lighting questions

[gr8nguyen1]

i have a question concerning lighting. i want to know what lights would promote the least amount of algae. my tank dosen't have any live plants.
i currently have a 48" current usa satellite fixture with a 10,000k smartpac 460 actinac bulb.
i started to notice some algae today even though my tank is only about 1 month old. i have the lights on for only 7 hours a day. can someone recommend a light replacement that won't promote algae growth

[Spardas]

Any common fluorescent lighting setup will be fine. Also, you can just get those magnets cleaner and just swipe the tank everyday on the sides. Get some BN plecos for the bottom and clean the tank every month or so and you should be good with the algae.

If there is green water, just stick a UV sterilizer unit into the setup and it'll clear up in a few days.

[gr8nguyen1]

whats considered "normal" i mean i'm currently using a 10,000 k 460 actinac compact flourescent. is that ok. i've read they higher the light intensity the more prone to algae breakout you are

[waters10]

whats considered "normal" i mean i'm currently using a 10,000 k 460 actinac compact flourescent. is that ok. i've read they higher the light intensity the more prone to algae breakout you are
You have CF bulbs, which put out quite a lot of light! By normal light, I'm assuming Spardas was talking about T12 bulbs.

What you can do to address your problem, is move your fixture higher. Light intensity reduces a lot by even a couple of inches. Anything would help, but I'm guessing that with no plants, you might want to move quite a few inches ...

[gr8nguyen1]

what if i place a glass cover over the top of my tank? will that decrease the intensity of the light. i've read that the 6,700k light is actually stronger and more powerful for plant growth than the 10,000k how is this possible

[waters10]

what if i place a glass cover over the top of my tank? will that decrease the intensity of the light. i've read that the 6,700k light is actually stronger and more powerful for plant growth than the 10,000k how is this possible
I don't think glass cover will make much of a difference honestly. I'd either move the fixture up, replace it or another option, is to add some floating plants to provide shade and use some of that light.

There's very few difference between 10k and 6.7k color temperatures regarding energy available for the plants. Here's a good read (http://www.plantedtank.net/forums/837592-post21.html) with some tests showing what affects energy available for the plants. You can read that whole thread. There's more info there if you wish.

Hope this helps.

[gr8nguyen1]

waters10 thanks for the advice. i guess i'm gonna try to move it further away from the tank. floating plants might be a good idea, but it might be a hassle to deal with if i have to do daily wc. but what floating plants that require low lights do you recommend

[waters10]

waters10 thanks for the advice. i guess i'm gonna try to move it further away from the tank. floating plants might be a good idea, but it might be a hassle to deal with if i have to do daily wc. but what floating plants that require low lights do you recommend
What kind of filter do you have? Floaters are a pain if you have HOB! I don't think they are too bad to do water changes.

I only have experience with 2 types, frogbit and salvinia minima. They are prolific as most floaters. There are others available, just do some search.

Good Luck!

[gr8nguyen1]

but won't floaters promote algae growth since they and algae are plants?

[waters10]

but won't floaters promote algae growth since they and algae are plants?
Sorry, not sure I understand your logic here.

Basically, floaters will block the light from hitting the tank, while using that light for growth. That means less light available for algae. That's the idea.

In a tank with plants, algae and plants compete for light, co2 and nutrients. Plants can outcompete algae, so the key there is to provide everything the plants, so there are no left overs for algae. Easier said then done, since different plants and algae have different uptake.

In a tank with no plants to compete, there's always risk of algae. But light is the key for photosynthesis. There's always at least a little bit of co2 and nutrients in the water column, so the only thing you actually have control of, is your lighting. So you have to control that, by either reducing light available, or using some of that light with plants, in this case, floaters.

Hope this helps.

[gr8nguyen1]

what i meant to say was that my past experience with growing live plants is that the algae always seemed to outgrow the plants. sometimes the leaves of the plants would have algae growing on them. my bad luck with plants was that the algae always seemed to absorb the nutrients and lights even before the plants. thats why i decided this time not to go with plants. so i might even lower the lights some more. but i am only keeping the lights on only 6-7 a day.
what do you think about adding some purigen to my canister filter? hopefully it will absorb all nutrients before the algae can?

[Wahter]

what i meant to say was that my past experience with growing live plants is that the algae always seemed to outgrow the plants. sometimes the leaves of the plants would have algae growing on them. my bad luck with plants was that the algae always seemed to absorb the nutrients and lights even before the plants.

That only happens if the environmental conditions are not idea for the plants to thrive. Healthy plants will beat the pants off many algae. :)

You can keep water sprite (make sure you get the real water sprite - Ceratopteris thalictroides sometimes Hygrophila difformis is confused as water sprite) as a floating plant. That is easy to keep and shouldn't get overrun by algae (water sprite grows fairly quickly).

Ceratopteris thalictroides
http://www.tropica.com/productcard_1.asp?id=005A

Hygrophila difformis
http://www.tropica.com/productcard_1.asp?id=051

Hope that helps,


Walter

[gr8nguyen1]

wahter, thanks for the advice, the lfs sells h. diformis and labels it as water sprite. can i use this plant because they have a lot of it for sale.

[Wahter]

wahter, thanks for the advice, the lfs sells h. diformis and labels it as water sprite. can i use this plant because they have a lot of it for sale.

although the plants look similar, Hygrophila is actually a stem plant (generally not the best type of plant to grow floating at the surface), whereas the water sprite is actually a fern and it does excellent as a surface floater.

The best way to tell the difference is that the leaves on the Hygro grow out along the stem, where as the leaves on the water sprite grow from either the crown (central part at the base of the plant) or on other leaves.

Water Sprite is pretty common and easy to keep - I can't image any LFS not being able to order it. The big discount chain stores like Petsmart usually don't carry it, but they do sometimes carry the Hygro.

Hope that helps,


Walter