Tap @7.2 is fine, EJ doesn't seem to play all that well with RO water. You will need to bubble the chlorine out of the tap or let it sit out for 24hrs. RO is great for hydro, less so for soil and even more less so for organics. This has just been my observation over time.
First your soil. Most organic or peat based mixes are acidic and need something to buffer the soil's pH. I use powdered dolomite lime. DON'T mess with the pellets as they take waaaay too long to break down and work. Oyster shell flour is also good if it's available. Lowes is the only place around me that has the powdered/ground dolomite lime.
Besides buffering your soil and keeping the pH in the sweet spot, dolomite also provides cal/mag and keeps those problems from popping up.
"I" use 1tbl/gallon of mix or 1cup/CuFt of mix. Works best if added to the mix before use, but it can be top dressed on and watered in. If you are going to transplant, be sure and add it to the mix.
Now the Earth Juice.
First off, it's best not to think of EJ as a nute like FF or something where you just mix it up and dump it on the plant. Think of it more as a nutrient tea and you are closer to the mark.
It works best if bubbled. A cheap aquarium pump, airstone and a 5 gallon bucket will get you going.
Catalyst is very important!!! This is the 'food' that gets all the microbes and BB in the EJ woke up and ready to work. Molasses will also do since it is cheaper than the catalyst, but the cat has more goodies in it. I usually alternate between the two of them or, use 1/2 doses of each.
Micro Blast is also very important. Most organics are very light on micros and trace elements and the MB helps prevent deficiency's. Don't need a lot or very often, but you do need it.
Meta K - K is very important in flower and this is good to have. Myself, I've gotten away from the MK and now just use ProTekt from Dyna-Gro as both a K source and a silica supplement. It works great at both and cheap to boot.
Any questions, ask away.
Chems are a lot easier aren't they?
Wet