My nitrate levels are acceptable, and nitrite which is toxic to fish and a direct derivative of Amina all show that my bacteria and filter are doing their job!
Just to put this out there - the Nitrogen Cycle goes:
Ammonia to Nitrite to Nitrate ( and then to Nitrogen Gas)
"This conversion from ammonia to nitrite to nitrate to nitrogen gas is known as the nitrogen cycle."*
What the others are saying is that your test showing almost no Nitrites and literally 0 Nitrates indicates that your tank's cycle is incomplete - meaning that the Ammonia (which was not tested for either directly or even really indirectly here) appears to be staying as Ammonia rather than converting to Nitrites then Nitrates (at least according to your test strips there).
In other words, your levels on that test are showing that your bacteria and filter are
not doing their job. (Personally, since you used live rock and TurboStart, I doubt this is really the case - I'm assuming that the bacteria and filter are doing their job and that your fish died from disease, which is why running the tank fishless [fallow] for 60+ days has been suggested; as mentioned, however, having some testing done to confirm this is a good idea.)
Also, freshwater and saltwater tanks are different environments and have different parameter needs/issues. For example, Nitrite (which is toxic in freshwater) is non-toxic in marine environments (like a saltwater reef-tank) at pretty much any level below a ridiculously high one:
In a not fully cycled system, nitrite might possible get high enough to be an issue and I wouldn't put in fish at 10+ ppm nitrite. The lowest tox level I've seen reported for rapid toxicity of nitrite to fish >100 ppm. The 10 ppm gives a protective buffer.
Nitrite and the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com
Generally, the following are good parameter guidelines for saltwater aquariums (the only important one from table 2 as far as most people are concerned is Nitrate):
Randy Holmes-Farley said:
Table 1. Parameters critical to control in reef aquaria.
Table 2. Other parameters in reef aquaria that aquarists may want to control.
In short, double-check that your tank is
actually cycled (and cycle it if needed), and - if it is cycled (or even if it's not) - assume that disease is what actually killed your fish and prep to monitor/QT/treat your future fish as needed to prevent further deaths.
[note: edited on 5/29/2022 to update the nitrate and phosphate sections with higher recommended levels.] One of the main roles of an aquarist with a coral reef aquarium is to ensure that the conditions are right for their tank inhabitants. There are many different attributes of the aquarium...
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*Source:
Florida Department of Agriculture & Consumer Services
www.fdacs.gov