Today we’d like to present the interesting marine water tests branded Tropic Marin Expert Testset. 
Articolo disponibile anche in italiano.
This set allows us to monitor 5 different water parameters, at the price of 10 € each as the whole set price is 50 €. It is a very good offer if you need to know these 5 parameters chosen by Tropic Marin.
This set is a combination of the separate tests pH, KH (Alkalinity), Nitrite/Nitrate ad Ammonia.
Let’s start with a quick presentation of the four tests.
pH Test (marine water)
For Tropic Marine the pH should be between 8,0 and 8,5. We’d like to add that usually the pH is higher in the evening, as during the day the carbon dioxide is consumed by photosynthetic organisms; while during night CO2 is produced, lowering the pH.
The Tropic Marin pH test allows us to measure pH values between 7.4 and 9.4, a very wide range that should cover all conditions of any marine tank. We can use this test around 100 times, and it expires 12 months after its opening, this means we could test our water twice a week for a whole year.
This is one of the most straighforward test we ever had the chance to try. After adding 5 ml of tank water in the cuvette (using the syringe) we only need to add 1 drop of the reagent and then compare the water colour with those printed on the sheet (with 0.2 intervals). The resulting colour should be easy to interpret by placing the cuvette on the sheet and looking at it from above. We could read a result with an approximation of maximum 0.2.
Alkalinity test KH (marine water)
The alkalinity level suggested by Tropic Marin for your tank is between 6° and 10° dKH. This test should also last for about a year if used twice per week (around 100 times depending on the alkalinity level, expiring 12 months after opening).
With this test, we can measure any alkalinity degree of our water, after adding the 5 ml of tank water in the cuvette we only need to add the reagent drops to measure it in dKH. Every drop equals to one German degree, we stop adding drops when the water colour turns from green to red.
The colour turn is not very obvious as we see some transition colours. In other tests we have seen more drastic changes. For this reason we suggest you use the higher accuracy scale by adding twice the amount of water (10 ml): in this case every reagent drop will correspond to 0.5 dKH.
Thanks to a useful chart we can then conver the German degree to other scales such as English degrees, French degrees, mg/l, CaCO3 and mval/l CaCO3.
We found this test not very accurate. It gives us results that can be around 1 degree uncertain even in the high sensitivity version. It is not that bad, as a 1 dKH change is not so harmful in our tank, but it looks like Tropic Marin realized the low precision of the test, as they produced a new alkalinity test called Kh/Alcalinity-test professional which has a precision of 0.1 dKH. Unfortunately this is not included in the set.
All the other tests and our comment on page two
