You know I've thought about doing this before. There are PVC fittings that are designed sort of like a compression fitting, that have a rubber gasket to seal around a pipe. If you could find one that seals on your heater, it would be easy to make an inline heater. It think one for 3/4" pipe would probably fit on an Ebo. If you can't find anything that works, you could buy one of the Rainbow Lifeguard units.