Water Clarity

I think clarity of water is most of the times just a general perception by the eye. The "purists" would argue that in order to make a definitive comparison between clarity of water at different points in time or in different tanks, you have to take a picture of a reference object (like a white cutting board) through the tank with the same conditions (light, flash, f-stop camera settings, etc) and then make the comparison.

There unfortunately is no "color of water" meter that works for SW. Hanna does make one, but it is for turbidity of runoff water for streams, rivers, construction site runoff, etc (I tried it).

So we are left with rather rudimentary techniques. One thing you can do it find a 5 gallon white bucket and pull a few gallons into it and compare that to a bucket with freshly mixed SW in it. Then take pics with same ambient light and camera settings, etc.

 

Interesting, but my brain doesn't have time to process at the moment. Care to boil it down a bit? Not following how this relates to skimmer/scrubber relationship. Also how could we quantify algal stress?

 

This is interesting. I just spent some time learning a little bit more about hydrogen peroxide. I can now see multiple relationship pathways between algae and bacteria. There also might be some kind of connection between algae growing on rocks and HP. I wonder how this might tie into ORP measurements. I don't know many people that have measured ORP on a tank before and after adding a scrubber.

 

I think that you would not want a significant UV component to an algae scrubber light. There is some evidence that shows that there is a strong relationship between algae and bacteria. Such as bacterial biofilms forming on algae mats. I think adding a UV LED for instance might hurt things. But a deep violet might not. I would stay away from any light source whose purpose is sterilization.

 

I think a lot of the relevant discussion you are looking at (mainly from Ace) is related to display tank bacteria and the UV connection.

My only thing to add was something that Tony Vargas said when we were standing around chatting after our last frag fest, and that was that he said that if you look at tanks that have fish with HLLE, you will find there is no UV light in those tanks. Look at the tank with UV (under Metal Halide or T5HO) and you will find healthy fish, no HLLE. That's loosely paraphrased, but that was the gist of it.

I made a point of asking him what his thoughts were about LED fixtures with a UV component and he said that many are now adding this (Radions for instance)

But, in a recent phone conversation with Ricky on the subject of corals under MH/T5HO vs. LED, I am leaning much more towards sticking with my energy-wasting heat-producing T5HO and MH lamps for primary light, and maybe just supplement with some LED to take the edge off of the heat/power.

Basically that conversation was along these lines:

Take a coral grown under MH and put it under LED, it will looks awesome. Take the same coral a few months later and put it under MH again and it will look brown.

Grow a coral under LED and put it under LED and it looks fine and grows fine. Take that coral and put it under MH and it will look brown.

In both cases, after a few months under MH, the coral color will return.

So the conclusion is: If you have LED, stay with LED.

If you have MH and you switch to LED, everything will look superb then will fade out over time, 3-6 months, so you won't notice, really. Just don't switch back.

I have a feeling many coral vendors at fests know this. So they grow things out under MH and then show them under LEDs because the colors will really pop. Obviously, such a practice is a little deceptive. But I've heard of worse trickery