u/Lower_Pay7695

The waterfall feature is not working. I tested and the pump is working properly however the water is not running from the bottom to the top. Last year i had the same issue i had a guy clean up the entire pond pressure washed and it started working but again it stopped. I just do not have the money to get it cleaned again. Any suggestion where i can check ? I am willing to myself just dont know where to start. Any help is appreciated. Picture for reference.