Cleaning and preping a used tank for saltwater

Question
QUESTION: HI,
I just bought a used 30 gallon aqaurium that I plan on keeping a few saltwater fish in.  I have not yet tested it for leaks but do plan to in the next day or so.  I have two questions.  First, about an inch or inch and a half fromt he botton there is a brown ring of dried scum (algae?) and sprinkled intermediatly arounf the class there are also many calcium deposits.  What is the best way to clean these off so the tank will be safe for the fish.  Second question, If I do find leaks in the tank do I need to remove the old sealant before applying new? Thanks for yor help.

ANSWER: Hey Jerry,
A little vinegar will remove almost anything safely from aquariums(MUST BE RINSED THOROUGHLY AFTERWARDS). You can even turn it on its sides and allow the vinegar to soak for an hour or so to make cleaning even easier. Works great on old algae and hard water deposits.
And no, you dont have to remove the old sealant as long as its not torn or gouged enough to interfere with the new sealant(remember aquarium grade silicone only and a minimum of 32 hours to cure before filling for fish).
Hope this helps... let me know how it goes or if you need anything else!

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QUESTION: I don't plan on having fish in it for at least two months so the curing time will not be a problem.  My next questions are:  First I plan on using live rock and sand along with a protien skimmer and an aquatech 30=60 gallon filter.  Do I need to use the activated carbon pads with the filter in the salt water tank? Second question (jumping a bit ahead)  The tank will eventually house 2 clownfish (of the 'nemo' varity)  A couple of skunk shrimp and a turbo snail to begin with.  Will a Yellow tang also work int his tank?  I know it gets to be 10 inches or so but if I put him in their I would not add but maybe one or two 2-3 in fish with it (we are thinking of Pajama cardinal fish).  thanks again!

Answer
Hey Jerry,
I run activated carbon in all my systems. It really helps with water quality and clarity. I change the carbon stockings every 3 months(yes, I use nylon stockings for carbon, they hold more, are cheaper and have great water flow). The Yellow Tang will do ok in the 30 gallon for 2 maybe 3 years, they do like room to move so it will not be a very active Tang and become less so as it grows. Ideally a 55 gallon is the smallest I would use for any of the Tangs(Maybe you could upgrade in a year or 2?). I definitely wouldnt add more than 2 more SMALL fish(1.5 to 2 inches at the most), gobies, cardinals, damsels etc. I would also make sure you have above average water movement(powerheads and filtration) just to make sure he gets pristine water quality and the "sense" of movement can really help fish(behaviors/personality) in smaller systems. Good luck. Let me know how it goes.