Aquabion S15 Water Conditioner for Improved Water Quality

If using mostly 1 normal flow rate shower at once sometimes 2 the best unit would be the S15. The S20 is for using 2-4 showers mostly at the same time, or very high flow rate showers (15 lpm+). Oversizing the unit will result in poor performance, so happy to workout best size for you if in doubt.If using mostly 1 normal flow rate shower at once sometimes 2 the best unit would be the S15. The S20 is for using 2-4 showers mostly at the same time, or very high flow rate showers. Oversizing the unit will result in poor performance