Oxygen concentrators w/HBOT

Please someone help me figure this out. I recently started leasing to own an HBOT and learned that I also needed an oxygen contcentrator hooked up to it. I purchased a used concentrator that has a 5 liter capacity. Thats what im using right now, but I have heard you really need a 10 liter to be effective. Im not sure if this is just the retailer upselling me or if I really need it. Someone PLEASE help me figure this out. Im fighting late stage LYME and im super sick. Im really hoping the 5 liter is sufficient because a 10 liter OC is thousands of dollars. Thanks for any input!