Your doing great. Be careful of the hydro store... There is a lot of overpriced stuff there designed to make it seem complicated and a mystery bottle to cure everything... I believe you chose the best and easiest medium to grow in. Coco is not hard to grow in imho...
Coco, Low concentration of Nutes, Fed as often as you can/want in a breathable pot is a recipe for success with little to no nute problems... I've had little to no real nute issues since going to that mantra... I beleive many nute problems are from the over-nuting that the nute companies push us to do...
You don't need to go crazy with nutes and spending oodles... They are overpriced for marketing sake... "It's expensive so it must be exquisite and excellent". The reason there are so many bottles is these companies "forget" to include the micronutrients in their base nutrients.... Lots of us coco guys just use Jacks Hydroponic dry nutes or similar... Two parts, three if you add Epsom salt now and again... Highly effective, simple to use and costs pennies on the dollar of Hydro store nute brands... Only thing I buy at the hydro store is coco and light bulbs...
