To Much Light?? 2x65Watt

[Mussa888]

I was wondering about too much lighting! I can't seem to get a straight answer. I have a 20L, planted 2-3 weeks running. I have a Power Compact Flour. dual 2 x 65 watt, 1 daylight 10,000 and one Blue Acantic, with moonlight! I run the daytime for the first 6.5 hours in the day and the Blue for the other 6.5 hours a day. I'm having great luck so far, but I just want to make sure that's not too much light. I'm getting some brown algea and wonder if it's from the lights. Ph 7.2, Nitrates 0.0, Nitrites 5-10 ppm, ammonia 0.0ppm, co2 hagen unit. Thanks

[amanda huggenkiss]

I think brown algae is usually indicative of low light.

When you say blue actinic "with moonlight", do you mean you're using the actinic bulb as a moonlight? Or is it a 50/50 type thing?

I don't have any personal experience with them, but from what I've heard, actinic bulbs do nothing for your plants, but apparently are great for algaes. So even though you're giving your plants 13 hours of light, only about half of it is useable.

If I were you, I'd scrap the actinic, run the 10,000k for a solid 10 hours, and then run a moonlight in the evening if you want to see nocturnal activity.

[GDominy]

Actinic Bulbs are great at growing Brown algae, but not plants.. I would only run your actinic for an hour in the morning for sunup appearance and an hour before bed for sundown.. you could run the other daylight bulb for 10-12 hours and you should have better luck with your algae problems.

You have a very new tank that is still establishing its cycle as well.. wait another 4-6 weeks and everything should settle down a bit.

[trenac]

The actinic blue does nothing for plant growth but dose not hurt either. I have a 130 watts with one 50/50 bulb & one 6500k bulb over a 20G high that I run for 8 hours a day because of the wattage. Once I got my nutrient balance correct I have no problems with algae.


I would give your tank another week or two to seattle in and then start dosing to get your nitrates up to 10ppm. Test phosphates & keep phos at 1ppm. Your C02 should be keep between 20-30ppm and this is hard to do with the Hagan system. I had one on my 20G long and could get only 14ppm of C02. All this will help keep algae in check.

[Mussa888]

Thanks for all the help! I bought the unit as is, so I haven't changed the bulbs, I heard the blue was a better spectrum for plants?! I'll run the daytime longer than, for the past few days I have been running them together fo 9 hours. Is that too much light?! I'm just trying to learn the balance between good and just getting algae. PS The moonlight is another plug and is only used at night, if at all. It's an USA Orbit Dual Unit! Is there another power compact bulb that I could be or should be using for this unit?!

[2la]

Originally Posted by trenac

The actinic blue does nothing for plant growth but dose not hurt either.

Let's stop and think about this for a moment. Find the wavelength at which actinic blue's peak. Find the absorption spectra for the various chlorophylls and accessory pigments. Line up the spectra, and you'll that there is significant overlap in a very discrete range of wavelength. Now explain how a plant wouldn't have a single physiologic reaction to that light.

[SueNH]

I've got the Orbit unit too but I had the vender change the actinic out for another daylight. Plants grow like nuts. I'm very happy with it..

Use the legs. It does heat things up a bit.

The daylight bulbs are dual things, 10,000k and 6700k. Must be each light bar on the bulb is different?

I would think with the shorter 20 gallon the 2 bulbs would work nicely. The actinic would give a pleasing tint to the light and the one other daylight would charge the plants.

Brown algae just sort of happens with new tanks. Ottos love the stuff.

[trenac]

2la...In my experience talking with others & reading articles the actinic blue is used in marine tanks for coral growth. The benifit that freshwater plants get from it is little to none. Plants benifit from long-wave red spectral regions. Plant bulbs with a proportionately high output of red & blue light is best for plant growth.

[glass-gardens.com]

Plants need red AND blue wavelengths, too much red and you get spindly growth. Myself I prefer a 6500 bulb that leans more towards the blue, but that's just what works for me.

In the long run even cool white will work if it's intense enough, but 6 / wpg is going to cause some algae problems if you're not on top of the water chemistry.

Brown alage in a new tank is rather common from my experience, it should go away if you scrape what you can, do a good gravel vac and keep on the water changes.

[2la]

The absoluteness of the assertion that the actinic component does "nothing" for plants is its own downfall. Most actinic blue lamps feature a spectrum with a pronounced spike at about 420nm, which coincides with one of the peaks in the absorption spectrum of chlorophyll a (and also falls within the range of beta-carotene's absorption spike). I'm very interested to hear the explanation of how photons emitted at around 420nm and subsequently absorbed by Chl a (or beta-carotene) fails to elicit any physiological response from the plant whatsoever. Though I agree that there are better alternatives (which was not what I was contesting), the notion that an actinic component does nothing for plants is dogma commonly passed down through the aquatic gardening ranks but wholly unsupported by science and experience. I know of a few aquarists have used actinics over planted tanks with good results, though my own preference lies with other bulbs.

