Just discovered this forum after desperately searching for ideas on what to do with a green pool. Looks like I have much learning to do - Pool School reading, test kits to buy, etc...
Just before I plunge into this, one question. Background: I have been running with a green'ish pool for a few weeks now, after a major rain. I managed to get the water somewhat cloudy, not too green, but then I had to leave last weekend, and I kept the pump off. Now the pool is QUITE green. My pool store told me maybe my sand was old (I bought the house in 2011, and it's just at that shoulder period where I don't know if the previous owner changed sand after 5 years, or was lazy and didn't)... anyway, I changed the sand a week ago myself. Worst experience ever. Sand everywhere. But I digress.
Here's the question. When I attempt to vacuum the algae out, they come back to the pool. My jets are mostly on one side of the pool. What happens is, if I start vacuuming to waste (like if the pool is too full), the water clears up; but then if I switch the filter to "Filter", and continue vacuuming, the muck gets returned to the pool right in the area of the jets. I can see them excreting the stuff I'm vacuuming back in. Is this normal behaviour that will go away once I figure out my CYA, shock the pool and fix the water balance? I verified my laterals when I emptied the sand, and they were perfect - no cracks or funny business. I filled the filter with 6 bags of 50lbs of regular sand.
As far as the green-ness goes, I guess I have no choice but to buy a test kit and see if my water is completely out of whack, so I'll go ahead and get on that.