Ted and Jean,
Your tank is supported by other means. Those straps are there to contain your tank within the RV when the tank swells due to having liquid in it. Honestly, when new, I am not certain how much slack is in the strap with an empty tank. Can you please elaborate on how loose they are? For example, at the center of the strap/tank, what is the gap? Is is a pencil or finger gap or an inch, two or more?
Thanks,
Jim