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Do two photoperiods actually help with algae?

Discussion in 'Lighting' started by Carissa, Aug 29, 2007.

  1. Carissa

    Carissa Guru Class Expert

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    I would like to know if this is true or not. Someone said that if you have your lights on for no more than 5 hours, then off for an hour or two, then back on for 5 or whatever, that algae won't grow because they need more than 5 hours of light in a row in order to multiply. This kind of sounds iffy to me but I don't understand the differences between algae and plants enough to know if it's bunk. Can anyone else answer this?
     
  2. riverrat

    riverrat Prolific Poster

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    I say its bunk!

    I bet if you wanted to do an experiment you could. Say you set up a 10 gallon tank with fish only and put 4 watts of light over it. Feed fish heavy and only turn lights on for two 5 hour periods a day with a siesta of an hour in between. I would be willing to bet that within a week or two at the most you would have algae, and a lot more of it on the way.


    I mean if someone says that with this condition algae wont grow why then must I add co2 and ferts to my tank. I simply go with 5 on .....siesta......5 on. The hole in this theory IMHO is big enough to drive a truck through. Lots of trucks.

    I can understand if you have more than one bank of lights to have lower light in morning, a noon burst of higher light and lower light in the evening. This might make more sense to me.

    I am not saying people who use this approach do not have successful tanks free of algae. I just don't buy that algae uses a timer to decide when its time to grow.

    I combat algae the "old fashioned way" myself. Concentrate on plants growing well , co2 , ferts , cleaning pruning. This has been successful for me. I have had tanks free of algae. All algae none to be found. Of course I would be lying if I said my tank is free of algae at the moment. Far from it. I let things go for a couple months and now I am paying the price. It happens and I will beat the algae again as I have in the past. Concentrating on good co2 and good plant growth.
     
  3. Carissa

    Carissa Guru Class Expert

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    I was thinking, you could take one tank, like a 20 long, and put a black divider in it. Then have one half with a siesta, and the other without (you would need seperate lighting). Same exact water quality obviously for the whole thing so that would eliminate that variable, and see how fast algae starts or doesn't. If I had the right shape tank I would probably try it.
     
  4. VaughnH

    VaughnH Lifetime Charter Member
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    Algae are far more opportunistic about starting to grow than plants are, so it seems to me that the divided photoperiod would be more likely to help the algae than the plants. And, the trouble with trying to test this is the extreme difficulty of keeping all other conditions exactly the same in the two tanks. One would really have to do a series of tests to make sure whatever effect they found would occur repeatedly. Doing something like that is way above my abilities.
     
  5. Carissa

    Carissa Guru Class Expert

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    That's why I was thinking if you took one tank, like a 20g long, and divided it, you would have identical water quality on both sides (water flowing freely between the two sides). To really make it the same you would probably want two filters and two heaters, or maybe none at all would be better. The only variable then would be the lighting, this would have to be pretty sealed off to make sure that each side only gets what it's supposed to. I would test it but I don't have any spare 20g tanks lying around, I think it would be too hard to seal off the lighting in a 10g (which is all I have in spare tanks right now) with such a small amount of surface area available on each side.
     
  6. VaughnH

    VaughnH Lifetime Charter Member
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    Doing the test in a single tank, with water mixing between the two areas would not be a good test. Algae could start up on one side, then move to the other in the water. Green water and GDA would migrate easily between the two halves. And, if the plants grew faster on one side than the other, you would have to be very careful to have very good water circulation back and forth between the halves or the faster growing side would deplete available nutrients for the other side. I think two separate tanks would be the only way to do this.
     
  7. ceg4048

    ceg4048 Lifetime Charter Member
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    I agree with this. There is more variation of algae causal factors within the same tank than could ever be correlated to lighting scheme. Variations such as localized flow patterns due to walls or neighboring objects bringing nutrients to individual leaves, localize ammonia concentrations, general vigor of individual plants and individual leaves on the same plant. Localized soil condition due to individual root patterns and root health. The manner in which ambient light in the room strikes the tank. Temperature variations within the tank. Local nutrient leeching from soil or leaves.

    Any conclusions drawn from a single tank would be speculative. Since it's impossible to keep everything the same across tanks or even within the same tank you would need to test hundreds of tanks of either configuration in order to draw conclusions that would be statistically relevant. The difference in the two configurations would have to produce results significant enough to take into account the normal variations that occur in most tanks otherwise you'd have nothing more than random results.

    Cheers,
     
  8. Carissa

    Carissa Guru Class Expert

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    Good point, I hadn't really thought about algae actually being in the water itself. I was thinking about doing it with no plants though, just a bare tank with water. If it worked and one side had less algae, you could disinfect the tank and swap sides with the lighting and try it again and see if the results were consistent based on the lighting after several trials. But if it didn't work, it still wouldn't be disproved, since perhaps the algae was just migrating etc. Lots of variables.
     
