Very high alkalinity levels!

[Hunter90 HD]

Definitely your source water. I was using well water and it mixed up at 26-28 dkh. Now I use RODI water and that keeps it at 9.5-10.5 with instant ocean reef mix.

It was my source water

 

[Rmckoy]

Should be around 7.5 but I am just running a new batch of fresh RO water and will test the alkalinity before and after adding the salt.
I will source another test kit I think, don’t know anyone who could test this for me to confirm, unless the aquarium shop down the road can test it for me to clarify my testing equipment

If they sell livestock and have tanks they will be able to test it for you .
Most fish stores are able to ......