Max Pro air driven booster pump? Anyone have experience with?

[RM.510bigbore]

I been on the road to buying and learning about booster pumps and high pressure air in general. Haskell boosters seems to be the go to name but I tried contact the company for parts and general inquiries and had terrible customer service. So I won't buy there product based on that. I been seeing quite a few max pro air driven booster for sale. The company is based in Pennsylvania which is a bonus to me. The company at max pro is friendly and seems to have parts and services. I would like to buy a larger booster pump that goes to say 9000 psi and be large and industrial so filling my 5500 psi Scott 75 or 90 min tank is not a strenuous task. It is not much more for the larger max pro units. I seen some refurbished units for $1500.00. Any info appreciated. I would love to be able to compress helium from the large steel tank s at 2000 psi and boost to 5500 psi in my Scott 5.5. I'm in the process of selling old hobby goods to buy a booster pump and then 4500 psi African air ordinance upgrade for my texan. Any info appreciated I want to fill to 5500 psi for my Scott 5.5. Thanks again