  9. Tom Barr

    Tom Barr Founder
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    A better method to address this is to ask a better question.
    Can we induce algae with or without a siesta?

    I think it'd be tough.
    I have a tough time figuring out why/how to set up such an experiment even.

    I know I can induce many species with all sorts of lighting times, as long as I have enough high intensity light. With less/lower light, then things start to change.
    That would suggest that this is not a method to reduce algae at all.

    Many have tried this method, but few report success.
    Much like many algae cure alls.

    Why?

    Because it does not address the cause of the algae, only treats the symtoms.
    Algae cures should be avoided in general and a basic understanding and focus on/about plant growth should be your approach.

    You'll have far less algae issues if you go that direction.

    Then algae "cures", siestas no longer matter, except for other reasons such as viewing, high temps in the middle of the day etc, more practical matters, rather than to cure algae.

    One author suggested this method, and it's been tough to get rid of ever since.
    It does not hurt anything and it's easy, so many try it and one person every so often claims success, just enough to keep the dang thing going........but folks have algae clear up for all sorts of reasons, showing cause is far more difficult, you are bound to have some success based on correlation and simply trying to correct an issue with better care etc after you see algae.

    Maybe is was more cleaning, more water changes, better more careful dosing etc........who knows.

    Regards,
    Tom Barr
     
  10. Gerryd

    Gerryd Plant Guru Team
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    Varied lighting periods

    Just my two cents as I read this same advice (ref below) and do this for the following reasons.........

    on: 9-3
    off: 3-6 pm
    on: 6-midnight
    off: midnight-9 am

    1. Ability to view the tank later at night (after work/excercise/etc) and still have a 10-12 hour photoperiod due to the 3 hour time off period. Remember, we keep fish/plants to enjoy watching them!

    2. Fish have period in mid-day with natural light only. I have many cardinals and they especially seem to enjoy schooling in the upper reaches during this time. Mid afternoon light is strongest in my apt, so the timing works well. A little direct sunlight gives the tank a nice shadow/light pattern that is very pretty at this time as the sun moves across the sky.....

    3. Reduce heat a bit during mid-day (MH lights are hot and so is S. FL), even thought lights have builtin fans. I have noticed a slight drop in temp during this time (80.1 - 79.2) that does not occur with the lights on during this same period (did not always have this pattern and I compared bef/aft), so assume this does in fact make a slight difference.....

    4. Matches South FL weather patterns by having off period from 3-6. You would be amazed how many times a week it rains during this exact time frame, you can set an alarm by it :D

    Reason author gave that I read (and as I understood it) was that algae take longer to begin assimilating nutrients/c02 than higher plants after the beginning of a photo period. Thought was that this would put the algae at some slight disadvantage and allow the plants to access the nutes first.

    Reference: Peter Hiscock, Encyclopedia of Aqaurium Plants (2003), pg 59 (siesta periods) :D

    Not sure if this is true or not and certainly defer to the experience/wisdom/knowledge of others, but the other benefits above work for me and my setup. My plants seem to suffer no ill effects that I can see doing this and have had many species at var times.....

    Just wanted to add my experiences to this thread/discussion.

    Thanks and have a great day!
     
  11. VaughnH

    VaughnH Lifetime Charter Member
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    One test that would be easy to do, or relatively easy to do, would be to set up a simple tank, one slow growing plant - anubias? - ordinary pool filter sand. Add some terrestrial plant food - with urea/ammonia in it. Then set up about 2 watts per gallon of light and run the lights on for an hour a day only. (The room would need to be darkened.) Watch for algae. If algae blooms, then it can't be true that algae require long periods of light to bloom. If no algae after a couple of weeks to a month, increase the time the lights are on to 2 hours a day, etc. The obvious flaw is that not all algae are alike. Green water algae could and probably would start growing, but that wouldn't mean that BBA or GDA or GSA would do so.
     
  12. Homer_Simpson

    Homer_Simpson Prolific Poster

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    I agree that you would likely have to replicate noon-burst or split photoperiod on 100's of tanks, keep all other variables(ferts, type of water DI or Tap, types of plants, fish stock, substrate, etc.,) to confirm beyond the shadow of a reasonable doubt the benefit of these as anti-algae measures. This would involve a significant financial cost not to mention time.

    While I know my experiences don't speak for everyone, under two identical 10 gallon tanks, with all other things being relatively equal, I found that noonburst and split photoperiod "appeared" to result in less algae(with the exception of Blue Green Algae). The difference was that the plants seem to respond better growthwise to noonburst lighting vs split photoperiod.

    Just my own observations, nothing more and nothing less.
     
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