Carbon dioxide injection increases growth rates… for the record dont even look it up yet lol. Its not cheap to do because of all the other equipment you need on top of it to do properly.What is a CO2 injection? And what kind of water do you use for hydroponics? Where is a good place to buy water? It sounds like you go through alot of water.
Water depends where ya live. If you can link a water report i can break it down and see if it’s suitable… if not I recommend a cheap RO unit for like $70 just to get started.
You can build your own system for a very reasonable cost the less grow sites the cheaper and easier.
If you did a 1 plant RDWC you could probably do it in about an hr for $100 2 site about $150