one inexpensive tool that I have found to be indispensable is a soil test kit like this one
http://www.ebay.com/itm/380551813848?_trksid=p2059210.m2749.l2649&ssPageName=STRK:MEBIDX:IT different strains have different needs and it can be hard for a new grower to "read the plant" to determine the cause of problems.without a PH meter ans soil test kit you are really only guessing why the plant is unhealthy and how much feed it needs.it could be easy for an inexperianced grower to mistake a phosphorus deficiency for excess nitrogen or high (or low) PH with a pH meter and soil test kit you know your plant is getting what it needs. I have found that organic soil like Kellogg patio plus and organic fertilizers from home depot or lowes work just as well as the expensive stuff from the hydro store and the list of ingredient is often the same.having well drained soil is also very important. this can be accomplished by adding perlite to your potting mix.25% works well for me. good luck and be patient. growing is an art that takes time to learn.and welcome to the club