The precise level of sand is not critical. If you remove the mpv (that's the valve), you may find a mark on the inside of the tank. If not, don't worry. Make sure your sand is around 2/3 full. All you are doing in making sure it is not excessively low (like 1/2 or less)
That you brushed the sides and got some "dust" is a good thing again.........you're making progress.
Keep doing the SLAM.......I think you are getting closer and closer to a clear pool
That you brushed the sides and got some "dust" is a good thing again.........you're making progress.
Keep doing the SLAM.......I think you are getting closer and closer to a clear pool