when the pressure is high on filter mode it usually means that a backwash is required.

No this has waterin it when it is in backwash mode and rinse mode otherwise it is empty.

To play hard mode, go to missions, then select hard.

Backwash valve is leaking by. More than likely it is a bad oring inside the valve. Or it was not place back into recirc mode completely.

or

you may have a leak on the return side of the filter. That includes all the plumbing from the filter or heater to the pool. The back wash valve may be obvious if the waste line ends close by. The back wash valve should be placed in the "filter" mode not the "recirculation" mode.

K

There wont be any dirt under the sand. When you vacuum your pool you should do it on filter mode Otherwise you will lose a lot of water for nothing, this would be especially wasteful in the case of a salt water pool. Ofter having vacuumed the pool on filter mode and if the pressure gets too high backwash. after backwash rinse for a minute, then return to filter.