I have 4 Northern light plants that are 4 weeks old. some of the bottom leaves are turning a shade yellow. I have 3 of them in Miricale grow soil with 40% perlite. Its the soil with the 3 month nutes and I have one in Foxfarm Ocean Forest with 40% perlite. I was wondering how much fish emulsion I should give them per gallon. On the bottle it says it will not burn them. The plants are not ver big yet. light 6 or 8 inches.Thanks