[villagetinker]

Originally Posted by Lyn McElwee

Thank you....this is my sons pool...he has a combined heater and solar heater which handles the pool and spa just fine....about 80 degrees. But he wants an additional heater just to boost heat for the spa...pool companies have given him a large quote for a big heater. He wants a heater less than 100k BTU and knows it will take about 2 hours to get the temp up to 100+...he is fine with that since he works from home.
Two pool companies are trying to oversell the larger heater size and won't get the smaller one.

I do not think this will work, sounds like the water for both are combined, he would need to somehow separate the spa from the pool ($$$$) and then install a small heater for the spa. Depending on how the plumbing is installed and if the spa drains into the pool this may not be possible.