Minerals are what buffer/change pH. The more minerals you strip out, the less stable the pH will be.

I personally just use the input fan straight onto the plants, either as an airshower from the top onto the canopy, mine is overpowered and strong enough to do so.

I’m thinking of using a length of ducting with evenly spaced equal sized holes, or possibly a piece of plastic drainage pipe with holes drilled in it for air distribution.

I use a filter on incoming air if I have a male in next room or he bangs every thing filter works for me

I have a 4” duct from my AC vent straight into the tent…. I’m planning on adding an air box filter and a helper inline fan to help with any dust particles…. This is my first go ever at this

All my intake passes thru an acifinity carbon filter and cloudline fan…8 inch fo my 4×8…I use inline fans with carbon filter for the 4x4s and 2×4 tents

Yes. I use a small vornado for pulling air in through a bottom vent sleeve it fits perfectly. I use an AC Infinity to exhaust which I have outside of the tent on top. It gives maximum space. My only other suggestion is a clip fan for air movement.