Sorry to hear of your trouble. If you are going to drain and refill, I would abandon the Slam for now. Because you are "blue, cloudy" the algae should be dead. Refilling with water again will likely drop your FC below 10 and allow for pH adjustment. Be sure to retest copper to acceptable levels, then re-commence your Slam and filtering.
This "downtime" may allow some of the dead algae to settle out and let you vac to waste. Please note my post assumes that you are draining a significant portion of your water.
This "downtime" may allow some of the dead algae to settle out and let you vac to waste. Please note my post assumes that you are draining a significant portion of your water.