# how do I dim correct light quantity?



## Al404 (12 Jan 2015)

Just bought the new 24w dennerle LED lamp, is dimmerable
my tank is just starting and is empty, how can i understand if i have enought light

my tank is 45L and no CO2


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## Julian (12 Jan 2015)

Algae is your indicator. Make small weekly adjustments until you start to see signs of it, then drop it back slightly when you do.


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## ceg4048 (13 Jan 2015)

Al404 said:


> my tank is just starting and is empty, how can i understand if i have enought light


You should look at it from the opposite direction. Too much light kills plants, so instead of worrying if you have enough, you should insstead assume you have too much. Dim the lights to about 15% for the first 6 weeks or so and then gradually raise them if necessary.

Cheers,


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## Al404 (13 Jan 2015)

@ceg4048 i did not know that, what are the symptoms of too much light?

actually i ave a problem with the dimmer, when the timer cut off power because when it turn back on dimmer would not power on lights unless i do it manually
http://www.ukaps.org/forum/threads/dennerle-scapers-led-problem.35762/


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## Julian (13 Jan 2015)

Al404 said:


> what are the symptoms of too much light?



Algae.


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## ian_m (13 Jan 2015)

Al404 said:


> what are the symptoms of too much light?


Too much light drives the plants to demand more CO2 (and ferts) and if not met the plants will die releasing organics into the water allowing algae to bloom and take over.

So start with "low light" until plants have "settled in" and ensure they have sufficient CO2 (and ferts) for the light level you are supplying.


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## Al404 (13 Jan 2015)

the problem is that dimmer doesn't work correctly so i need to solve that issue before :-/


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## ceg4048 (13 Jan 2015)

Al404 said:


> the problem is that dimmer doesn't work correctly so i need to solve that issue before :-/




Hi,
    In the meantime, while you troubleshoot the dimmer, you should find a way to prevent too much light from entering the tank. You can cover the light (or tank) with wax paper, or cheese cloth or any translucent material.

Cheers,


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