Cleaning neglected cooling tower screens [HD]

Actually they were not deliberately neglected. Once heat of summer hits I need to try and make it to the end of summer to do a complete thorough cleaning of the entire towers. I couldn't quite make it as the black slime started to take over rather suddenly (need to shock it with some Chlorine) and were restricting the filter screens. The small mesh filter screen at the pump was the real culprit and more of a pain in the butt. I have to clean it about every 2 months but I tried to make it until the heat of the summer was over. This week the pressure dropped on my pump discharge and this AM was a nice drop in temp. Next month I will shut down each tower one at a time to do some major cleaning.