Just for peace of mind, Iwould recheck my numbers if I were you. If these are right, then the most critical thing you need to work on is getting the ph up above 7.0. Readings below that are acidic and can damage your pool. (I'm assuming its an AG pool?) Aim for a ph between 7.4-7.6 although anywhere betweeen 7.2-7.8 is OK. Also get some bleach in there. You can work on ph and chlorine at the same time. You'll also want your alk between 80-125 and baking soda will raise it.

I've not heard that the cya test is ineffective below a certain temp.(?) But you'll need to get some in there. Some people suggest using dichlor to chlorinate with when you also need to add cya but I would just use bleach. Especially since your ph is low. Dichlor is acidic. Hope this helps.