Help with additives.

[JasonJ]

my tank has been up for about 2 months now.
20gal tank
35lbs LR
30lbs LS
AC150
Prism skimmer.
130 watts 24" coralife PC

clean up crew(hermits,snails,fire shrimp)
2 false percs
open brain
2 heads torch coral
2 heads hammer coral
Green star polyps
green hairy mushroom
a frag of zoo
and a really small ricordea.

i do water change every week.
should i still dose with iodine..or is water changes once a week good enough?


and how much calcium should i dose?..kent kalk? or kent luqiud calcium?
im new at this...so please help me.
thanks.