It shouldn't matter who fills it....only how much was left in it when it was taken in to be topped off. We looked at the tare weight of the tank, (empty weight), and added 20 lbs. to whatever that figure was. The tank was set on a scale while being filled, and the sliding balance weight on the scale was set to whatever the tare weight + 20 lbs. figure was. (Usually 37 or 38 pounds.) Didn't matter who was filling the tank....once the beam on the scale balanced, that was followed immediately by the OPD valve closing on its own and not allowing any more propane into the tank. Keep in mind that that's the *short* way to do it. What's actually supposed to be done, is the WC rating, (water capacity), is looked at. There's usually a chart next to the filling station that shows different sized tanks on it. "20 pound" tanks are usually stamped with a WC of 47.1 pounds. The chart then shows what the propane capacity in pounds is, and that figure is combined with the tare weight in order to come up with a "weight when full" figure. ;-)

We have been talking vent free heaters for years now. I was the one that started it 6 or 7 years ago. Just goto Lowes or Depot or your building supply store or some place that has a heater. Get one! Hook it up, check it and make sure you have the right connections, and your ready to go. You can get propane or natural gas and you can get many different sizes based on your size greenhouse and min low night temps. It todays world, gas is about the only way to heat a greenhouse and feel safe that your plants are ok. Trigger is telling you the truth.

We've done it both ways with no real problems although when critical planting time comes, we tell them to come EVERY TWO WEEKS AND THEY'D BETTER COME AT 10 DAYS RATHER THAN 15. They got the message, of course we were using a lot of fuel at the time with two 1000 gallon tanks and four full greenhouses plus a 500 gallon at the house. Still, you have to keep a watch on the gauges. We just filled up at the lowest cost in the past 5 years. This year we'll start planting a lot later just to save fuel. We continue to fine tune our operation. You might want to change gas dealers. I don't know where you live but around here [in SW'ern VA] there are several to choose from and we're very rural. Check around for prices too---they'll vary a LOT from dealer to dealer. We found that out when we changed companies. Regards, Tom

Is it possible to have two propane tanks, a main and auxilliary, connected to the 'service' point of a home via a 'switch-over' valve of some sort? Purpose would be to use the main tank all the time but switch over if the main tank goes empty and can't be refilled (emergency).