well your next option would be to add some ferts. Are you just dosing flourish then and not excel. If so get some flourish excel to get some co2 inside unless you want to go pressurized (IMHO its the best since i finaly gave in and got it) also you need to get some macros and micros in it. Look over EI dosing methods from dry ferts or there are some vendors here that are selling liquid ferts already mixed.