I'm semi-new to aquarium plants... I'll fill you in on my setup first, then ask my question. I have a 10 gallon, set up for 6 months, 1.5 WPG, with elodea densa, anubias nana, and anunbias barteri. Gravel substrate, no ferts or CO2. I have noticed some dark green/slightly brown algae growing on the leaves of my anubias. The tank lights are on a timer, they come on at 7am, off at noon, on again at 4pm, off at 10pm.

My question: I have heard that any more than 12 hours of light causes algae growth. I got the light timer to keep my hours down under 12. Is it OK to have that blackout period in the middle of the day? Will it kill the plants, or help to get rid of the algae on the plants? Currently, I lightly scrub the algae off the leaves of the anubias with a toothbrush (not mine!!!) during my weekly water change... but it's always back again in a few days.

Suggestions?

Thanks!

I'd just set it for 10-12 hours a day. Ramshorn snails would probably help.

Low light will actually encourage the growth of brown algae. You need to check your nitrAte level. If nitrAte is low, more light won't cause an algal bloom.

I just have mine on a 13hrs timer. No breaks.

I have found that growing plants takes a bit of experimentation as to what is good for your tank. I leave my lights on for 10 hours a day and that seems to promote good plant growth without too much algae. Every planted tank is going to have some algae, I think I would try adding a few algae eaters. Dataguru suggested ramshorn snails, and I have also found them to do a good job on brown algae (which is what is sounds like you have). I have also found otocinclus like brown algae, as do Chinese hillstream loaches.

Otocinclus can be a bit trickly to acclimatise, however, once you get some healthy ones, they seem to live a very long time. Hillstream loaches like some current in their water, and also like very well oxygenated water, so they may not be the best choice for a planted tank.

Also, when you make changes, such as changing the time of the lighting, you should wait about 6 weeks to see if the changes are working. It takes a bit of time to see the effect changes in a planted tank.

Good luck and keep us posted

Thanks for all of the suggestions!

I already have one snail, a gold brig. My little 10 gallon is currently overstocked, so I don't want to add any more fish. My NitrAtes are usually about 5-10 by the end of the week. Ammonia and NitrItes both zero.

So, the only variable I have left to play with is the light. Should I increase or decrease the length of time the light is on? Would you expect the 4 hour break in the afternoon to help, or hurt?

Thanks again!

I just found this mention about lighting breaks in a book. Interesting ...

In his Encyclopedia of Aquarium Plants (2003), Peter
Hiscock writes:
"Plants are able to regulate the rate of photosynthesis
relatively easily, and quickly respond to changes in light
conditions. In other words, they do not take long to warm up and start
photosynthesizing once there is sufficient light. However, algae are not as
biologically advanced as plants and need a long and relatively
uninterrupted period of light to function properly. It is possible to combat
algae in the aquarium by controlling the intensity and period of
lighting in the aquarium and creating a 'siesta' period. This is a period
of darkness that interrupts the normal day/night cycle in the
aquarium. If the aquarium receives 5-6 hours of lighting followed by 2-3
hours of darkness and then another 5-6 hours of light, the plants
will be relatively unaffected and receive enough light throughout
the day, but algae growth rates will be significantly reduced and may
even start to die back."

Hey Touchofsky, this is most interesting info. I might program my timer and see what happens. But then again, if the algae dies back, what will my bristlenoses eat?!

Well, after giving this a go for a few weeks, there has been a serious decrease in the amount of algae growing in my tank. I don't mind some algae, but I just don't want it growing on the leaves of my plants!!! There is still some algae growing on the back wall of the tank, which I leave for the snail and fish to snack on, but my plants look great! Success! Thanks for all the input!

Squeeker,
Hey, I'm glad you have had success in battling your algae problem. It does make the whole business of fishkeeping more enjoyable when you are not upset by the look of a tank

CaptK,
Let me know if you notice any decrease in the algae growth if you do try the "siesta" period. I don't have much algae in my planted tank, and I feed my bristlenose a chunk of blanched zucchini every day He loves it, and shoves it into his little hidey hole to snack on throughout the day ... away from those pushy goldfish

Well done, Squeeker!

TofSky: I haven't got an algae problem at the moment (touch wood) but I've filed this method away and if ever I was attacked by the evil green algae, I'll give it a go. Thanks for sharing.

I've never heard that! Going to try it out on one of my tanks I think, my male bristlenose is such a lazy bum either way he's not going to do a good cleaning job