Use the table below to select the correctly sized item. If you have any difficulties deciding which size is right for you, contact us by email or phone and we will be very happy to assist you. Although many factors including humidity, temperature, stocking density and surface area to pond volume ratio, can affect the Oxygen levels within a pond. We generally recommend a minimum air flowrate of: 100 Litres Per Hour (1.7 Litres Per Minute) / 1000 Litres (220 Gallons) of Pond Volume Or 450 Litres Per Hour (7.5 Litres Per minute) / 1000 Gallons (4500 Litres) of Pond Volume Air Pump | Max Ltrs / Min (Ltrs / Hour) | Max Air Stones | Max Pumping Depth | Recommended For Ponds Up To Ltrs (Galls) | Aqua - Oxy 250 | 4.15 (500) | 1 | 1.0m | 3000 (660) | Aqua - Oxy 500 | 8.3 (500) | 2 | 1.4m | 5000 (1100) | Aqua - Oxy 1000 | 16.6 (1000) | 2 | 1.6m | 10000 (2200) | Aqua - Oxy 2000 | 33.3 (2000) | 2 | 1.6m | 20000 (4400) | Aqua - Oxy 4800 | 80 (4800) | 4 | 3m | 47060 (10350) | Max Ltrs / Min (Ltrs / Hour) Using 5m Of Airline | Immersion Depth | Air Pump | 0m | 0.6m | 1.0m | 1.4m | 1.6m | 3.0m | Aqua - Oxy 250 | 4.15 (250) | 2.16 (130) | 0.8 (50) | - | - | - | Aqua - Oxy 500 | 8.3 (500) | 6.6 (400) | 5 (300) | 3.3 (200) | - | - | Aqua - Oxy 1000 | 16.6 (1000) | 12 (720) | 10 (600) | 8.3 (500) | 7.5 (450) | - | Aqua - Oxy 2000 | 33.3 (2000) | 24.6 (1475) | 18.75 (1125) | 12.9 (775) | 10 (600) | - | Aqua - Oxy 4800 | 80 (4800) | 71.7 (4300) | 66.67 (4000) | 62.5 (3750) | 56.7 (3400) | 15 (900) | |