Amazing information, after weeks of suffering from poor colors in my corals and many lost corals, K seemed to be the answer. Testing my potassium, with a reading of 320 ppm, I started a dosing regimen to maintain ~400 ppm my colors are back and brighter than ever and many corals that I thought were lost are now growing tissue again. Like you Marc it seems my salt mix was low in potassium. It seems we both learned the importance of potassium in our reef tanks. Thank you for sharing this information.

Great video, interesting discussion, so much great information. Thanks Justin and Marc.

Wow!! Great info...Thanks Marc!

Great video Marc I have used the salifert potassium test kit for a while , definitely recommend it , very easy to use

This was really interesting, I've never heard of this guy but he clearly has some specialized knowledge, I also found an interview you did 11 years ago with him. Thanks for this knowledge transfer!!

This dude is all over

Question: Can you have to much potassium? Heard him say 2 test showed 1200 so how much is too much to really show them colors? How much do you really need for flouresant colors? Time to test with your tank 450 keeps corals alive ,900 might bring out them colors more

Anyone know Justin's channel? it's not in description..

I don’t understand why K has not been emphasized? We’re growing photosynthetic protists, inside of an animal. Yet, most husbandry advice seems to be solely focused on the animal alone, ignoring the protists. My only assumption is that water changes alone has been enough for most reefers to get by, and not have to worry. Coming at this hobby from agriculture; the most important factors for growth are stable pH and three primary elements: N, P, and K. They are critical for the rapid expansion of biomass. C, O, & H are technically the most abundant in living organisms, but those are derived primarily from CO2 and water. And because they are marine Ca is also critical. But, I don’t understand how N, P, and K, were so overlooked or misunderstood for so long in the Marine hobby. When other disciplines have understood their sheer importance for over 300 years of scientific pursuit. I’m also not advocating for intensely eutrophic water conditions. Most oceans are oligotrophic, and reef available forms of N & P seem to be in organic forms, or quickly consumed from nearby animal excretions. So, my comment is meant to be in the context of keeping a reef. I just don’t get how these three elements are so misunderstood by the hobby… But, I would also doubt their is a need to create increased levels of K in solution. Potassium is rarely incorporated into tissues directly, but it's required in every living cell due to how it regulates and maintains electrolyte balances. Elevating it, shouldn't do a whole lot. However, having insufficient Potassium is catastrophic in any animal, plant, or protist. There cells will fail to regulate fluid exchange. So, a hobbyist has to have enough K in solution to satisfy the growth demands of every new cell produced. Or that organisms will become stunted, and then begin to die. This is also true for most micro-nutrients (S, Mg, B, Cl, Fe, Mn, Mo, Ni, Zn, Sr...), a case for elevated levels is barley justified by understanding the organisms biology. However, falling short can do significant damage. First by limiting the amount or type of growth, and at more extreme ends will result in death. The levels required in your fixed volume of water, are all relative to the growth rate of each species in that fixed volume, and is dependent on which form they can access and uptake. The agricultural model which shows this relationship is know as "Liebig's Law of the Minimum", dating back to 1840 in Germany. It's based on plant growth, but is easily adapted to nearly every form of biomass production we persue, so long as you understand the form of the nutrient your specific species accesses. As an example, your fish can't ingest NO3-; they need nitrogen from an organic macro molecule such as protein. However, your zooxanthella can utilize NO3-. You have to look at the needs of the organisms to use the model correctly. And to your point on Amino Acids specifically: Amino acids are the building block of protein. When any cell; bacterial, plant, animal... Any cell goes to make a protein: It firsts has part of it's genetic code transcribed into RNA, that RNA seeks out a Ribosome and conducts a process known as translation (Biology calls this the "central dogma"). That Ribosome constructs a protein by combining Amino Acids in the sequence direct by the mRNA. There are roughly 20 unique Amino Acids used by all live on earth. So by dosing Amino's, you are ensuring the organism has ample amounts for growth of new tissue. Instead of waiting for the organism to synthesize it's own amino acids, or ingest it from another source, and convert it into a usable form. However, if you dose to much, it breaks down and spikes N & P among other things. Again, the rate is specific to the growth rate of your tank. He's driving growth as fast as possible, so he sees a benefit to using a large amount. But, it is very much relative to how fast can your corals grow? And as he said, if you're new. Go slow. 95% of reefers don't need this. I'm talking at the level of professional agricultural production (in which I have a degree, and work), as is Mr. Credible who operates a coral farm. This isn't a conversation for a 55 gallon, or a 120 gallon in someone's living room.

Is Justin's article publicly available? Where can I find?

Great video and information 👍🏾 I can't believe it potassium thas high. And me thinking, that is my issue.

Okay, let me see if I was paying attention, go home and pour a gallon of potassium in my reef ? 😳😂 I’m kidding people. Fascinating subject matter. Sure the dude appreciates you giving him a marvel character last name too.. 🤣😂🤪🥳.

450? keep going Marc! I wan to see 600!!! lol

Potassium in his reef tank.. sugar in his other tank

Its my first, "First" comment. 😀

4:18 i already can't take any of you seriously when it comes to chemistry. Ima click out of the video. Next.