I think you're getting a bit confused (not your fault) with terminology. To clarify:
It sounds like you brought your tanks into a DIVE SHOP, which either sends tanks out to a HYDRO SHOP (more commonly, a hydro facility) for the actual hydrostatic test, or does the hydro in-house (not as common). A dive shop, when it gets the tanks back from the hydro facility, will perform a viz, re-install your valve and fill your tank if the hydro facility doesn't do that.
A hydro facility will often accept tanks (with or without valves), perform the hydro test, and return the tank to you as-is.
People "in the know" will sometimes bypass the dive shop and bring their tanks in to the hydro facility directly, in order to save time/money (shops often charge $20-40 per hydro, the hydro facility itself charges $5-15 for the hydro). That's what Oxyhacker is talking about - he's dealing directly with the hydro people. Most regular folks like you and I just drop off tanks at the dive shop, which is a more full-service affair.
It sounds like you brought your tanks into a DIVE SHOP, which either sends tanks out to a HYDRO SHOP (more commonly, a hydro facility) for the actual hydrostatic test, or does the hydro in-house (not as common). A dive shop, when it gets the tanks back from the hydro facility, will perform a viz, re-install your valve and fill your tank if the hydro facility doesn't do that.
A hydro facility will often accept tanks (with or without valves), perform the hydro test, and return the tank to you as-is.
People "in the know" will sometimes bypass the dive shop and bring their tanks in to the hydro facility directly, in order to save time/money (shops often charge $20-40 per hydro, the hydro facility itself charges $5-15 for the hydro). That's what Oxyhacker is talking about - he's dealing directly with the hydro people. Most regular folks like you and I just drop off tanks at the dive shop, which is a more full-service affair.