Can’t decide on what what parameters to test for or what test kits are the most reliable? To determine the types of tests you need to perform will depend on the type of aquarium you run, as well as what stage the aquarium is in. If you run a fish-only system, things like calcium and alkalinity may not be of any use. Also, if your aquarium has been up and running for a few years, then test kits for ammonia and nitrite may be pointless. On the flip side, if you are just starting a new aquarium, test kits measuring ammonia and nitrite are crucial, as they will help you determine if the aquarium is still cycling. As for the types of test kits, there are two different kinds…titration-based and digital. The titration test kits are easy to use and are inexpensive. Unfortunately, they can be very subjective (e.g. color changes) and do not offer the resolution of digital testers. The digital test kits are a bit pricier, but are also pretty easy to use and can read results down to 0.00 ppm, usually. Both choices are good for aquarium keepers, but the choice usually comes down to ballpark figures versus better resolution.