I happened to be having an issue with one (of 8 then) tanks, and consulted my online marine biologist friend (we were both members of another forum at that time). She obviously asked many questions in order to assess the issue, and when it came to Equilibrium she asked me point blank if I really though this beneficial to the soft water fish I had? I couldn't truthfully say yes, so she said, then why are you subjecting the fish to all this stuff? I have never used it since. And the tabs did the job re the plants so even better.
I know next to nothing about axolotl physiology so I will not guess as to whether substances in the water would have more or less detriment than with fish. However, if you want to increase the GH for the axolotl (or fish), Equilibrium is not the answer as it is made for plants and according to Seachem not as good if GH is needed for livestock. They make another product intended for livestock, can't remember the name off hand. There are other products too, like rift lake cichlid salts, that add the necessary minerals to increase GH for fish. Limit the amount you use, and I assume you can work out how much is needed for 8 dH, and for each water change. A calcareous sand substrate would also increase GH (nd KH and pH) but that is not controlled so better if it can be as hard as it gets. I used this for my mollies many years ago.
