I have a sand filter with a side mounted multi port valve. The filter has a clear plastic top (screw cap 12" dia) with a pressure guage on top of it. When i backwash the water in the filter top/cap turns brown and after a few minutes not 45 second clears about 80-85%. i also have a site glass near the multiport valve on the waste pipe. This site glass (about 1" dia never looks dirty. When i rinse about 45 seconds the filter top clears up nicely.
My question is should the site glass look dirty same as the filter top glass?