SAN DIEGO (FOX 5/KUSI) — What is believed to be someone’s decision to pour aquarium water into the San Diego Bay is now causing the Port of San Diego to pour nearly $100,000 into fixing the problems it caused.

“When we want to get rid of our aquarium, the place to dispose of it is not San Diego Bay,” said David Gibson, San Diego Regional Quality Control Board Executive Officer.

The cause of more than a quarter-acre of an invasive seaweed, growing in the Coronado Cays, is believed to be Caulerpa prolifera, a popular aquarium plant. As little as one or two millimeters worth of the weed can grow out of control.

“So I think we’re looking at months to years worth of continued surveillance and control efforts,” said David Gibson, San Diego Regional Quality Control Board Executive Officer.

The seaweed isn’t a danger to humans, but it reproduces quickly as waves and boat propellers break it up and spread it throughout the bay. That can have a devastating impact on an ecosystem – in this case, the eel grass habitat.

“We’re deploying pieces of tarp and broad areas of tarp to control where we found it,” Gibson said.

The tarps block sunlight that the algae underneath needs to grow.

The Port is asking anyone who has a saltwater aquarium not to use Caulerpa prolifera and to only dispose of aquarium water in sinks or toilets where it will circulate to a treatment plant.

The Port also wants boaters, divers and fisherman to learn what the algae species looks like, so they can inspect their gear for pieces of it that may have been picked up, and report sightings to the California Department of Fish and Wildlife.