OK, I am slowly, but surely losing my mind here and hoping the wonderful folks here will be able to help me out.

We have a 22,000 gallon inground pool with a sand filter.

When I initially opened the pool and got to work on it - the usual removing debris, shocking it and of course backwashing I managed to pump out a lot of the filth. Sure enough the pool started to turn in my favor and I thought I was on to something.

I have what I can only imagine is an extraordinary strength of algae in my pool and no matter what I do, it just won't disappear.

There are parts of my pool that are blue and I can put that down to when I was skimming and scooping leaves and debris from the pool, at the same time I was also removing the algae with the net. However, the rest of the pool is green and also has what appears to be a yellowish stain around the water level.

I had the water tested at the local pool store and everything was within the normal range (I don't have the result to hand, although I do remember my ph level was 7.6)). I explained my situation to them and even showed them the pictures I had on my phone. They recommended I use algecide to help combat the problem.

Well, after using that there was no change whatsoever. I have been vacuuming the pool and brushing it for 4 days and nothing is moving. I have never had this problem before ever and I am becoming increasingly frustrated. Usually when I have added the chemicals to clan it up, when I backwash the water mes out all dirty. Now when I do that, the water comes out clear.

I have photo's for anyone that might be able to help