# Is it possible to have to much light?



## Themuleous (Jun 6, 2006)

Hi All,

Well having properly redone my nano, I was fully expecting a nice HC carpet in the three weeks its been running. However, I've ended up with a complete mess and now the HC looks shocking once again. Since seeing Zig's HC carpet in his tank and knowing that he used the cheapo bulbs (as I sent him them!), I'm wondering if upgrading to 2x24w T5 lamps was such a good idea after all? So my questions

Is it possible to have to much light?

I am now thinking that the increased watts together with increased penetration from the T5's in such a short tank (8" tall) is the reason my HC is dieing? I.e. it cant cope with the massive amount of light? Having tested Im running around 4ppm PO4 and 40ppm NO3, no fish to this isn't a problem. CO2 is easily 30ppm if not 40ppm and am using a drop chekcer wtih AE 4dKH water. I add 2ml TPN every other day after the 50% water change. Substrate is EC. All in all I know that plants are getting everything they need!!! but still no growth.

As I said I've seens Zigs HC and wonder if I should swap back to the T8's and save the T5 for when I upgrade my 60lt?

Any thoughts?

Sam

EDIT - Apart from a very small amount of BGA there is no algae in the tank, for once!

EDIT - I dont get much pearling either, lots less than when under the T8's, could this apparent slow growth be a 'defence' mechanism of the plants, i.e. they shut dwon in uber high light to stop themselves growing to fast and thus creating problems for themselves? 

EDIT - Tubes are 1x arcadia plant pro, 1x D&D midday so they should be ok. My only other thought on the lighting front is that the luminary isn't running the bulbs at full power for whatever reason? But I didn't think it was possible for a bulb to run if it wasn't getting enough electricity, i.e. a 20w bulb won't run if you give it 15w, but than again I’m no electrician. If its not the light I guess the only thing it could be is the PO4 and NO3 solutions, they are getting on for a year old now, but I wouldn't think NO3 dissolved in water could 'go off' i.e. become a form that the plants can use?


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## Freemann (Mar 19, 2004)

Hi
I think if your tests are accurate, most probably your NO3, P amounts are the ones that cause you your problems and not the lights. In my opinion 4ppm PO4 and 40ppm NO3 is way to much, you create toxic conditions, try reducing NO3 to around 10-15 ppm and PO4 around 1ppm, keep you K a bit higher than what is added from KNO3 (Edward's 1/1.33 NO3/K ratio sounds nice) dose enough Fe, TE so no yellowing is present and see what happens.


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## Themuleous (Jun 6, 2006)

I'll give that a try, thanks


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## Edward (May 25, 2004)

Themuleous said:


> Is it possible to have too much light?


 Absolutely not. I don't know how large your aquarium is but if you feel like the light is too strong, you can shorten the photoperiod. 



> Substrate is EC.


 That's one reason. You need to flush the aquarium often because this substrate leaks unwanted chemicals. 



> All in all I know that plants are getting everything they need!!! but still no growth.


 Obviously not. The plants are not getting everything they need. Feed them a proper fertilizer. 

Edward


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## Themuleous (Jun 6, 2006)

Hi Edward,

What kind of chemicals does EC leak?

For ferts I add PO4 and NO3 as per EI with tropica plant nutrition of 1lm per day on a 24lt tank. I thought TPN was the best fert you could get?

Sam


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## Edward (May 25, 2004)

Themuleous said:


> Hi Edward,
> 
> What kind of chemicals does EC leak?
> 
> Sam


 Read the Eco product label, there are chemical elements never needed by plants. The most noticeable issue was GH, Ca, Mg and KH / pH. There was also a manufacturer recall, customers could send it back.


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## snickle (Apr 8, 2007)

It is actually kind of a trick question. Yes, you can have too much light, but you would have to work really hard at it. 500W of MH on my 2.5G Nano would probably be a bit much.

Your Nano is about 6G if I do my conversion right. I run 2x13W on my 2.5G nano. No issues.

I would suspect your problem is not light.


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## Overfloater (Apr 2, 2004)

You can never have too much light for the plants.... but you can have too much light for your skill level


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