trying to switch to chlorine, having major problems!!

Help! OK here is my story, bear with me. Just bought the house last summer, pool was already closed for us. Opened this May, found out it was a baquacil pool, decided to try it out, hated it, cloudy water,mold on the sides etc, decided to switch. Pool is 2 years old 19,000 gallons, vinyl, kidney shaped.

We are having major problems converting, we contacted a pool place, they started the conversion for us and left us in the middle of it. We started adding shock ourselves, taking the advice of a local pool place. The water kept turning brown when we put the shock in. They said it was b/c we probably still had baquacil in the pool. The guy gave us non chlorine shock to put in and something else (called "pool magic" I think). told us to keep vacuuming, backwashing, running the filter and we did. The pool started clearing up and we thought we were in the clear! This past weekend we noticed some algae. We added algaeside, but that did not help. Pool water kept getting cloudier and cloudier. I went to get the water tested yesterday and the baquacil levels were gone! He told us to start adding chlorine shock again, and we did. (3 pounds) The water turned brownish again and when I tested it with a strip this morning, it did not turn any color, it stayed white.
We have not added any chlorine tablets b/c they told us not to. Why can't we get a chlorine reading? Should we change the sand in the filter? I am at a total loss, no one can help us and i'm spending all this money. I would appreciate any advice at all!
Here were my readings from yesterday's test:
FAC 0
PH 7.6
TA 80
CA 206

Please don't double post new threads. We will see them and address them if we can. I've answered the other thread.

sorry...i didn't realize there was a rule against that. I am just frustrated and trying to get any feedback as I can. Thank you for answering my other post.
I think we are going to try the bleach.