We just put up a 15' x 42" Intex pool a few weeks ago. I didn't know you had to use shock to get the chlorine at the correct level for a new pool. I just put the chlorine tablet in the floater, but the chlorine level always registered as low. Once I shocked the pool, the chlorine was at the correct level. You can buy shock at a pool store or KMart. The directions will tell you how much to put in based on the gallons in your pool. My pool holds 3110 gallons. Once I shocked, I also needed to add PH increase as my PH level was low. So far, I haven't had to add alkalinity increase. Do you have the test strips to test your chlorine, PH and alkilinity? I have also been adding the algacide once per week. We run the filter from 5 to 8 hours during the day. The pool is partially under the trees, so we have a lot of stuff dropping in it.
We got lucky setting up our pool. Our yard is pretty level. One side is about two inches lower than the other, but it hasn't caused any problems. The kids are having a lot of fun in the pool, but it's still a little cool for me.