Thanks guys for all the input. I think Amoque has a point which is supported by Dave. I’m not worried about controlling power for any AC cycle but controlling the on-off function of the SSR for say an on cycle of 5 seconds or 5 minutes so I use a pulse stream like Henrik displays in his illustration for 5 sec. or 5 minutes. After which I monitor the temp change. I’m sure a relay would do the job just fine except I don’t want to have to replace a relay every other year. I’m sure it will take some experimenting to get the on-off times worked out depending on the volume of the water. A PID is most likely overkill. I see now there are many ways to control this function. Thanks again, you guys are awesome.
Wayne