Im from old school where Kent products were easily obtainable with good success but can achieved the same with other well known brands. Although I have not used Purple Up, heard good thing with
coralline algae from other local hobbyist.
I would not dose the tank until you try out few pcs of corals. No matter how important the additives are, when over used, it is just another pollutants in the water and waste of money as with taking too much/many vitamins for person (actually can be toxic due to overuse/misuse of vitamins). Your salt mix might have enough to handle the few pcs of polyps. Also look into Gorgonian/whip/fans (difficult to find undamaged pcs sometimes) . They are also nice addtions.
If when possible, obtain Cal,
test kit? There are other test kit such as
alkalinity, Fe (iron),
iodine testkits, etc, etc but at least Cal test kits if you dont already have it.
Obtain Coral Book if possible by Eric Boureman (nice book for beginner).
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