Do what SB does with the silica.... Give it to them up until they show sex, make sure a mix it in plenty of water first before adding it to your buckets... Ie: lift 4 or 5L of PLAIN bubbled tap water (what ever water your using, RO, tap, distilled) out of your bucket & pour into a separate bucket.... Throw in your desired amount of silica into that seperate bucket... Mix well in the 4-5L & then pour it back into your main feed bucket & then carry on mixing in the rest of your nutes... Simples!! Silica is very alkaline so watch your pH which you'll have to do anyways but the silica will push your pH up.. No doubt.