Foam in water fountains can be a problem if you have undissolved organics in your water.  Typically, foam is simple to get rid of with No More Foam for fountains.  This fountain care product is great for table top and other indoor fountains and outdoor patio ponds or fountains.  It will eliminate foam in your fountains fast and it is safe for fish, plants and wildlife.  You may also see an occurance of foam if your fountain is located in direct sunlight as undissolved organics may be higher than normal due to faster evaporation rates. 

• Eliminates Foam in Seconds. Treats up to 480 U.S. gallons
• Safe for Fish, Plants, Birds, and Wildlife
• 8 Fluid Ounces Shake Well Before Using.

Ronna Staley -
I use No More Foam in our large wall fountain. It quickly removes foam and keeps the fountain clear for 1-2 weeks. I have not found a similar product that works this well.