We have a large flagstone patio that is roughly 2 years old. This was our first time to put one of these in but we read a lot of DIY instructions and You Tube videos. We put in a good gravel base (on sandy soil) and laid flagstone in sand. I could have done a better job to level but it looked great when complete. We decided to go with decomposed granite in the joints and it has been a mess since. The granite does not stay in the joints. Our patio has a decent slope to drain but unfortunately it takes the granite with the rain...

I plan to bring in more sand and level the patio and fill the joints with tan Gator Dust this time around. I have read mixed reviews but seems to be most popular as our joints are between 1-4". I also see this EcoSystems that is added to sand that is more permeable... Can't find any reviews on it, however...

Whatcha think??

Here is another pic.