My husband and I recenty replaced our 65 gal hot water heater with a 50 gal model thinking this would provide sufficient hot water since there are only 2 of us in the house. However, when I use my jacuzzi tub (a heart shapped model) I find that the water is running warm not hot at the end of the filling process. Is it possible to add a second (15 gal) tank to the existing system?

Is it possible to add a second (15 gal) tank to the existing system?A much better solution would be to locate and repair the present problem.
Your 50 gallon heater should furnish more then enough hot water for two persons. Would this be a gas or electrict heater.
If electric check the elements. For either gas or electric you may have put too much heat on the cold water inlet and melted then plastic flange on the dip tube allowing it to fall.
A dip tube is a plastic tube in your water heater that directs the incoming cold water past the hot water in the upper part of the tank down to the bottom where it will be heated and raise to the top. The dip's located under the cold water inlet on top of the heater. Good luck, Tom

Well, I hate to say it, but you may have shorted yourself on the size of your new heater. I agree with Tom that a fifty gallon should be more than enough for two people, but that's not including filling a large jucuzzi tub. A standard tub, yes. An oversized deep jacuzzi tub, sorry, but no. Some of them tubs can hold upwards of 100 gallons, if not more, so a 50 gallon tank (which works out to actually about 40 gallons of hot water due to cold entering as the hot goes out) just won't get the job done. In a standard home, with standard tub, we will gladly install a fifty, or even a 40 gallon water heater, and never hear of complaints. However, any house with a large/oversized tub, we intall 75 gallon tanks, or better yet a tankless gas water heater. But, since you have already had the cost of installing the fifty, I would suggest installing either another fifty, or even a 40 or 30 gallon tank.

Now, all that being said, (and Im only assuming your tub is large) I would listen to Tom. Here's a quick test to see if the water heater is doing its job to full capacity. Simply take a five gallon bucket, put it in the tub and start filling it with hot water only. You should get about thirty five gallons of hot, hot water, then it will start to cool slightly. At fourtly gallons, it should still be warm, but it won't be hot. At forty five gallons, it may be luke warm, but closer to cold. And at fifty gallons, you most likely wouldn't be able to tell the difference between the hot and cold, its just going to be cold. If this test turns out the way I suspect, then you simply need another tank, or a larger tank. I wouldn't bother with a 15 gallon, cause that will only give you most likely less than ten gallons of actuall hot, hot water. If you have room, go with another bigger tank, and that way you can take your bath, and still have hot water for dishes, laundry, maybe a shower for the hubby, etc. Good luck, and please do let us know what you decide. Take care.

Hi Jim10,

Since you want to add another water heater, add larger one. Costs only few pennies more for the heater but same for the installation. Now, you will have plenty of hot water for your heart shaped jacuzzi tub. Also, I suggest that you install In-Line heater on your jacuzzi tub plumbing. That way you can stay in the tub for as long as you want and you won't be losing any heat.

Milo