here are a few factors that can influence the amount of air inside your lilo(s); Significant changes in air temperature The valve has not been correctly tightened There is a puncture/tear If the outside air temperature has dropped or increased in recent days then it is likely that you will only need to top-up your lilo with the provided air pump. Before reaching out to our team, we encourage you to check the valve. There are two parts to your valve; the ‘valve body’ and the ‘valve cap’ Step One:  Remove both the ‘valve body’ and the ‘valve cap’. Check to see if there are any issues with the thread Step Two:  Re-install the valve body making sure to tighten the valve clockwise. Make sure the valve is tight and air sealed Step Three:  Inflate your lilo to the desired pressure Step Four: Tighten the valve cap to the valve body. If the issues persist please fill in the form or reach out directly to contact@oliverjameslilos.com