I think it depends how often u feed ur lifestock lah, less feeding = less shit = less diatom mah. Your skimmer is also the determining factor as to how much more fishes or corals u should add.
For those of u who have been smsing or have the intention to, i bought the Tunze skimmer for $320 and only used it for 4 days. Pls dont expect me to sell u an almost brand new German made skimmer for below $200. Sorry no offence ...