# Can indirect or direct sunlight cause diatoms?



## jhays79 (Mar 28, 2012)

My tank is a 46g bowfront I have setup in my living room, it's been up and running for 6 months now. I have diatoms in the sand substrate, and a fair amount on the plant leaves. The tank gets late afternoon sun for an hour or two. Do you think that contributes to the diatoms? I know my tank is still somewhat newly setup, and diatoms are normal in new tanks, but I've had them for over a month now, and they don't seem to be getting any weaker. I have three other tanks setup in my house, one of them has sand, the other gravel, none get any natural light, and I don't have any diatoms in them. Just trying to figure out if it's the location of my tank causing the diatoms or other factors. I would of thought that the sunlight would cause green algae if anything, not really diatoms. any thoughts?


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## Sajacobs (Aug 24, 2012)

My tank gets direct sunlight too....and I had a bad problem with diatoms. I ended up getting a bristlenose pleco. He solved the problem. That said other issues can cause diatoms, like silicates. Silicate can come from substrate, tap water and the sealant in the tank. You might want to investigate this issue to rule out where your diatoms are coming from.


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## jhays79 (Mar 28, 2012)

I've hung some dishcloths temporarily on the side of my tanks to see if blocking out the sunlight gets rid of my diatoms. I can deal with it on the leaves of the plants because the Otto cats and Plecos are taking care of that, but the sand is so ugly with the brown all over it.


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## puopg (Sep 16, 2012)

Sun puts out tons of PAR. Even in the shade, you'll get like 100-200 PAR. Direct its like 2k. So perhaps algae might be casued by sunlight since its pretty much instantly high light and if you don't have good CO2 it is possible. As far as diatoms go, i have had my tank in indirect/direct sunlight for a week or so but i never induced them. I mean look outside in rivers and lakes. They get direct sunlight all the time and im sure diatoms exist but are the plants literally covered in brown? Maybe stuff is eating it too fast? This I do not know but it seems to me that sunlight alone should not be the root cause of a diatom outbreak.


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## jhays79 (Mar 28, 2012)

That's what my initial thoughts were too. I thought it would have caused green algae, not diatoms?


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## micheljq (Oct 24, 2012)

Hello,

Sunlight, any king of light can cause algae or diatoms. But many people are able to keep a tank near a window without having algae issues. Some have their tank in direct sunlight for a couple of hours a day and have algae free aquariums.

It is a question of balance, being able to promote plant's growth so that they competition algae.

Mine is quite free of algae now after 4 months and it is just 4 foot near a big window but it does not get direct sunlight. I do not use CO2 or liquid carbon. I am just one example over a lot (excuse my english).

Michel.


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