President Donald Trump announced a project to transform the Lincoln Memorial Reflecting Pool in April to address leaks and dirty water and paint the bottom "American Flag Blue". But now he's seeing green.So are the companies hired to do the work. One, reportedly tied to a Trump donor and Mar-A-Lago neighbor, received a $1.7 million no-bid contract to improve water quality. Another is set to make $14.7 million to resurface the pool.The renovations were declared complete and the pool was refilled by June 9th. Since then, it has been turning green from algae. On June 16, USA TODAY confirmed that the color was still present and that workers were adding hydrogen peroxide. Images appearing to show blue paint peeling from the floor of the pool were surfacing by June 18.With the basin set to be drained again, we talked to experts specializing in algae blooms to help us understand the science behind Trump's pool problems.Three things have to be in the water, said Patricia Glibert, professor at University of Maryland's Center for Environmental Science. “And all of those — algae, nitrogen and phosphorus, which are building blocks to cells, are already dissolved in natural waters."“Add some sunlight and heat, and the algae will start to grow,” said Glibert. And they will grow fast, doubling in biomass once per day. " over the course of 7 to 10 days you can have a massive algal bloom."Glibert said a darker color for the pool floor could be a factor because it warms water faster. "Many algae grow faster in warmer water, and while it may have been one factor it wasn’t the only one.”Water depth is another contributing factor. “Like all photosynthetic organisms, algae grow in light and nutrients. And if you have a shallow system, the light can reach all of the algae even the bottom of the Reflecting Pool,” Glibert said. As for the hydrogen peroxide treatment, Glibert said it is effective at killing the algae, but it only solves today’s problem. "That algae sinks to the bottom and is going to decay, releasing nitrogen and phosphorus back into the water and some of that algae will continue to grow, so you have a continual problem.”The Reflecting Pool will need continual monitoring of water chemistry along with improved filtration, and perhaps treatments such algaecides or the nano-bubbler, said Glibert."Clearly the treatment they have done so far isn’t enough.”Two companies, Atlantic Industrial Coatings and Green Water Solutions, were awarded contracts for the work. Atlantic Industrial Coatings will be paid $14.2 million to resurface the pool, and Green Water Solutions is to be paid $1.7 million to improve the water quality.USA TODAY reached out to Atlantic Industrial Coatings but they did not return our call prior to publication. A post on the company's website indicated that some areas in the Reflecting Pool will require repairs that the pool will be drained to complete them.Algae blooms have plagued "every pool reopening since 1922," the Department of the Interior previously said in a statement. USA TODAY has catalogued a list of previous efforts to address issues with the pool.Trump rejected a $300 million Biden-era plan to replace the granite, instead deciding to sandblast, caulk and resurface the bottom. Trump has since blamed vandals for the issues with the renovation and drawn attention to the cost of renovation plans by former presidents.“A fraction of the cost and a fraction of the time, and you’ll get a better product,” Trump told reporters April 23 in the Oval Office.Contributing: Jeanine Santucci, USA TODAYThis is a developing story which may be updated.