Your cycle will not necessarily start over when you add new live rock, however you can cause what we know as a mini cycle. Where die off from the rock creates an ammonia spike. Well since the bacteria is not built up for more ammonia it takes a lil bit for the bacteria to colonize and consume the ammonia turning it into nitrite then nitrate. Dry rock skips this process, however it does take some time for dry rock to become live.
As far as testing for fish only your gonna wanna test temp, ph, salinity, ammonia, nitrite, nitrate and probably phosphates. Reef tanks require additional testing including alkalinity, calcium, and magnesium.
29g Mixed Reef, 150w 14k Phoenix MH w/ Moonlights, Reef Octopus BH1000 HOB Skimmer, Ecotech Vortech MP10es, ReefKeeper Lite (Plus), PH Probe, Temp Probe, ATO, Carbon/GFO Reactor.