[trenac]

I also use a 50/50 bulb along with 6500k bulb over one of my tanks with great results. However is the benifit coming from the actinic or the 6500k bulb. IMO, it is the 6500k bulbs from all I have learned since I have been keeping planted tanks. However with all this fuss over actinic lighting more needs to be taken into consideration when growing aquatic plants to their full potential.

[2la]

Originally Posted by trenac

However is the benifit coming from the actinic or the 6500k bulb.

If you can (or anyone else) can answer the question of "how photons emitted at [and] around 420nm and subsequently absorbed by Chl a (or beta-carotene) fails to elicit any physiological response from the plant whatsoever," then I'll be convinced that the actinic portion of a 50/50 lamp contributes nothing to plant growth whatsoever. As it stands, I just don't see the science behind it.

In fairness to everybody else, Mussa888 contacted my privately for more help on this topic (seeing as I managed to steer it off topic a bit), and my reply was thus:

For a 20-gallon tank (and a shorter one in height, at that), having 65 watts of PC lighting over it should fully suffice for growing even the most difficult of plants. The full 130W, as you seem to have already figured out, would probably have been considerable overkill. However, I think the staggered lighting schedule isn't very beneficial to your plants. Higher plants (versus algae) need some time to ramp up to maximum photosynthetic rate, and that means leaving the light on for at least about 10 hours or so a day. By switching to a different light with different spectral characteristics (and possibly intensity as well), the plants need to readjust to what's given to them. Algae, on the other hand, can adjust on the fly, and you may be giving them an edge by switching over to the different lamp halfway through the day.

That said, I think the easiest solution would be to run your 10000K light for the whole 10-12 hour duration and leave the actinic blue out of the equation. However, if you have any more specifications on 10000K lamp (its spectrum, in particular), I'd be interested in seeing them. If you can't find any information, you can provide me with the lamp's name or tell me what's printed on the white plastic at the base and I'll try my best to find out as much about it as I can.

With your lighting as intense as it is, I'm concerned that you may not have enough CO2 in your water. If you can measure your dKH (carbonate hardness in German degrees), that would be helpful. What type of filter are you using? I'm also curious as to your fertilization routine, if any.

The good news is that high light or low light, brown algae often appears in the initial stages of a planted tank. Usually it disappears in time and may give way to another type of algae problem, or you may not have any other algae at all if you've found the magic combination of lighting, CO2 concentration, and fertilization.

[trenac]

2la... No I can not answer that question for I'm not a scientific person. Hopefully someone else will be able too. I posted what I did from all that I have read on forums & from info that I have gotton from other sources like the fish specialty store in my area that deals only in fresh & salt water setups. Maybe all the info I have gotton from different sources is flat out wrong, but I do not think so. The benifit from actinic blue lighting if any is small enough for me not to recommend using it. This is my opinion only and others will have their own opinions on the matter and that is great, for this is a free country.

Now on the overkill on the 130 watts over a 20G tank. I know this now but not at the time I purchased the fixture for I was just getting started in the hobby. With the setup I maintain I have found that running the lights for 8 hours daily with the right balance of ferts, C02 etc. that my tank is healthy, the plants grow like mad & the only algae that is present is a little thread algae which grows only on the Java Moss. I have also read other sources that say, less than 10-12 hours of daily lighting is not benificial to plant growth but I have yet to see that in my particular setup. But everyones setup is different and others has to find out what works best for them.

Thanks for everyones input...With all this said I think I'm finished with this subject.

[rkundla]

Originally Posted by 2la

If you can (or anyone else) can answer the question of "how photons emitted at [and] around 420nm and subsequently absorbed by Chl a (or beta-carotene) fails to elicit any physiological response from the plant whatsoever," then I'll be convinced that the actinic portion of a 50/50 lamp contributes nothing to plant growth whatsoever. As it stands, I just don't see the science behind it.

It's about time that people question the myth that actinic light is worthless in the freshwater planted aquarium.

We all know that actinic bulbs exist to fill a particular lighting need in the marine aquarium because the corals and other marine life need light at the appropriate wavelengths they have evolved over time to use in deep ocean water.

Botany tells us that terrestrial plants use both red and blue wavelengths to control certain growth mechanisms, like flowering and producing fruit, etc...

But to a plant, photons are photons. If the photons arrive on a wavelength that is compatible with the receptors common to all plantlife, then the plant will be able to utilize its energy.

My question is how much light energy comes out of an actinc and is it enough to drive freshwater plant photosynthesis? Will utilizing blue light only have a specific effect on freshwater plants? Are they too squat? Leggy? Will they flower or put out babies? Big mysteries never fully explained except in research laboratories and universities.

I wish some botanist with a Ph.D would come out and definatively state the effects of actinic light on non-coral aquatic plantlife. Anyone know a botanist or a graduate student looking for a thesis idea?

Ron