Main reason I guess most sites point to 30c is cause of digestive related issues - which does make sense I feel... for now..
Not really, at low temperature metabolism is low so they need less food. At high temperatures metabolism is high and need more food. But in both cases they need easily digestible balanced food.
Fyi, hikari recommends bio gold plus over gold.
Which Hikari diet should I use for my Flowerhorn cichlids? - Hikari Sales USA
We recommend Cichlid Bio-Gold+ for Flowerhorn cichlids. You can also try Cichlid Gold & Sinking Cichlid Gold as economical Flowerhorn feeding options.
www.hikariusa.com