When it comes to a conversion, any amount of BQ oxidizer or Algistat/Sanitizer is too much. It seems that the more you have, the more "goo" will rise to the surface of the pool. In all the threads that I've read and in my own personal experience, I never saw black water. I will say though that the less you have in the pool, the better.
The last straw for me was the cloudy water. I spent a significant amount of money last year (in the $750 range if I had to guess), and even for the first part of this season ($couple hundred), and I still couldn't clear up the water. So it really depends what you feel comfortable swimming in. Since my conversion, crystal clear water is so much more inviting than a cloudy mess where you can barely even make out the liner pattern in the shallow end, let alone the main drain.
Though timing typically varies,
In my case, and the ones I read in preparation, my conversion was fairly quick. You just have to stay diligent. Test every hour over a couple days and boost the FC level to 15 each time using Pool Math to tell you how much Liquid Chlorine to add. If you are in Massachusetts, go buy about 4 cases or of liquid "shock" at Ocean State Job Lot while you wait for your test kit to arrive. Don't worry about over-buying because you will use it eventually, I have a larger pool, but I went through over 6 six cases in the first 48 hours. I suggest OSJL because they sell 12.5% Sodium Hypochlorite liquid for $2.99/bottle (I don't know what they sell it for at Namco or Leslie's because frankly, I've stepped foot in Namco and/or Leslie's a grand total of once since my conversion and that was to buy a new skimmer basket and sand). Just stay away from the powder or granules. Then follow
How to convert a Baquacil pool to chlorine to a tee.
Oh yeah, if you do decide to convert, take some pictures. They are fun to look at and you will be able to see your progress as time goes on. It's hard to remember little changes when multiple hours pass in between.