Hi and welcome to the Pool Forum. In a 20K gallon pool, 5 lbs. of stabilizer is only going to give you a reading of 35 or so. It may be that it hasn't all dissolved yet.
Do you know what the CYA level was when you closed last year? If you had some in there when you closed and none upon opening, it may be that it biodegraded over the winter and you now have a lot of ammonia in the water which is creating a huge chlorine demand.
Another concern is that you are using 'guess strips' and also pool store testing both of which are known to be inaccurate in most cases.
Until your Taylor kit arrives, go to Walmart and see if they have the HTH 6-Way kit or at the very least, pick up a cheap OTO/Phenol Red kit (yellow and red drops). Run the tests and post your readings. While you are there, pick up several boxes of 20 Mule Team Borax (laundry aisle).
In your pool, each gallon (4 quarts) of plain, unscented 6% bleach will about 3ppm of chlorine. Go ahead and add 4 gallons which should take you up to about 12ppm. See if you get a reading an hour or two after you add it.
Repost with some numbers and tell us what kit you buy.
Also, please fill out the requested info in the following chart. It will help us help you more easily.
Pool Chart Entry Form
Pool Chart Results
Bookmarks