DE coming out of skimmer

[brando8912]

This is my first pool and have fixed a number of issues but i want to make sure i have this one right before i go any further.

First off, I have a DE4800 filter and a solar heater.

When i dont have my diverter set to the solar heater, i have no issue. No DE in the pool.

When i have it diverted to the solar heater and my pump shuts off, DE gets pushed back into the pool through the main drain and skimmer.

I have a check valve in between the diverter and the filter and i think this is what has failed but i want to be sure before i replace it.

If it is the diverter, would it hurt it to put it after the diverter going up to the solar heater. It is in a much more accesable location.

Thanks in advance. Below is an image of my setup.
http://i255.photobucket.com/albums/hh151/Brando8912/20160510_183356_zpsyiuowwq0.jpg

 

[gwegan]

We need a picture of the whole pad.

You are seeing de come out of the skimmer and main drain? Frankly that doesn't make sense. Are you saying the solar drains back through the filter and takes de through the pump to the pool?