I bought an old style diaphram pump for our water tanks (because that's what we had) from a little store in NC and it failed within 24 hours. I did a little research and found that I could use a much less expensive centrifugal pump instead. I bought one (Jabsco) at West Marine and then I called Jabsco and told them what happened. Since they didn't make the diaphram pump anymore, they sent me a new backup water pump AND
for the extra money I spent purchasing the old style diaphram pump they also sent me a new washdown down pump.