is there any nutrient or additive i can use in flowering to make my yeild bigger?

i heard superthrive is good?

i have hard water and am using very little nutrients now to compensate the high ppm....

i am using optimum hydroponix a + b flowering nutes for hydroponics. i add epsom salts and a bit of hygrozyme also.


something that would work for both earth and hydro would be best, thanks!