Propane tank and hose help

Ok gang here is my problem. I have the grill in the pic and use it regularly, I have used the green bottles and it works great. I am tired of going through so many bottles, so I got out my 20 lb tank and hose I use for ice fishing, hooked it up and thought it would be great. just the opposite. I am on the second hose from the store and still the same problem. hardly any flame and or heat. even with the hose hooked up and the tank fully open, I still can barely get one side of the burners to burn above a very low flame. I even re hooked up the green bottle to make sure I was not making a mistake. then re hooked up the hose and big tank and again nothing. can anyone offer any usable advice that I might try to make this 20 lb tank hose and grill work like it should. sorry to ramble
Thanks for your help.

Are you connecting a hose with a regulator in it to the grill? Your grill may have its own regulator behind the threaded bottle connection and could be hindering gas flow.

another thing about regulators. Some have a safety function built in. that is if you open the tank valve to fast or to far the regulator locks out. limiting the amount of gas allowed out

I agree with Tom, you have two regulators fighting each other.

I have a Coleman roadtrip and it has it’s own regulator. I hook a plain supply hose between the 20lb tank and the connector to the grill, no regulator except for the one on the grill.