RoguePlant, I highly recommend picking up Botanicare's hydro nutes. It's a much cheaper line than the FoxFarm or Advanced Nutrients stuff. The results are absolutely fantastic, too. It's a great formula, I have nothing but good things to say about it. I picked up a gallon of Botanicare 3-2-4 for about $30 and I only have to use a quarter cup of it when replacing the nute solution in 5 gallon DWC buckets.
It's one of the biggest things you need to get past when learning to grow. Most products on the shelves are a complete ripoff, marketed with absolutely absurd technobabble (I really don't know how anyone can take it seriously). And a lot of "secret tips" for growing are bullshit, too. All you have to do is keep the plant as healthy as possible, and then dry the buds as slow as possible without molding them. Everything else just wastes time, money, and adds complexity.
Those "Clearex" solutions are the worst I've seen. It tickts me off seeing that sold for $20 per liter when it says right on the lab that it's nothing but water and a spoonful of SUGAR! Again... marketing... growers are flush with cash and suckers, they're always stoned off their asses in the shop...
Again, I do use RO water, I think it's always a good idea to do so because then you don't have to worry about the amount of dissolved salts changing with the seasons (such as snow melt/runoff in the spring), or corroding pipes suddenly unloading a bunch of copper into the water. If the salts have been removed, you just need to add a bit of CalMag as well, and then you get completely consistent results.
From my experience, 5.8 is the ideal pH both for rooting and growing plants hydroponically, so it sounds like you've managed to stay right on target.