I am a newby on this forum and in need of some help. I have a Intex 18' x 48" above ground pool. We kept a solor cover on it for the winter. All of the sudden the water is green. I shocked it last night without adjusting the ph level. I know, it was stupid. My question is, can I add some ph plus to it now? The ph level is very low and it does not look like the pool shock is working.