Here;s the response.Well here's their response.
We would always recommend using the marine test kit, as they are buffered and calibrated differently to the freshwater test kit, although the results will be similar, so should give you enough of an idea as to the quality of your water. I would highly recommend purchasing a Marine Lab multi test kit so you can be sure of the parameters.
So here's the thing. I have tested the saltwater I collected and have in my tank to make live rock. The Ammonia coloration comes up as being bright blue on their chart, the nitrate and nitrite are so marginally coloured as to be neutral.
I wondered if the high ammonia level was because of the rocks that had been put in the tank so I went back to the coast and got a fresh sample of seawater. It tested only slightly better for ammonia, still at a lighter blue and the nitrate/nitrite levels are the same the same.
I can't believe that fresh seawater would have ammonia in it so there seems to be some merit on what NT Labs say.
I still find it obfuscative of them to not go into actual comparisons with a direct relationship, one to the other.
I'll try again.
However I'm not sure if I need an extra kit. The cost is high when I'm stocking with marine stuff.
Are there really any differences between the freshwater and marine kits. I mean ACTUAL chemical make-up or strength. I'm not interested in what the chemical constituents are, just whether there's any real difference.
I'm being especially careful in both directions, i.e. cost and safety.
Most of the reagents are formulated and calibrated differently between marine and freshwater, you’re going to get the correct results using the ammonia and nitrate from the freshwater, however the pH results will be incorrect, as the freshwater reagent is not formulated to test for marine parameters, and the KH and GH test you get with the freshwater are not applicable for marine aquariums, you don’t need to test the GH of a marine take, and the formulation of the KH reagents is also different, as the required results are very different
What do you make of this?