Buy Seaflo Pressurised Accumulator Tank 0.75 Litre at Pro Marine Store, with free delivery to mainland UK. 

Accumulator tanks hold a reservoir of air and water downstream from the pump. The air acts as a cushion absorbing pressure fluctuations and vibrations (which can shorten a pumps life), smoothing the flow and making the system quieter. Accumulators allow the pump to reach shut-off pressure more smoothly with reduces the on/off cycle which give better control of water delivery and extends the life of the pump. Rubber mounting feet for easy installation, Can be mounted at any angle.

• Gives smoother flow and quieter water systems
• Internal rubber membrane eliminates maintenance
• Better control of hot water temperatures
• Longer pump life and lower battery drain
• Simply fitted to new or existing systems
• Inlet Port : 1/2" MNPT
• Air Fill Valve Standard automotive style tyre valve
• Pre-Charge Pressure PSI/BAR 10 / 0.7
• Max Operating Pressure 125 / 8.6