't backwash for several days while the compound is dissolving inside the filter.

How do I determine what my CYA should be? I see where some keep their's higher than others. If using granular, can yous till swim while it's dissolving?

Use the Pool Calculator to figure out how much CYA you need to add. You're shooting for something between 30 and 50 ppm. One of our moderators who lives in the South and has full sun on her pool uses 80 ppm (I think). Yes, you can swim while it's dissolving.

Anna's right, I would shoot for around 30-40 at first, but only add about 1/2 the dose, then test in 4-5 days, and add more if you need it. CYA is one of those levels that you want to sneak up on, not overshoot and have to drain water! Once you get to the 30-40 range, see if you're able to maintain adequate chlorine levels through the day. If not, you might need to increase it a little, but the bottom line is that the "right" amount of stabilizer depends on your pool. I do keep mine in the 80-90 range, but I'm in a very hot, humid climate with full sun on my pool all day. Without that high level, I can't keep chlorine in the pool--but the down side is that I have to maintain higher chlorine levels than those with lower CYA in order to keep my pool clear. It's a tradeoff.

Janet

If you decide to add it to the skimmer and let it dissolve in the filter, which is what I do, run the pump 24/7 for 4-5 days afterwards. Do NOT broadcast it across the pool like some containers tell you to. You don't want CYA granules sitting on your liner. And, to answer your question -- yes, it is safe to swim after CYA is added.