Sand filters usually have a pressure gauge in front of them indicating the back pressure before the filter.When the filter needs to be cleaned this pressure gets high. usually it has a red section on the gauge. When it hits the red it is time to think about back washing. If the gauge does not work as so often happens with these things. you can usually judge it from the lack of suction coming from the filter. After backwash you will note the pressure will be down and the suction will be up.
It should be on filter and don't forget to backwash at least once a week.
It should be on "FILTER"
No you only backwash your pool when your filter pressure on your filter is high 30psi and above on most pools. If you backwash your pool be sure to add two scoops of de to your skimmer. If the presure is still high the u need to clean the filter
about an inch below the TOP of the filter...there should be a line on your filter...
YES it should be no problem
The pressure gauge will generally read 10 PSI higher than when the filter was clean. In any case do not let the filter gauge go above 40PSI.
Install a new filter
Sure
Zeolite is lighter than sand and smaller than sand. It can get past the laterals and backwash out easier. When backwashing some of it will be in the valve. Rinsing will remove some of it but some will go to the pool.
The best way to determine this is to backwash the filter and see what the pressure is at that time. Then go 7-10 PSI above that and this will be your pressure to watch to tell you when to clean your filter.
Absolutely. Many people excacate and then place an above ground pool into the hole such that a foot or two stays above ground. Also make sure you either have clearance for your filter system or run the line into the ground and up to the filter as well.
Probably not going to be adequate.