California water officials plan to dye McLeod Lake in downtown Stockton starting Monday to study the cause of the waterfront’s notorious harmful algae, a city news release said. Through Friday, crews plan to use a Port of Stockton boat to apply the dye and gather data between Weber Point and Interstate 5, the release stated. Depending on conditions, the lake may turn a pink or purplish color from the harmless rhodamine dye, it stated.  The California Department of Water Resources aims to find the cause of harmful algae blooms by using the dye to observe water flows in the lake and San Joaquin River.