Water quality measurement

[mkirda]

Randy and any others,

I am curious if you think there is any consensus, or can be any system that water quality systematically?

I've been trying to get my mind around this topic for a few weeks now, but realize that I'm no closer than I was.

In the scientific literature, we have subjective ratings from polluted to pristine, usually with no measurements attached.
In the reef hobby, there has never been any concerted attempt to quantify that would constitute 'good' water quality as far as I can tell.

Is this a pipe dream? Unachievable?
Or do you think we might be able to come up with a system to categorize tank water quality, and compare things in a meaningful way?

I'm looking forward to your reply.
Regards.
Mike Kirda

 

[AF Founder]

Mike,

I think the problem is that the questions you're asking haven't been answered yet. If you take the position that our tank's water quality must be as good as a pristine coral reef than there are available answers; eg., both nitrates and orthophosphates need to ne in the hundreths of a PPM. Nitrate on a coral reef is around 0.002, and phosphates are as low or lower. It appears virtually impossible to achieve that in a reef tank where there are fish that need to be fed.
Next month Randy Holmes-Farley discusses calcification and discusses at what concentration of phosphates calcification slows down.
We know what level nutrients exist at in NSW, but what levels are healthy and possible in man made biotopes is another matter entirely.

 

[mkirda]

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by Advanced Aquarist, Editor:
<strong>Mike,

I think the problem is that the questions you're asking haven't been answered yet. If you take the position that our tank's water quality must be as good as a pristine coral reef than there are available answers; eg., both nitrates and orthophosphates need to ne in the hundreths of a PPM. Nitrate on a coral reef is around 0.002, and phosphates are as low or lower. It appears virtually impossible to achieve that in a reef tank where there are fish that need to be fed.
Next month Randy Holmes-Farley discusses calcification and discusses at what concentration of phosphates calcification slows down.
We know what level nutrients exist at in NSW, but what levels are healthy and possible in man made biotopes is another matter entirely.</strong><hr></blockquote>

Terry,

Thanks for taking the time to reply.

I think most informed aquarists would attempt to replicate the reef biotope as accurately as they could, give adequate access to that information.
Certainly we would strive to approach levels that we would see in the reef environment.

I'd also stipulate that we know what levels are possible in a tank, from good to bad. (You should see some of the fish stores I've seen...) You mention nitrate levels on a reef of 0.002- One of my tanks ran at 0.009 for the better part of a year.

Now, what levels the corals can tolerate, vs thrive at... Now, that is a difficult topic. But I would hardly characterize it as insurmountable.
I'd guess that we might share some species, and that if we were to share the nutrient conditions of our tanks, and enough other people also were to, we'd get a large enough data set to work the parameters required to keep different species.

Getting back to the question though, do you think it is possible to characterize water quality in such a way that we could compare tank A and tank B meaningfully? It's a serious question.

Regards.
Mike Kirda

 

[AF Founder]

You said: "Getting back to the question though, do you think it is possible to characterize water quality in such a way that we could compare tank A and tank B meaningfully? It's a serious question."

That sure is a difficult question, because there are so many variables. For example, there is some evidence in scientific literature that a relatively high nitrate level is tolerable with a high alkalinity level.

Also, I remain convinced that reef tanks tend to peak after about a year in their ability to support a wide variety of invertebrate life, but that after that conditions, not easily measurable, decline. It will support some inverts, but not as many as when it was at peak. There is more than a little grain of truth in the argument that every reef tank ought to be broken down and resetup about every two or three years. With people with a big tank that idea is almost unthinkable. The question of course is what is causing the change -- it is not something or things that I have been able to measure.