[Aquamarine]

My source says: HVAC...It could possibly be a passive system whereas the warm water from the evaporative cooling tower is being discharged into the bay producing ideal conditions for algae growth. When you use a closed system you use algaecide and other chemicals to control the algae. Or they could be using seawater for the evaporative cooling tower then dumping it back into the bay.

[TXnMA]

"... the warm water from the evaporative cooling tower is being discharged into the bay producing ideal conditions for algae growth."

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ThanQ!! I didn't see an evaporative cooling tower -- but, I'll look again...

TXnMA
  

[MileHi]

My source says: HVAC...It could possibly be a passive system whereas the warm water from the evaporative cooling tower is being discharged into the bay producing ideal conditions for algae growth. When you use a closed system you use algaecide and other chemicals to control the algae. Or they could be using seawater for the evaporative cooling tower then dumping it back into the bay.

Could be. Then there should be a huge fan (10'-12') that blows straight up in the air (cooling tower). It will be noticeable.

When you use a closed system you use algaecide and other chemicals to control the algae.

Half right. A cooling tower has sides. The side that circulates through the building is a closed loop (just circulates around to get and reject heat. can be used either to heat or cool an occupied space). The other side uses new water (flows in, flows out) to cool the closed loop side. Trouble is, in high humidity areas (an island?) evap systems don't work well at all.