That is about the right amount of CYA to get you to a level of around 40ppm which would be good. So, don't use the dichlor. Just stick with bleach.

If you can't find muriatic acid, you can always buy pH down and use that.

For the next 4 or 5 days until that CYA gets dissolved into the water, you are going to need to add bleach morning and evening. If you let it drop down so low, you are going to get algae. After that, you should be able to go to testing and adding bleach in the evening only.

If you haven't already done so, do yourself a favor and buy the good kit we recommend -- Taylor K-2006 or 2006C. (Link in my signature below.)