Hey Autobud mate, been around but not long enough to make comment.... buds looking good though Bro, glad you got some decent lighting... just in time, cos now's when they need it!
Keep the MH ready though, some like to use MH in the last 2 weeks to boost trichs.
RO water is also known as Reverse Osmosis water.
Basically tap water has all sorts of stuff in it, Chlorine, Fluoride, trace minerals etc. If you measure the EC of tap water, it may range from EC 0.2 anything up to 0.7 and beyond. EC is the Electrical Conductivity - or another way of saying there's stuff in it. Pure water is EC 0.
When you grow with nutes, you want to have complete control over the EC, and if you want to have EC 1.0 nutes in your feed, and the EC of the base water is already 0.5, you're effectively gonna only be able to add EC 0.5 of your nutes to make a final EC of 1.0.
On top of that the mineral content of your tap water may vary, so you just don't know really how much Nitrogen (N) Phosphorus (P) and Potassium (K) you have n your nute..... and you need N for veg and P and K for bloom.
Reverse Osmosis is a way of purifying tapwater, its basically a series of filters that removes everything from the water. A RO machine is a simple filter that attaches to your water supply and gives you pure EC 0 water, which you can then add your nutes to.
They look a lot more complicated than they are. I used to have one screwed to a panel of wood, and just rigged it upto the shower hose. Took about 2 hours to make 60L of pure EC water in one of those flexitank things.
I then let it rest for 24 hours then bubble air through it for 24 hours. This gets the oxygen up - great for the roots. I just used a cheap aquarium water pump with a few feet of hose on the end. To get air into you water, you can use an
air pump with an airstone, but I used the
water pump and hose to pump water out of the res and have it pour back into the res again.... the air gets into as it splashes away - fluming, I think it's called. The water pump and hose is also great for moving quantities of water from one vessel to another quick time. I keep it running in the res while adding nutes etc so it mixes it all up.
1st thing to add is Cal Mag to bring the EC upto 0.2. This helps buffer your water (protect it from wild pH changes)
Then I add the A and B as per the manufactures recomendations, I usually split the res into 2, and add A to one, and B to the other, then mix the 2 back together.
Then I let rest, check and adjust pH, rest again, then add the extras.
You have to read Autoberrys stuff, he is a mine of information, you have much to learn from him.
Must run, speak soon.