We did ours a little differently from the recommended steps you'll see in the other posts - but the basic idea is exactly the same: add lots of chlorine to the pool, filter constantly, backwash often, vacuum the gunk to waste. Repeat. your water will go from a nasty yellow/brown, to green, to clear green, to crystal clear. If you have a low level of Baq, it should only take a couple days. If you have high levels of Baq, it might take several days.

Here's what we did:

Day one (evening): I used a laundry scoop (I suppose it holds about a cup) and I dumped in about 8 or 10 scoops of Cal-Hypo (commonly known as "shock"). Added about 3-4 pounds of CYA (Cyanuric Acid) granules by dumping them into a woman's nylon and tying it to the inground ladder. The water turned a nasty yellow color. Ran filter 24/7.

Day two (morning): Backwashed filter. Water already turning sort of clear green. Added several more scoops of Cal Hypo.

Day two (afternoon): Vacuumed the crap in the pool to waste. Then we disassembled the filter and changed the sand with new sand.

Day three: Water is almost completely clear! Continue to add a scoop of shock now and then, but basically the conversion only took 2 days for us.

I suspect ours went smoothly because we didn't have real high levels of Baquacil to begin with. And we changed the sand on day 2, so that probably helped as well.