lighting times

[gollum456]

hi, i just want to know, after having to reduce my lighting times due to algae, is having half the amount of light on for twice as long as before the same.

ie is 100w for six hours the same as 50w for twelve hours?

now i know this is not an exact science, i just want a rough idea as i would like to leave my lights on for twelve hours for viewing purposes. i have 4 T5 39w tubes which i used to leave on for 9 hours. so if i only put 2 on at any one time could i theoretically extend this to 12 hours?

thanks

 

[Dolly Sprint 16v]

gollum456

Hi - you have hit the nail on the head with your thread - "Had to reduce lighting due to Algae" the only way that you are going to eliminate the algae is to reduce your lighting period or if you want to run with your T5 lighting you will have to increase water circulation, quantity of fertz been added and increase Co2 levels dramatically.

You stated "I would like to leave my lights on for twelve hours for viewing purposes" why - that just compounding the problem - you be better of running the lights at 6 hours max @ 2 x 39 watts until you have sorted out the water circulation, co2 and fertz regime.

The more light you have, the more the plants will grow - but everything else as per the above has to be increased.

Regards
Paul.

 

[ghostsword]

I had similar situation, and the solution was just to put the lights when people are there to see it, from 1600 to 2100. Enough time and no algae issues.

I still have leds from 0700 till 2400, but just 40W for the 120L, and one bar is really high up.

 

[ceg4048]

...is 100w for six hours the same as 50w for twelve hours?

No, absolutely not. Although one could make an argument that the two conditions are mathematically equivalent in terms of total combined energy their physical impact is not the same.

Consider this; what would happen to you and your car if you slammed into a brick wall at 100mph? Suppose instead of a single impact at 100mph you repeated the collision 10 times at 10mph?

Light should be considered in terms of collisions, because that is how photosynthesis works. There are collisions occurring between the light traveling at 670,000,000 mph and the plant cells which must absorb the impact.

Similarly, if you spend 6 hours under the tropical sun at the equator, these same Ultraviolet collisions will fry your skin to a crisp, whereas 12 hours under, say, the Icelandic sun will hardly ruffle your feathers.

It is therefore the intensity of you lighting that is the fundamental cause of your algal blooms.

Cheers,

 

[gollum456]

errr, your last statement contradicts your first. you are saying 12 hours under the icelanic sun is not the same as 6 hours under equatorial sun. that i'm afraid backs up my theory completely!! two tubes of light is not the same intensity as say four tubes.

btw, i have the algae completely under control. i dont even have to clean the glass at the moment, (three weeks so far). i am just looking to re-extend my photo period from the seven hours at the moment. as it is i have two bulbs on for 7 hours with another two coming on for a 3 hour burst. i'm thinking if i dont have that burst i can extend the photo period.

now more unsure with the conflicting statements. comments appreciated though!!

 

[ceg4048]

Well, what I was trying to say was that the Icelandic sun, being of lower intensity would not do as much damage if you were exposed to it for twice as long as if you were exposed to the tropical sun which has higher intensity.

It seemed to me that in your original post, you were trying to equate longer duration of lower intensity to shorter duration at higher intensity. What I'm saying is that the comparison is irrelevant.

You are indeed correct that 2 tubes of light is not the same as 4 tubes assuming they are all the same wattage. However, 2 tubes of 50 watts will have equivalent effects as 4 tubes of 25 watts. Intensities are additive but duration has a much more complicated functional relationship which includes intensity as a parameter.

As Flyfisherman indicated, deleting the high intensity 3 hour period is a good first step in enabling you to raise the duration. Simply limit your tubes to two and carry on at the desired duration.

Hope this clarifies.

Cheers,

 

[gollum456]

thank you once again. i know i could have just tried this, but after finally getting the algae under control i didn't want to if it was definitely a no go. i will start by deleting the three hour high intensity and extending by 2 hours. i will be more than happy with a nine hour period.

thanks again