Stacked Compressor 25 ton HVAC

An existing 25 ton chilled water system is not controlling latent heat because the distributed water is on average above 45 degrees F. The system has five 5 ton geothermal chillers. In the winter the heat load is typically seven or eight tons. One unit is cycling on and off with a five minute hot start delay. The result is an average water temperature of about 53 degrees. System needs a variable speed chiller or buffer tank.