Then no need to do the OCLT.
Is it just green, or is there a bunch of organics on the bottom (i.e. leaves etc.)?
- Turn your pump on.
- Add enough baking soda to raise TA to 60 per @mknauss.
- Add 10ppm of liquid chlorine, pump running. Test after 30 minutes. If FC <3, add enough liquid chlorine to get back to 10, test again after 30 minutes. If FC>3 after 30 minutes, then go to the next step. Repeat adding enough liquid chlorine to get back to 10, until FC>3, 30 minutes after addition. Detailed instructions here: Ammonia - Further Reading
- Only after you get FC to hold in step 3, get some chlorine stabilizer (dry) into some socks in the skimmer or in front of a return. Add enough to get to 30. It may be that you will need to do in batches, given the size of your pool. After it has soaked for 30 minutes, squeeze, squeeze, squeeze to get it dissolved.
- Start the SLAM, use CYA of 30 to determine your target FC. Print this out, read it 3 times, follow the instructions and keep it with you. Refer to it often...Link-->SLAM Process