Propane Pool Heater Gas Plumbing Setup- Mastertemp 125


New member
Oct 19, 2020
First post, glad to have this forum as an outlet.

I installed a 4500 gal fiberglass pool and after back and forth debate we opted for a propane heater for the pool. We plan to use it sparingly and from discussing with Pentair's tech dept, the Mastertemp 125 (which we purchased) can on paper heat the pool 25 degrees in 6hrs using 8gal of propane. We live in KY, and use a 14-16mil solar cover. I plumbed in the water side of the heater yesterday and working on the propane side now.

Couple of questions to those more experienced:

1) I have a 100lb (25 gal) tank that I bought for my propane firebowls but not using right now, can I use this tank as a starter tank for the heater? We are space limited and can not bury a tank.

2) Can I buy a second 100lb tank and tee the two together to supply propane for the pool? (filling them is quite easy for me)

3) Any recommendations for a regulator? 14-4 WC with no more than 2" drop (per pentair's notes)

4) Would the regulator change if I upgrade to a larger propane tank?

*** any other recommendations and advice I will gladly take on setup, proper propane plumbing


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LifeTime Supporter
TFP Guide
Jul 3, 2013
Southern OK
Pool Size
Salt Water Generator
SWG Type
CircuPool SJ-40
Welcome to TFP :)

Your going to be hard pressed to find someone over the internet to give you advise on something that could blow up if something went wrong... You may have to hire a pro to get something legal and done right.. propane companies do these all the time and it would be worth it to have it done safely :)


New member
Oct 19, 2020
I appreciate the replies. To update my own thread for people that may stumble across it later:

1) The 100lb tank could be used for the propane bowls and probably the heater for short stint but it has to do with the amount of vapor that the tank can produce in a certain amount of time that requires you to have a larger tank, which is why I am moving to a 120gal tank to try and run both with a cut off valve on each item to cut down the flow if needed. Getting the tank and its reg installed Friday and will update this thread at some point with more info on how long it lasts.

2) Yes again but would still not be enough for long usage.

3) For firebowls, most grill and standard regs you can get from the big box stores will work on 100lb and smaller systems, on the big tanks, you get a regulator installed as part of the propane service. Unfortunately from my research they are not readily available for end users to purchase.

4) As long as the pressure at the item being used is in its allowed range, one regulator from the tank should be adequate.

None of it is rocket science, you need to properly test pressures and check for leaks, other than that it is just plumbing.
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