Help with Alkalinity

[EasternRomioi3]

Hey guys, I just got my axolotl's tank water tested, all her numbers are good except alkalinity, which is 0. The chart the pet store gave me says the ideal range is 120-300 but I have no idea what measurements, units of measurements that is. Does anyone know? All the pet stores around me are out of alkalinity buffer. I ordered some off Amazon. Is it safe to use while she's in the tank or do I need to remove her? I am in a massive hurry because I'm going to be late to work but she's important to me. Please help.

Here are her levels.
pH - 6.2 (I read 6.5-7.5 is needed, they said the low alkalinity will bring the pH down)
chlorine - 0
ammonia - 0
nitrite - 0
nitrate - 40 (axolotls need 20-60, I read multiple times. This correct?)
hardness - 300 (I heard that 300 to 350 is ideal, is this true?)
Alkalinity - 0 (their stupid paperwork says ideal range is 120-300 but they said they have no idea what an axolotl even is, let alone what it needs).

Please help, I'm trying to do this from my phone at work and I'm stuck on cash register all day. My axolotl ate her breakfast, isn't lethargic at all, not aggressive, but it's 100 degrees out today and I've had to put my treated water into the fridge because it was already over 80 degrees and we have no AC. I don't want her getting sick! I've been up since 2am sobbing over this waiting for the stores to open. Can anyone help?

 

[Calgarycoppers]

That pH is crazy low - botanicals bring it down as well - What is your tap water pH ?

Nitrates can cause issues from 40 and up so we try to keep it at 20 or below - 40 triggers a water change. 60 I would do a 2/3 water change.

Alkalinity - Add crush oyster or coral in a nylon in the filter or use holtfreter solution.
Hardness - will increase with the alkalinity treatment

 

[EasternRomioi3]

I was able to get some alkalinity increasing stuff and some pH increasing stuff from the local aquarium store. I did 3 separate readings, before, after, and much after, her water scored a 7.0. She ate dinner tonight and very curious with us messing with her tank. I haven't seen any slime or anything on her gills since I left for work this morning. Could it just be something from her sleeping? She's usually asleep when I get to her in the morning.

I'm gonna leave her water be for a bit and change it maybe on Tuesday or Wednesday, just a little, and keep testing. Am I doing the right thing? She seems fine, I was just alarmed at first when I saw it and now it's not there and she's being her usual self. She's actually be much friendlier since I got her tank cooled down, she comes out to greet me when I come to the end of her tank, she ignores other humans, so clearly she knows I'm beneficial to her, at least for food.