Hi, I have zinc buckets in the stand from IS, we have had them for 3 years now. we do not use any flowerfood as it will react with the buckets, we just change our water regularly and bleach the buckets regulary and have had no problems with flower life at all, we do turn our flowers over very regulary and this all seems to work. we never put cala lilies in the metal buckets tho because the stems go mushy!!!!