In the weekly tracking of our tanks' trace elements through ICP analysis, we've found some interesting results and subsequently, come up with some interesting suppositions regarding what we think is happening to cause these results. One of the most interesting, however, has been what has been occurring with the iron levels, and we wanted to share it with you.
Some Iron Background
Just as it is with human beings and other mammals, iron is also an important nutrient in coral growth and coloring. If you think about when a person is iron deficient, they are often more sluggish and tired, they sometimes can have damaged hair and skin, and can become pale. In corals, iron plays a similar role, giving energy to grow and to provide coloring, especially greens. So this is a pretty important element to have in your system to maintain a healthy coral environment.
However, just as we talked about in our previous post about iodine, not only can iron detection be tricky, but too much of it in the system can be toxic to your aquarium. Again, similar to iodine, iron will switch between different forms, but instead of only three forms, iron will switch between seven. The form taken will depend on salinity, pH, alkalinity, and the amount of organics in the water, and not all forms can be measured by a typical aquarist grade test kit. Furthermore, the normal level of iron in seawater is around .0005ppm, below the detection level of many of these test kits.
With our ICP analysis, we can detect these levels of iron that would normally be out of the range of detection for many iron test kits, and have been doing so. At first, many of the tests indicated that the iron levels were at 0. Knowing how important iron is in providing energy for corals, we decided to dose using Red Sea's Trace Colors C supplement. But an interesting thing happened, within 24 hours, the iron levels kept reading 0. So we dosed more. Very carefully, we increased the dosage based on the ICP analysis results until we reached consistency with the iron levels.
This led our owner to wonder why the iron levels were so low, but even more, why they dropped so quickly after dosing. Though there may be other factors in play, such as precipitation or changing iron forms, through research (much of which was provided by Red Sea directly), he came to the conclusion that the corals were potentially iron deficient and absorbed the iron quickly. So as he dosed more and more, the corals were absorbing the iron they were in need of until they reached the point where they didn't need any more.
The tanks have been measuring at a consistent level of iron for a couple weeks now and the corals have looked great. The dosing for iron has continued, but at much lower amounts to keep the tanks stable and consistent. But this kind of discovery with our tanks wouldn't have been possible without regular monitoring with ICP analysis. Is this to say our corals would have been in danger without the testing? Probably not. Regular water changes still provide enough nutrients to live off of, iron included. But we have been able to maximize our results with the testing and provide the absolute best environment for them to thrive. Without this regular testing, we wouldn't have known to increase our dosing or when the iron levels had stabilized and we could decrease our dosing.
If you're interested in ICP analysis for your aquarium at home, they are available here as a single test, 2-pack test, or 4-pack test.
If you need an iron supplement for your tank, there are many available with Brightwell, Seachem, or others. We often like to use Red Sea, and therefore for our iron dosing, we used Red Sea's Trace Colors C.