Reclusion

Heading onwards from Borjomi, we arrive at Sascha's next possible soaking site,

Vardzia. Sascha:

'The village of Vardzia is definitively not famous for it's hot springs, but for the caves that gave home of 50 000 persons in the past. 

In the rocks, there is even a (cold) spring that fed the troglodyte city with water.

It is an interesting place to see, the 60 km from the main road (from [the town of] Akhaltsikhe) are worth it, even if it is 100% touristic. There is no real town, just some guesthouses and a good 4 star hotel, that I definitively recommend, in particular after (and before) nights in simple guesthouses or camping'. 

Virtually all internet information available on Vardzia concerns the cave dwellings which are indeed impressive.

But, the hot springs? Sascha:

'Most tourists who come by tour operators do not know that very close to the caves, there is a hot spring in a ramshackle that is really not bad. 

Cross the river like you want to go to the caves. Do not turn right to the caves but to the left. Continue the street for about 1 km. On your left hand side are ruins and a sort of geyser (see picture). 

Take the little street to go down to the geyser and after a few meters, you will find the house with the thermal pool. If you don’t mind the littering around the geyser, enjoy for a natural massage, the water should be around 44°C at source. 

According to comments in the internet, the hot spring was discovered when the government was on the search for oil. Since then, the area was more or less abandoned'.

 

But there's more than just this. Sascha:

'What is more interesting is enjoying the pool in the house. 

If no other visitors are there, the house will probably be closed. 

First option is to ask locals to contact the guy with the key but not everybody seems to know the hot springs. 

Second option is to find a local who calls the hot springs owner. His name is Mamuka and his number is 59844089. He will open you the house, wants 5 Lari per person and plays on his mobile in his car outside until you are finished. 

It doesn´t look very beautiful, but it was a nice experience. The water is around 44°C hot with no sulphur smell but is very salty. The pool is quite deep so a real soak with several persons is possible. Swimsuit seems to be optional'.

Chacha

I tried looking up more info on the net concerning soaking experiences here. There are though very few recent accounts. For instance on instagram there are thousands of photo's #Vardzia with very few actually concerning the soaking possibilities.

Tripadvisor rates a visit to Vardzia with the maximum 5 stars, though this does not reflect the soaking experience, solely a visit to the cave dwellings.

The most factoral account is to be found on thermalsprings.ru (2017). Translated from Russian:

'Location: The well with hot water is close to the river bed, 1 km to the west of the road junction at Vardzia fortress.
Infrastructure : a well, a swimming pool in the building.
Description : well pipe coming out of the ground at the level of about 2 m, a well of flowing. It is said that the Coca-Cola Company gets out of the water for its carbon dioxide production. Nearby, close to the river channel, among several buildings of uncertain purpose, local entrepreneur built a small building with a swimming pool measuring 6 m to 3 m. The pool is always open (in the words of the entrepreneur, who was at the pool during the visit to the source).
Type of water : pH = 7,19, silnosolonovataya M = 8.8 g / l, T = 39.3 ° C. Carbonic'. 

The extensive website also has some good photo's.

Georgeous (2012) looks beyond the pH's and more at the experience:

'Joining the locals and the polish couples was the best we did since they offered us food and booze. ;) they were all very nice and after a couple toasts of chacha (a very strong georgian liquor), georgian cognac and some polish vodka the locals asked us all if we fancied going for a swim at theirs hot water swimming pool.
At first I found it very strange but then the polish explained that that area was known for having hot springs - basically those are pools with heated water that comes straight from the underground at a temperature around 35 degrees. Why not? was my thought and we all went. The pool was in a falling apart warehouse but we only got to figure that out on the next day.
However, I have to say that it felt really good to go in a Hot Spring at 1am. Not too far away from here, there was also a kind of a jet stream of the same heated and salty water where we had a really nice shower on the next day. It was the perfect place to take really cool pictures!'

steveandjustyna (2014):

'There is a crude little "swimming pool" and a sheet metal shed built around the hot spring. The water "flows" through the pool; it enters on one side and exits on the other. Then the water flows down to the Kura river, which is nearby (approximately 20 yards away)'.

Another experience can be found with hamstersha (2016) with some photo's. 

Batumilife adds (translated):

'Hot Springs For 100 meters from the entrance to the cave complex there will be a fork and a road sign on which "Upper Vardzia" is written. Turning on it to the left, after 300 meters you will feel a not very pleasant sulfuric smell, which comes from an incomprehensible pipe. This is one of the hot springs in Georgia.Unfortunately, it is abandoned and not ennobled, but you will not be able to kick your feet in it, and for those who want to swim there are old pools with this useful water. True, what would get in them, you need to call the owner on the phone written in huge numbers right on the wall of this building'.

Charming

But the Vardzia area has more on offer. Like Vardzia, Tmogvi (or T'Mogvi) has no apparent fame for soaking, rather it's visited for a visit of ruins of a former fortress.

Sascha though on the hot springs of Tmogvi: 

'Some kilometers before arriving to Vardzia, a little town called “Tmogvi” has also a hot spring pool to offer.
The owners also run a guesthouse. If you stay in the guesthouse, the pool is for free, otherwise a small fee needs to be paid.
The pool is not natural and part of the house on the groundfloor. No charm, no windows, not really interesting for me'.

Probably Sascha refers to the Imedi guesthouse. Booking.com:

'Boasting barbecue facilities, Guest house Imedi is set in Vardzia. Among the various facilities are a garden, a terrace, as well as a shared lounge. The guest house features a hot spring bath and a shared kitchen'.

Reviewers on the booking site reward a stay with an 8.7, though there's no reference to enjoying the soaking possibilities. 

thdk.be did test the waters:

'We spend the night in a family run guesthouse in Tmogvi. You could also call this place a thermal farm. A water installation drills deep in the ground and gets hot water several baths owned by the owners of the guesthouse.
No wonder so many people were around the house last night. It’s a wellness center!
Before we took our morning bath, I made some pictures of the main house and the bathhouses'.