Cooling Tower Balls

Cooling Tower Balls™ are a floating ball cover that controls algae by simply blocking direct sunlight. Eliminating sunlight by covering the complete water surface creates an effective shade factor to control the growth of algae. The pictures below show a case study comparison from cooling towers at an actual Cooling Tower Balls™ customer.

There have been many copy-cats, but RSI is the originator and innovator of Cooling Tower Balls™.  Go to and see who pops up.  While others take short cuts, RSI floating balls always utilize the best, most expensive, proprietary UV block.  This means RSI balls will last.  RSI has put over 3 million floating balls into use.  Cooling Tower Balls™ we have had in use in the scorching sun of south Florida and the Caribbean look great after well over a decade and are still in use today.  The fact is simple, Cooling Tower Balls™ will  control algae and eliminate the headaches, cost, labor dealing with and health concerns of, cooling towers with rampant algae and biological issues.

Starting Day

30 Days

60 Days



  • Controls Algae by Blocking Sunlight
  • Saves Energy
    - sump water is cooler in warm weather
    - sump heaters run less in cold weather
  • Safe for Water and Food Contact
    - HDPE plastic even meets FDA guidelines for food contact


  • Balls Rise and Lower with Water Level
  • UV Inhibitor Gives 10+ Years Service Life
  • Maintenance Free - Easy Installation
  • Made in USA - 100% Recyclable


Approximately 10 balls are needed per square foot of water surface.
5' x 10' sump = 50 square feet x 10 balls per square foot = 500 balls
10' x 10' sump = 100 square feet x 10 balls per square foot = 1000 balls
100' x 50' pond = 5000 square feet x 10 balls per square foot = 50,000 balls
Note: Sizing so there are a few extra balls is fine.  The extra balls will simply start a second layer with added benefits.

Please contact RSI to have a free evaluation conducted on your system.