I HAVE 3 4x8 FLAT PLATE COLLECTORS (HOME MADE BUT NICE) USED TO PRE HEAT DOMESTIC WATER. THEY ARE ANTI- FREEZED AND I USE A REPAIRED 39 GAL INDIRECT TANK FOR STORAGE. IT WORKS OK - I GUESS. MY ECONOBURN AND STORAGE ARE NEW SINCE MARCH. I HAVE BEEN READING HERE AND A LOT OF YOU GUYS SEEM TO BE USING YOUR HEAT STORAGE WITH SOLAR. DO I WANT TO CHANGE ? IT SEEMS LIKE BTUS ARE BTUS. I PLAN ON BURNING THRU THE SUMMER AS REQUIRED.