I need to correct this: Washing Soda will raise BOTH your pH and your TA/Alkalinity and used moderately will work. Washing Soda is exactly the same as pool store's "ph Up!" and similar (expensive) products--Sodium Carbonate (different from Sodium Bicarbonate, and from Borax).

Yes, your TA is low, but your pH is a bit low, too, but still safe at 7.2.

If you were to raise your pH to the "ideal" level of 7.6, you'd see your TA would rise as well. How much is anyone's guess. Remember: Alkalinity level IS a reflection of pH. Using Washing Soda to raise pH will raise TA even more than using just Borax.

But unless you are having troubles keeping pH from dropping, your TA isn't really a big problem. Yes the recommended ranges go everywhere from 100- 120 to 80-130, but in a vinyl pool the REAL determinant is your pH's stability. I've run my pool with no problem with TA as low as 50 and as high as 170 and I don't worry as long as pH remains stable.

With a vinyl pool, the two times you worry about TA is if it's not keeping pH stable or if it's approaching 200ppm AND your calcium hardness level is over 400ppm.
In the first, if the pH keeps rising you probably want to lower TA. If pH keeps dropping, you'll want to raise it.
In the second situation, you risk the water going milky from calcium. It's not dangerous, just ugly. And the quick fix is to lower TA, a lot.

So, if you cannot find Borax, you can safely use Washing Soda as long as you understand it will raise both pH and TA.