i believe flushing is using like purified water, something with a good ph, definately dont run water straight from the sink into the pot.. as far as the yellowing leaves and the fact that u have so little leaves i had the same problem untill i bought some fish emulsion.. which is an organic fert os it shouldnt burn unless you use entirely too much, it has a 5-1-1 and should help your growth pick up, but flush before you use it.. thats my two cents, but dont go about doing anything too fast, pics and more advice wouldnt hurt so just wait for replies