I have been brushing, adding chlorine, testing, vaccuming for 3 weeks. Please help. My pool has gone from green to greyish green. It has been clear all winter - suddenly about 3 weeks ago started to turn. I brought it up to shock level - high 20's, then my husband added chlorine again (he didn't know I had already added) so it was about 40, so I drained and readded until I got it back to around 30 of FC. He took a sample to professional to verify my testing - and all the numbers were really close except the chlorine - they tested 10 - when mine was 30. I retested and verified my results. I am pretty sure I was right- they were wrong.
Pools store said add baking soda - so we did
Still grey water with a slight green tint in the deep end. I have 29000 gallon in ground.
We cleaned the filter (one year old). Filter pressure is 14. I backwask at least everyother day - but usually daily.