I am very new to this forum, as a matter of fact this is my first post. I came to this site because I had to troubleshoot my brand new intex sand filter which was allowing sand by the laterals and into the pool from the very moment of first start-up. I had used the quikrete sand from Menards. It was confusing because this is my first sand filter and I had researched a lot before purchasing and I knew that I had set it up correctly. I got quite frustrated and ended up reading everything I could find about the situation, including a few threads on this forum.
I ended up taking the filter completely apart yesterday and upon inspection I was not able to find anything wrong with any of the laterals. I went to our local pool store and asked if they had heard anything about the quikrete sand being too fine. The guy I talked to stated that he hadn't heard anything about it. I bought a few bags of their sand which did not have any label or brand name that I could find. It was priced at $15/bag which is about double the price I had paid for the quikrete. They promised me that it was good stuff and I would be fine using it.
When I got home I compared the quikrete sand to the sand from the pool store and I could not believe the difference. I should have taken pictures.
After putting everything back together and cleaning out the sand in the bottom of my pool it has been working great with no sand entering the pool.
So, I am not going to tell anyone here what to use but I can promise that I will not be using the quikrete sand again.