Hi Bob,
I use multiple methods to maintain water quality because it works best for me. I rely on algae a lot to remove nutrients but it is not the total solution, nor even a major contributer to overall water quality. Algae is just a single tool. I do not believe there is a single filtration system that does it all. I'm in favor of keeping algae in reef systems, just not Caulerpa near any corals. Algae is NOT able to fix the effects of using tap water in all locations. Saying that "if water is fit for human consumption then it is fine for corals" is wrong. Dead wrong...
To answer your questions:
"1) The value to shoot for is obviously .024ppm copper because the tanks are already successful reef tanks."
Feel free to shoot for 0.024ppm copper. It's your tank. I can tell you that delicate animals like Linckia and many of the larger snails will not live a full life at that level. I have and will continue to maintain NSW levels of trace elements where possible. Anything else is probably going to be detrimental. I guess the plus side of a copper level that high is that your fish are probably never going to get Ick.
Perhaps there was an implication that the tanks in the study were successful reef tanks. Based on some of the numbers I saw for water parameters I doubt they all were.
About the only conclusion I can make about the state of the aquariums is that they were all able to grow enough Caulerpa to be harvested for a study.
"2) the input values for the water in the tanks is unknown. If the tanks used .025 ppm copper input water the copper was only lowered by .001ppm. If plant life traps the copper int its cells, obviously higher copper in the water would mean more copper would be removed."
No, the tank water values varied from 0.0004ppm as the low to 0.038ppm as the high. I'm not a scientist but I didn't see any correlation between water copper level and algae copper level. I'll try to find the raw data again and look. The sample size was too small so there could be a link that this study just didn't show. There was a very definate link for other elements though, especially Iodine, Aluminum & Iron so Caulerpa is very successful at removing those elements.
"3) if the tanks used tap water and were successful my point is already proven."
This would require a new study. The participants that used tap water had extreme levels of copper. But, there are other factors that could contribute to Copper levels including Salt mix, and any fish food that contains chiton from crustaceans.
"4) if the tanks used ro/di water then where did the .024 ppm copper come from? Unless ro/di does not remove copper."
RO/DI removes Copper. Copper is added mostly through tap water, salt mix and/or fish food.
"And all reef tanks I have seen here are teaming with plant life.
"
You must be referring to Coralline because most of the reef tanks in the picture contest didn't have any macro algae showing in the picture. Perhaps there's a smudge on your glasses that looks like a plant when you're viewing pictures of reef tanks.
We're just going to have to disagree on this issue Bob and that's OK. In my experience Tap water doesn't work for reef tanks and in your experience it works fine if you have a lot of algae as well.
What types of corals are you keeping? Perhaps that's a factor. Maybe the types of corals you keep do better with the elements provided by tap water?
