Hey bro, I know this threads a year old but I just came across it now. I’m from Oz as well and I’m actually using the same soil you used for this grow. It’s definitely a living organic soil and you shouldn’t need to worry too much about ph really. If anything I think your humidity was a bit low for the size of those plants, I think for the early stages 65-70% RH is easier on them. I also wouldn’t rely on moisture meters too much especially if they’re cheap ones. I noticed on one of your posts you said the light you’re using was new. In that situation I think the best thing to do is follow the manufacturers recommendations until you get a better feel for the light and the plants you’re growing.
But I’m interested in how your grow ended up going. Did things turn around? Were you happy with soil purchase in the end? Like I said I’m using the exact same soil so would be interested to hear your thoughts. That shit ain’t cheap considering it’s just soil (albeit very high quality stuff). The guy who runs OGS is super helpful if you have any questions, I think his name is Jay or something like that.
Peace. Happy growing