Would you say it's a safe bet that even Though Mo and Cu are listed as 0.00 it's probably just less than that, otherwise they wouldn't list two random things (of all the other possible things) that just aren't in there, right?
Without the ingredient list I would assume Cu or Mo are not there or are there at an extremely low level that plants may not be able to use. However if it is listed with a non zero number I would assume it is there.
As far as a source of CaCl... Would be be an aquarium specific brand? Or just any CaCl?
No specific brand just look for 99% pure CaCl2. it is a common chemical and is readily available on line. I got mine at loud wolf.com Calcium chloride will increase GH but will not effect KH. I use a GH booster I made from Calcium sulfate, calcium chloride, and magnesium sulfate to insure I have enough Ca, Mg, S, and CL I dose that dry to a about 2 degrees GH and it is perfectly safe.
And I am using RO water.
Cu, Mo, Ca, Cl are all essential and plants will not grow without them. From my own experience with a fertilizer without copper and RO water, plants will not grow. Copper sulfate works well for that. Again look for a pure chemical. You could also add sodium Molybdate for Mo.
However you might want to just try mixing some regular tap water with your RO water. If you have copper pipes in your home and the utility collects surface water or well water that is a good chance that would resolve the copper molybdenum and nickel deficiencies in your fertilizer. Sorry I forgot to mention nickel but the amount of nickel needed is small and many people have plants that do well without it. I am not sure how much tap water you would have to mix with your water to hopefully correct for these issues. You might want to try say 20% tap and see what happens. And if your tap water is hard it might also supply enough calcium and chlorine. A lot of ifs but it might be the easiest solution to the problem.
Cory specifically developed Easy Green to create a one-bottle solution where one didn't exist. The multi-bottle products need specific schedules because the compounds they use to carry the nutrients will interact with and neutralize each other.
To some extent that is true Calcium can react with potassium and phosphate resulting in an insoluble Calcium phosphate. However if you dose a GH booster in excess of plant needs the problem should be minimal. . Also the problem is at its worst in highly concentrated solution in the bottle. Once the nutrients are in the aquarium they are so dilute that the problem is greatly minimized. I have not seen anything in my aquarium indicating that is a problem and I have a very accurate Phosphate meter.
If you have red plants you want to look really red, you could add Easy Iron to the mix
The red color in red plants ins not due to iron. While most iron oxide is red there are many other chemicals and organic molecules that are red even though they don't have iron in them. Also terse are some forms of iron that are black, green, and yellow. In many cases a lack of red color could be due to a nutrient deficiency that is not related to iron.