# Too much UV killing my plants?



## btcoma (Apr 21, 2010)

I have plants (Cabomba and Amazon Sword) in my turtle tank.

So I use Sun Glo 5.0 (26W) shining on them for 12 hours a day.

The plants were looking healthy for the first 3 weeks. I have then noticed browning and "burnt-spots" on the leaves and lots of brown/hair-like algae.

What's my best bet to fix this problem  ? Much thanks in advance!


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## Fish_Man (Apr 9, 2010)

Instead of 12hrs a day.. should really only put it for 8-10hrs a day

get some algae eating bottom feeders or shrimps


How big is your tank?


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## btcoma (Apr 21, 2010)

Fish_Man said:


> Instead of 12hrs a day.. should really only put it for 8-10hrs a day
> 
> get some algae eating bottom feeders or shrimps
> 
> How big is your tank?


tank is 55g.

Umm I also have a basking spot light (60W) atop what's called a basking area (made with acrylic plastic), two 26W 5.0 UV and all three light fixtures are set on 12 hours a day. Question, does the basking spot light account for plant growth as well??

Btw, I do have shrimps, corys and oto's already but the algae is growing by the hour it seems.


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## igor.kanshyn (Jan 14, 2010)

Remove some algae that you can remove by hand.
Decrease you lightning period to 8 hours and look how it's going. If it will be fine, start to increasing it gradually.


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## bae (May 11, 2007)

btcoma said:


> tank is 55g.
> 
> Umm I also have a basking spot light (60W) atop what's called a basking area (made with acrylic plastic), two 26W 5.0 UV and all three light fixtures are set on 12 hours a day. Question, does the basking spot light account for plant growth as well??
> 
> Btw, I do have shrimps, corys and oto's already but the algae is growing by the hour it seems.


The 60W spot light is an incandescent, and does contribute to plant growth, but half or less what the same wattage of fluorescent would. Overall, your tank is only getting about one watt per gallon, which is a low light situation, especially in a deep tank like a standard 55. Cabomba is a high light plant, and Amazon swords like medium to high light.

I think your problem may be feces from the turtles providing more nutrients than your plants can take up, so the algae is taking over. Test your water to see if you need to do more frequent or larger water changes. Add more plants to take up nutrients. I'd recommend vallisneria, but I think the turtles might tear it up by swimming around in it. You could try some floating plants like hornwort or guppy grass that aren't harmed by being torn up a bit.

You don't say what kind of turtles you have, but many of them will eat both plants and fish.


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## btcoma (Apr 21, 2010)

Hey Thanks for the response. I checked with Exo Terra, the basking spot lamp give out UVA rays, unlike normal incandescent household spot lamps, not sure if it makes a difference. So fluorescent lights contribute more to plants than the same wattage of incandescent would? I didn't know..

Anyhow, it's a male map turtle and it does like to tear things apart but the cabomba is planted in the background and the swords are sturdy enough and doesn't appear to be a problem. Though my turtle is rare in terms of appetite; he doesn't eat anything live/moving. Fishes, shrimps and snails have been safe up to 2 years.



bae said:


> The 60W spot light is an incandescent, and does contribute to plant growth, but half or less what the same wattage of fluorescent would. Overall, your tank is only getting about one watt per gallon, which is a low light situation, especially in a deep tank like a standard 55. Cabomba is a high light plant, and Amazon swords like medium to high light. Thank you for the recommendation, I will go do some research on it.
> 
> I think your problem may be feces from the turtles providing more nutrients than your plants can take up, so the algae is taking over. Test your water to see if you need to do more frequent or larger water changes. Add more plants to take up nutrients. I'd recommend vallisneria, but I think the turtles might tear it up by swimming around in it. You could try some floating plants like hornwort or guppy grass that aren't harmed by being torn up a bit.
> 
> You don't say what kind of turtles you have, but many of them will eat both plants and fish.


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## bae (May 11, 2007)

btcoma said:


> Hey Thanks for the response. I checked with Exo Terra, the basking spot lamp give out UVA rays, unlike normal incandescent household spot lamps, not sure if it makes a difference. So fluorescent lights contribute more to plants than the same wattage of incandescent would? I didn't know..


The wattage is the amount of energy going into the lamp. The lamp outputs it in light and heat. Incandescent bulbs produce about 90% heat and 10% light. Fluorescents, IIRC, produce about 80% heat and 20% light, so you get twice the light with the same amount of energy with fluorescents. Fluorescents generally produce more of the wavelengths that plants use than incandescents do, unless they are special high temperature ones like mercury vapor. The basking light is mostly to provide heat for the turtle, so an incandescent type bulb is what you want.

If your tube is outputting in the UV, it's outputting less in the visible spectrum that plants use. Again, you've got 52 watts of light in a 55 gallon tank, which is a low level for plant growth.

I think your problem is (1) not enough light getting to the bottom of the deep tank (2) too much nutrient from the turtle promoting algae growth. You can add some floating plants, which will be near the lights, to absorb more nutrients, increase your light to encourage more growth from rooted plants, increase your water changes to reduce the amount of nutrients, add plants that require less light to grow, etc. You might want to test your water for nitrates to figure out whether it's the turtle output that's causing the problem.



btcoma said:


> Anyhow, it's a male map turtle and it does like to tear things apart but the cabomba is planted in the background and the swords are sturdy enough and doesn't appear to be a problem. Though my turtle is rare in terms of appetite; he doesn't eat anything live/moving. Fishes, shrimps and snails have been safe up to 2 years.


Every turtle is an individual!


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## igor.kanshyn (Jan 14, 2010)

bae said:


> The wattage is the amount of energy going into the lamp. The lamp outputs it in light and heat. Incandescent bulbs produce about 90% heat and 10% light. Fluorescents, IIRC, produce about 80% heat and 20% light, so you get twice the light with the same amount of energy with fluorescents.


It's four times, to be precise 

You can consider your 60W spot light as 15W of fluorescent. But, this light is not distributed so well as a fluorescent tube light. In the spot it glows you have a small algae farm, other places don't get enough light.


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## bae (May 11, 2007)

You're right, Igor. Fluorescents are more like 60/40, maybe better now that we have more efficient ballasts -- they run cooler, hence less wattage wasted in heat. That 80/20 didn't seem right to me either. That's the number for halogen bulbs vs conventional bulbs.

Thanks for the correction!


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## btcoma (Apr 21, 2010)

Thank you guys! that's some good knowledge there. I need to do some investigation here about the tank parameters. But I will most likely be getting a full spectrum light that is beneficial for the plants.


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## bae (May 11, 2007)

There's no real advantage in so-called 'full spectrum' lights -- cool white or daylight will work just as well for plant growth. Pick one you like the looks of.


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## btcoma (Apr 21, 2010)

bae said:


> There's no real advantage in so-called 'full spectrum' lights -- cool white or daylight will work just as well for plant growth. Pick one you like the looks of.


I went ahead and picked up 2x 26W GE 6500K daylight fluorescent bulbs


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