in short yes...but you need to test for calcium. you really dont want to be adding for the sake of adding.testing for cal can be a bit of a pain ...but it IS needed especialy when dealing w/clams+sps/lps corals. alk is just as important. you really should test this also. this is a much easier test to take. I use the "Fast test" kit.
For calcium I would recomend "Seachem" "Reef Advantage Calcium"
For alkalinity I would suggest "Seachem" "Reef Builder"
these 2 products are a powder instead of liquid and I believe they are a good cost effective way of keeping up w/alkalinity and calcium if you do not have the high tech equipment. I run a bare bones tank and this is really the only 2 things I add 2 my tank.(as long as good husbandry i.e. water changes are met).
Again I want to stress testing b4 adding.too much of a good thing is not good...lol.
oh...and p.s..these additives CANNOT be added at the same time. There is a chemical reason why which I`m not all that clear of myself but you need to add them some time apart. preferable 24 hours.
And not to confuse the matter but alkalinity is measured 2 ways so make sure u understand the test kit u buy . Some measure in whats refered to as meq/l and some are measured in dkh. the difference is kinda like the U>S> method vs the metric method. example:1 meq/l=2.8 dkh. so 2 meq/l=5.6 dkh. ideal for clams and reef in a tank would be 3-5 meq/l OR 8.4-12 dkh.

Phewwwww...thats about as complex as I get. lol...hopefully Casey will be along to mabey make this more simple.