Adding a Spa/HT to existing inground

[mhoward1]

Ok seasoned pool people and hopefully a pool designer/engineers, I have a question.

When we built out pool, we sized both the pump and the heater for a spa, hoping to someday add it later. Since then, I have come to the conclusion that the demo work, and down time (plus the cost) probably would not be worth it even though we probably should have done it at the time of the build. Another thing that has changed, is the location of where the attached spa would have been located. We are now thinking that we would like it right off the main deck, which conveniently is actually closer to the pump and heater equipment.

My questions are:
Is there any reason we can't tie into the pump and heater for an above ground unit?

if it is ok, where could I find the shells and/or kits that don't have the pumps and heaters built in. The only ones I have seen so far are the Cedar Tubs that are more than just a free standing unit.

We do have the option to install a stand alone one, but then I would have to get it wired, maintain chemicals in two units, and pay the extra for the pump, filter, chemical manager, and heater when I already have units capable of doing them both.

 

[mas985]

Welcome to the forum!

Seems to be quite a few companies doing inserts:

inground fiberglass spa inserts - Google Search

The biggest issue with spas is the plumbing design and the number jets. If not done properly, the jets are likely to be very week. 6 jets and 2.5" pipes are reasonable. If you go with 8 jets, you may need two pumps (& two plumbing loops) but it depends on the type of jets. Decide on the spa configuration, the number of jets and the type of jet and we can help further. Also, equipment model #s would be useful.

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[mhoward1]

I guess my google-fu is a bit off.

The heater is a Pentair Master Temp 400k BTU Natural Gas, and the pump is a Pentair Superflow VS 230V.

 

[Dirk]

Some things to consider...

Do pool owners close their pools for the winter where you live? If so, then you'll lose the use of your tub for that period of the year. You have to blow out all the water in the plumbing to winterize a pool, so you couldn't use your pump/heater/filter for the tub. I suppose there might be a way to plumb things otherwise, so you could use your spa in winter, but I haven't heard of anyone doing that on this forum.

In order to manage only one body of water, and use your main pool as your tub's "sanitized water reservoir," you have to circulate the tub and pool together each day. That means dumping the hot water back into the pool everyday, and instantly losing all the heat you just paid for. And then reheating the tub every time you want to use it. Which is fine. Many people do that anyway, especially if they use the tub sporadically. But others use their tub several times a day and keep it warm 24/7 and covered to keep in the heat and save on the heating bill. You wouldn't be able to do that.

I've been in in-pool spas and deluxe stand-alone spas. They don't compare. One is a concrete bowl with a flat concrete bench, with bubbly water, and if there aren't too many people in it you might get one jet to dig into the small of your back. The other is a collection of custom comfy fiberglass stations, of different angles and shapes of recline, that surround your body, feet and neck with massaging water goodness. Which are you going to be happier with? Which would a cedar tub more closely resemble? Do you want a luxurious hydromassage session, or just some hot bubbly water to sit in? Are custom fiberglass spas available without heater and pump, that you could connect to yours and get the same experience as a true stand-alone? Including all the bells and whistles and controls? I don't actually know, but I suspect not. That's something to think about, or research.

I'm with you, I get it, I wouldn't want to double my pool care chores either, and it does seem wasteful to buy a second set of gear that you already own. But, for me, anything less than the full custom spa experience just doesn't appeal much...

@cowboycasey, @jseyfert3, what do you guys think? How much trouble is it to maintain a spa separate from (in addition to) a pool?

 

[jseyfert3]

The pool requires more physical work (scooping leaves, vacuuming) that isn't needed for a standalone spa. But the spa requires much more frequent testing and additions than the pool does. This would be a pro in the column of a built-in pool.

I think @Dirk hit on all the big things. I've never been in a comfortable gunite spa (at resorts or hotels). But even though I'm 6'05" so a little tall for the pre-molded seats in our hot tub I find it way more comfortable (with the exception of the seats with neck jets, which even my wife has to slouch to fit under at 5'6"). And some of the newer spas we saw at our local spa store had height adjusting neck jets, so that solves that issue. The recliner is her favorite seat, and I enjoy it though it'd be nice if it was a tad longer. Some spas have his/hers lounge seats, with the his seat being longer for this exact reason. Dang it, now I'm talking myself into a hot tub upgrade...

On the other hand if you want to soak with a bunch of friends and have room to spread out and not touch, an in ground spa is admittedly better for that. 6 people in our spa is doable...but you're gonna be close and a lot of people won't be comfortable with that. There are bigger standalone spas that also solve this issue, though they start getting a lot pricier.

So, use it year round in Wisconsin winters? Yup. Tons of jets if desired? Yup. Comfortable seating? Yup. I've said before if we ever got an in-ground pool I may consider a built-in spa for the spread out and drink/talk with friends, but it would be in addition to a standalone hot tub for winter use, soaking anytime with my wife and I, massage, etc.

I know this is a bit rambling, sorry. Bottom line is yes, a standalone tub is more work, but depending on your needs it's totally worth it IMO, so ask yourself the questions Dirk asked to figure out what's best for you.

 

[mhoward1]

Just a few points of reference
- Being in Southern NC, We don’t really close the pool. We have had yearly December swims

- our use would probably be 2-3 times a month. Maybe once a week in the winter. We might use it more as we have used the pool even more than I thought. (Year 4)

 

[jimmythegreek]

It's cheaper in your region for a standalone spa honestly. Even if you don't close pool you will lose all your heat and have to prep for every hot tub event. A standalone is easy to maintain honestly. It's always ready to go too. Retains heat well, amd the standalone is 10x better overall experience therapeutically. Not to mention a retrofit is likely north of 20k where 10k can get you a Cadillac of hot tubs. Would take a lifetime of 20bucks extra a month in electric to make that difference up. I wouldmt trade my standalone for a built in if you paid me