The reason you have almost no chlorine is that you don't yet have stabilizer in the water to keep the sun from consuming it. So..until you have enough stabilizer registering (which is going to take a couple of days), you'll need to add bleach 2-3 times a day to make sure you always have at least 3 ppm of chlorine in the pool. In your pool, if you'll take 6 oz of stabilizer and put it in an old sock and tie it in front of a return, it will dissolve slowly over a couple of days. You can give the sock a squeeze a couple of times a day to help it dissolve faster . This should target your pool for about 20 ppm. You really want to get it up to about 40 ppm, but if you want to use the trichlor tabs, they also increase CYA, just not fast enough for an initial dose. So...use the 6 oz to get "some" in the water, then you can use your tabs until it gets up to 40 or 50 ppm. Your pH will probably fall a little due to the CYA addition, but will definitely fall due to the trichlor tabs, so keep an eye on it. For right now, I would go ahead and lower the pH a little, but not lower than 7.6 or so. I would start with a couple of cups at a time, not 9 cups all at once. Add it slowly through the skimmer, breaking up any clumps, give it a couple of hours to recirculate, then test and add more as needed.

Take a look at your trichlor tabs, and make sure they're not labeled "dual actions" or have copper listed in the ingredient list. If so, then take them back if you can, because you don't want to use anything that contains copper in your pool. If they are copper free, then you can use them in a floater--just make sure the floater doesn't float to the edge of the pool and sit there, because concentrated pockets of chlorine and low pH can fade your vinyl.

So...go ahead and add your bleach, then add your pH minus, then hang your CYA sock. If you have non-copper containing tabs and a floater, then you can go ahead and add those too. But for the time being, check your chlorine at least 2-3 times a day and add bleach if needed to keep your chlorine between 3-6 ppm at all times.