No, wait to add the CYA until you get this other problem cleared up. Keep at it per my instructions in post #11 above. In a pool with a CYA level of less than 30, the shock level that you need to be aiming to keep the chlorine at is around 12, though it doesn't have to be exact. In your pool, each gallon of 6% bleach will add about 1.8ppm of chlorine. Use that as a reference to help you figure out how much bleach you need to add each time you test.

Have you bought any CYA yet? Even though your CYA test shows none, it actually means "less than 30." So, we have no way to know if you have 0 ppm or 30 ppm of CYA. So, in order to keep from overshooting, we have to assume you have about 30 for now. So, go ahead and buy about 5lbs. of CYA. 5 lbs. will add a little less than 20ppm of CYA. After it is added --- don't do it yet ---- we'll give it a week and then re-test the CYA and see where you are then. If more is needed, then you can do so at that time. When you buy it (if you haven't already), it may be labeled as stabilizer or conditioner. Check the label ingredients. You want to see cyanuric or isocyanuric acid and not a lot of other stuff. You may be able to find it at Walmart or you may end up having to get it at a pool store. The way to add it is to pour it into the skimmer while the pump is running and then run the pump 24/7 for 4 or 5 days to let it dissolve. OR you can put it in an old sock and hang it in front of a return jet. Give the sock a squeeze every now and then to help it dissolve faster. Move the sock away from the return jet when you add other chemicals through the skimmer.

IF you are going to add the CYA separately (which is what I always do) you will NOT want to use any stabilized forms of chlorine or else your CYA will get too high. So, that means no dichlor shock powder or trichlor pucks.

One more thing, please make a signature line with your type of pool, volume, type of filter and size of pump. Also, put that you have a K-2006 kit. This way, when we are replying to posts, your info will be right there in front of us. Makes it easier to answer questions. Click on the signature link in my signature below to make one for yourself. Thanks.

EDIT to add: If you haven't already done so, please read the Best Guess Chlorine Chart in my signature below. It shows the correlation between CYA levels and needed chlorine levels.