What you have there is going to be fairly close to distilled water. IF the reservoir in the ac is plastic, it's good to go. Check the ppm/conductivity. It should be really low. You are going to add calmag plus to replace the naturally present elements the plant needs.

BTW 8.0 pH is not very high, it's on the basic end of the scale. pH below 7 is acid. Very high acid would be like 4.5 or lower, where almost no plants can survive.