What is your take on Nitrates and Phosphates (which hobbyists test for) and the effect on SPS coral colour?
I ask you specifically, not because of any posts you've made on this thread, but because I have a feeling your professional work is somehow linked...
and I know you know what you are talking about.
How would you ideally run an SPS tank as a hobbyists in terms of levels of PO4 and NO3 you will allow in your tank, and what would you feed the corals and fishes?
Thank you in advance.
Hah!
I am a scientist who works on isotopes and coral biomineralization (Bear in mind, that's not all I work on, only a small part, I'm a paleoclimatologist. By formal education and training, I'm a chemical and biological oceanographer, as well as a climate scientist). In another life, I curated live corals for an aquarium/research institute, and maintained rescue/collection permits for stony corals in the Florida Keys National Marine Sanctuary.
I have been growing stony corals for 15 years, and for the most part, Atlantic/Caribbean species where coloring is set by the natural history of the species or colony.
Atlantic or Pacific, my success was always with simplicity. Kalkwasser or two part, water changes, tons of light and water motion, and very heavy skimming. I took a long hiatus (7 years) for graduate school, and am just now getting back into it.
My philosophy growing corals and my opinions on it were and remain unscientific. I measured nitrate or phosphate on any system I ran in the past, caring about numbers only enough to make sure they weren't batcrap nuts, even when I had access to equipment and techniques better than hobbyist quality kits. I tended to make sure nitrates were below 15 ppm, phosphates below 0.05 ppm. I fed corals heavily, since I had access to a big stock of fresh foods: pureed mix of krill, cyclopeeze, squid mantle, shrimp, artemia nauplii, capelin and clam (IIRC). My situation made big water changes (25-50% total volume) every week viable and really easy.
This is just me personally, another anecdote. I have been guilty of chasing numbers recently, and realize it's kind of silly since I don't really believe in absolutes for captive-grown corals, except for keeping them growing.
I'm also (Deuteranopia) colorblind. So it highlights the subjective nature of claiming certain color characteristics of methods, numbers, foods, etc. Many hobbyists don't realize how far down the rabbit hole of subjective bias, qualitative observation, and anecdote discussing coral coloration really is. You are measuring coral coloration how? etc. Simple fundamentals of quantitation are completely ignored.
Coral coloration is art in more ways than the aesthetic.
I've also known Thales personally and followed his tank for most of those aforementioned 15 years.