The Great Algae-Light Source Experiment

[Ace25]

I am a little confused on why you're so interested in making such a control scenario for the tank. Since none of us have the lab facilities really required to do this properly (daily lab testing of water) we just have to do the best we can with what we have. I would think as long as you are running multiple test scrubbers off the same tank, that will give you the exact same data as a control tank, ie, which lighting gives the best growth of algae. It shouldn't matter what the tank is like (sterile/ferts or full on reef) because every screen will get the same water. Even if the water isn't the most ideal in nutrients for the algae, it will still show us which lighting gives the best growth regardless of tank conditions.

Then again, maybe I am misunderstanding the goal here.

[Floyd R Turbo]

It's a valid question and I see where you are coming from. I guess what I am trying to get at is that let's say there is a slightly different type of algae or mix of algae that grows under LED WW only, Deep red/blue/ww mix, blue only, etc. Then let's also say that one screen is particularly efficient at growing algae. That screen will in effect out-compete the other screens, and then the results will be skewed. Granted that the end effect will show which combination of lights is the most effective, but what I am trying to measure is nutrient uptake accomplished by each screen driven by a given light source. That is truly useful data. Otherwise someone could step in and say the experiment was fundamentally flawed and while most of us could not care less what the hard-core detractors think, I don't want to give them any ammo either.

The other reason for splitting up the systems is to finally get some answers to the efficiency of nutrient uptake by algae in a scrubber configuration. By controlling dosage I can maximize growth results. Maybe this will shed some light on exactly how powerful scrubbers really are. Once that initial data is in the books, is would be very interesting to expand the experiment to include other forms of filtration for comparison and see how they stand up. I would call that experiment "Take the Scrubber Challenge" in honor of Pepsi. Which is way better than Coke according to the test results. But Coke has good marketing. See a similarity?

I can deal OK with using non-lab grade testing equipment, as long as it's a good quality kit like Salifert for Nitrate and a good meter for P, like Milwaukee or Hanna (the $200 one).

[Ace25]

LOL, I see, the RC people got under your skin too.. I was banned long ago from RC (2005) for trying to prove that actinic lights were far more important to corals than what most people thought. I tried to prove the wavelength and photosynthetic properties of actinic lighting and the mods banned me because they said actinics were only for visual use, to make us think the water looked more like the ocean, but had no real value to the tank. I challenged the almighty mods and gave scientific data and was banned for it. From that point on RC has been more of a joke to me than anything.

I see where your going with the experiment at hand... but to me, that seems like a different experiment. First experiment, test out various types of lighting and hopefully find a way to identify algae strains. Once we get the best type of lighting for maximum growth and which strain grows the fastest, we can move on to experiment 2, to see how much nutrient uptake the top 3 lighting and strain combinations can do, which is what you are talking about. Take the top 3 winners in experiment one and move them to experiment 2 to see if they correlate, ie. winner of Experiment 1 for most growth is also the one that does the most nutrient uptake. We may be surprised and find out the second fastest algae grower is the fastest at nutrient uptake.

[SantaMonica]

A note about multiple scrubbers on one tank: As one screen starts to grow, it will limit the growth of the other screen(s), making you think the other screens are less effective. This is easily observed in my testing of the 25: When one side is full, the other side does not grow, even if left for two weeks. Then when the full side is cleaned, the non-growing side grows and fills up in 3 days. And this is under the control of one cube per day.

Is similar to two water bottles connected by a tube at the bottom: If you add, subtract, heat or cool the water in one bottle, it will affect the other bottle.

[Ace25]

I would think the same decline in growth would happen along all the screens. At least how I picture it in my head. Say 5 independent boxes, each with a 3"x10" screen and its own pump, something like a maxijet 1200. If each small screen has its own pump, and you line all the pumps up together in the sump to intake water at the same point, I would think it could work. You would have to start them all and clean them at the exact same time. Each screen isn't big enough by itself to scrub enough, and on the LED experiment use only 2 LEDs per side in order to get growth spots since you want to see how much an LED will cover on its own. With LEDs you can mix a red and a blue and be able to see if algae grows better on the blue, red, or when mixed in the middle.

To take it a step further, you could test each setup for 30 days, then once you have the data swap the screens around in different lighting to see if the algae still grows or declines.

[SantaMonica]

No, as soon as one starts growing more, it's filtering will increase exponentially by increased water contact and growth area. It will then consume all nutrients and not allow the other screens to grow.

It's the parellel resistors situation.

[Floyd R Turbo]

That's exactly what I was getting at, thanks SM for confirming. The exponential growth factor is something I had not though of either, but it fits in with logic.

For instance, my current jury-rigged top-of-tank scrubber was at just enough growth to have about 1" of 3D at the bottom late Friday (day 4) and the 2nd (high) drain was dry. Now it's easily 3 or 4" in the middle (day 6) and the second drain is flowing fairly well.

[salty joe]

If 2 screens at once is a problem, how about running 2 screens on alternating 12 hr photoperiods? You could use an unlit sump and dose accordingly to mantain a consistant nutrient load. Maybe use nutrient loaded topoff water in an ATO. Wouldn't plain old amonia provide useful and easily measurable N? There has to be a similar chemical you could use to provide P. I'd bet Randy at RC would answer that one for you.

[Floyd R Turbo]

Today I had a conversation with a guy who has been in the hydroponics industry for 15 years. He had some very interesting things to say about light spectrum and intensity. I believe I finally have a good answer for the 3000K vs 6000K and up issue.

When I brought up T5HO and people experiencing better growth with the 2700-3500K spectrum, it threw up a flag for him. The issue, apparently is not that the spectrum is better, it is that the lower Kelvin rating is more intense. I can't recall all the details of the conversation (we spoke about many things) but this is basically what the K rating issue boils down to. The light given off in the red spectrums is more photosynthetically active than that in the blue spectrums.

I know this is going to raise some additional questions, mainly how do you also hit the blue peaks and with what amounts, but that may not matter. It has to do with vegetative growth vs flowering growth. I'm going to talk to him again and try to get this straightened out in my head.

We came about that point when discussing LED lighting for algae / hydroponic growth. A lot of the better results seen so far with LED lighting have been seen using lots of red (630nm) LEDs, and some good growth with 5W deep red (660nm) LEDs. That brought about a discussion regarding those. As it turns out, if you take arrays of the same wattage of 660nm Deep Red LEDs and 630nm LEDs, the 630nm Red LEDs will strongly outperform the 660nms, because they flat out are just that more intense. The reds are also more intense than the blues. This is why better growth is achieved with lights shifted toward the red spectrum.

This may not be the greatest explanation, but I'm working on it. For me, all the information I got out of the conversation pretty much put the nail in the coffin of the spectrum debate.

More to come.

[Floyd R Turbo]

One more thing to add. He did mention that to his knowledge, no experiments have been done (except for one by NASA, which I will now start to look for - SM, got that one?) to determine algal biomass growth rates under various spectrums.