You must have a reliable way to test your water (not strips). If a wall mart in your area has the HTH 6-way kit, buy one. (Check availability) If not, pick up a cheap OTO / Phenol Red test kit.

Order a Taylor K-2006 (no substitutes) - you can find it throgh the links in this forum's moderators sigs.

With no stabilizer, your shock level is 10ppm FC according to Ben's Best Guess Chart.
You'll need a gallon of 6% household bleach to get to 10ppm but it won't stay long. I'd start with a gallon and a half but no more.

Test and add chlorine as often as you can (but at least twice a day) to keep your FC at or above 10. The OTO test won't directly read 10, dark yellow (darker than the comparator's top) is close enough. If you get to orange on the OTO without stabilizer, you've gone too far - stop adding bleach until it comes back to yellow.

Stay on top of this, when fighting algae, if you you're not winning, it is.

Run the filter 24/7 and clean it as necessary. You can shut off the SWCG for now, we'll deal with that after the pool's cleaned up.

You'll need 2-2.5 lbs granular stabilizer. Put it in an old stocking and hang it in the pool in front of the return to the pool. Squeeze it every couple days to help it dissolve. If you get the k-2006 or the HTH 6-way, don't try to test for CYA for a week, this stuff disolves very slowly.

Get back to us with your test results and what you've done.