Gas and Oil Home Heating Furnaces - propane tank sizing question

I put an addition on house and will be putting in 2 fireplaces (one about 40,000 BTU and other about 18,000 BTU) and also plan to put in garage heater (either 45,000 or 75,000 BTU) and pool heater (250,000 BTU) All will be run from propane since don't have natural gas in area. so the real determining item is the pool heater. I had three companies come and evaluate and the first two wanted to put in 500gal tank. very big and likely need to be buried. then it has to go certain distance from home so there is money for excavation and running lines far distance. the last company said I could use two 125gal tanks. they are upright above ground tanks. could be close to house with no excavation needed. the last guy was a master pipefitter (the first two companies had sales people come)so I would hope he knows what he is talking about, but wanted to see if anyone knows if this would be big enough-meaning will two 125gal tanks be able to supply enough gaseous propane to supply the pool heater?