Is the mixture bubbled? Mate ive left a plant in the same res for 2 weeks before and there was no harm done- but it had an airstone in it.
If it was organic it would be a def no. But synthetic- might be ok just check ph again
No bubbles in there Sanga, it's just a water butt with a battery powered timer. It's in the dark, and cool.
The pH went from 6.5 to 7 over a week and a half.. The plants are drinking it now so I suppose I'll find out soon! [emoji38]