Hi Pete;

I'm glad it worked for you. But, I wouldn't recommend it for ANYONE else. Here's why:

Most boilers used for home heating use recirculated water. In some cases, this water is treated with toxic chemicals, which help protect the piping, but don't hurt people . . . . because people are never in that water. In other cases, the piping & boiler are corrosion resistant, so long as not too much fresh water is added, but that water will itself become metal contaminated. And there are still other cases.

The bottom line is: if someone knows enough to KNOW that they can do what you did, without damage to their pool or heating system, then they won't need to ask how to do it here. But, if they do ask, we have to assume that they do NOT know, and don't have the skill to determine whether they can, or not.

There are many things I've done on pools and with pool equipment that I'd never mention here, because they are "don't try this at home, unless you are an expert" sort of things.

What you've suggested worked well, and economically, for you. That doesn't mean it's appropriate for someone who may know know whether they have a steam or hot water system, or whether their water make up control is capable of feeding a pool without damage.