IonGen System G2. So say goodbye to string algae with the Aquascape IonGen System G2! Ideal for use in ponds, Pondless® Waterfalls. and other decorative water features, the IonGen System G2 effectively kills algae without the use of traditional liquid chemicals. The system helps to control algae growth throughout the entire system (up to 25,000 gallons) by using a microprocessor that sends a signal to its ion-producing probe.