Hello, I have posted on this site before for those who remember me, I bought a foreclosed house with a small inground pool that is surrounded by a sunroom. When I bought the house, the pool water was black/brown/green. I have since followed advice on this site, and for probably less than $50 or so, I now have the pool water crystal clear. I was also having issues with the pump pressure..was around 28. What wonders a new filter can do!! I had kept the old filter (cartridge) while I got the water to a certain clarity point so that I did not subject the new filter to all that crap. Once I installed the new filter, viola, pressurre now hovers around 18. Here is my next new problem. The pool has a heater. All the pool equipment (filter, pump, heater) is in the basement of my house. I turned the heater on, and it seems to work fine. I set a temp and it was slowly raising the temp of the water. However, I noticed it was getting kinda "steamy" in the basement while running the heater. The heater has a vent that comes out of the heater, goes through the basement crawlspace to a vent that leads outside. There is also what appears to be a kind of mini fan that I think blows this exhaust outside once it reaches this point. I checked outside, and could see that air/moisture was definitely being vented outside. The crawl space was really steamy. Here is the question, how do I know if the heater is vented correctly? Natural gas scares the hell out of me and I am afraid it may not be vented properly. Would it be common for the basement to have this "steamy" effect? I took my Carbon Monoxide detector down there for a few minutes and it did not register anything. Anyone have any ideas or answers? Thanks in advance!