Ok let’s start with a very basic theory of operation of the DE filter. You have the filter tank and inside the tank, it has vertical pipes that are covered by mesh grids. When you add DE it surrounds the mesh grids to filter the debris out of the water and the mesh grid doesn‘t allow the DE to get into the vertical pipes and back into your returns going to the pool.
In normal filter operation dirty pool water water enters the tank on the outside of the grids. The water then moves through the DE, through the mesh grids and into the vertical pipes, then the clean water moves out of the filter and back to the pool. Obviously in this process the DE and grids get clogged with dirt. Over time as you have experienced this dirt will plug your filter and slow flow of water back to the pool, necessitating a cleaning of the filter.
To clean the filter we backwash it. This process reverses the flow of the water through the filter. So now the water enters from the pump through the vertical pipes, flows backwards through the mesh grids loosening the DE and dirt, and then moves up and out of the filter through the waste pipe. When this water leaves the filter it carries both the trapped dirt, but all the DE with it as well. In some setups the waste pipe runs to daylight in a yard, storm sewer etc. In your setup, your waste pipe returns to the pool to not lose the water. This is where the separation tank comes into play. In your setup all the spent DE and dirt moves from the filter through the waste pipe and to the separation tank where the DE and dirt is trapped by a mesh bag for disposal before the water travels back to the pool.
Obviously, each time you backwash, the separation tank will fill with DE and dirt. This has to be removed before you backwash again as the system is full. You need the space for the new load of DE and dirt. If you don’t clean the tank, you risk overpressurizing the tank and destroying components when more DE is packed into it during a backwash cycle.
If you don’t backwash, your filter will continue to clog with dirt, you will lose flow, not be able to generate chlorine, not filter the water, could damage your pump, overpressure your filter and blow it up, etc etc etc.….lots of bad things could happen.
Based on your flow sensor tripping out, you know the filter is packed full enough to impede flow. You went from a dirty pressure of 28 down to a clean pressure of 13 after you bumped it. Most manufacturers tell you to backwash at max a 10 psi rise over clean pressure. Trouble free method is 25% over your clean pressure or about 16-17 psi. You need to backwash, it’s routine maintenance. Unfortunately it can’t wait a month, and you’re going to have to work through cleaning the separation tank to be able to do it. The filter is going to keep plugging and flow slowing until you backwash it.
You can do it. You changed out the flow switch, you can do this. Give yourself plenty of time and don’t rush. Read the 8 cleaning instructions on page 1. Look at the parts diagram on page 2 to get familiar with the separation tanks components. Reread both. Ask questions here. It‘s straightforward and not nearly as involved as deep cleaning a filter like you’ve seen on video. Don’t let it intimidate you.
That said, if you wanted to have the tech show you how to deep clean the filter, that can absolutely wait until you get them out to close the pool for you.
. Dang.
. Did you have any difficulty recharging the filter with DE when you finished?