i have about 12 small cactus no bigger then a foot and some of them look like they are being affected by the fertilizer im usaing. im using a 2 7 7 cactus fertilizer supposed to be for all cactus and succulents i only fertilze once a month the directions say for indoor cactus 7 drops for every quart of water i do about 5 now after about a year of fertilizing 3 of the cactus look like they are growing retartidly should i stop fertilizing them