I think Seachem is good for basic (PH, Ammonia, Nitrite, and Nitrate). If you have corals, you need to buy Selifert Test kit (KH, CAL). I usually buy them online, they are pretty cheaper than LFS. www.Mainedepot.com, www.premiumaquatics.com.....
i ran out of alk and cal need to buy new ones. just got the marine depot 2006 catalog they have a calcium momitor for $250.00 thinking of getting one..
that calcium monitor was reviewed by RHD at RC in advanced aquarist article and found it to be very unreliable, especially in continous use monitoring, to many molecules that the probe can translate as calcium it says, more complicated then I care to summarize
look for the article before you buy it though, its a good read