# How long does it take for diatoms to go?



## Pufferfish22 (Feb 6, 2011)

I am battling with diatoms covering my sand, glass, everything, I understand this is common in a new tank but how long will it take for them to go?

The man at the LFS said once you get them they never go away? If this is the case is it because I bought a second hand tank and they were in it? I thought they were a type of algae and surely the tank being stored dry for weeks would have killed anything in the tank along with the scrub with salt and loads of rinses out I gave it?

I've reduced the amount of time my lights are on for from 12 hours a day to 6, and I have 4 java ferns in there (it's a brackish 80l)

Could the diatoms be due to an old light bulb, should I change it or would they be due to the tannins released from my bog wood?


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## Byron (Mar 7, 2009)

Diatoms are an unicellular type of phytoplankton. They occur due to any combination of low light, the presence of silicates, excess nutrients and organics, and excess iodine.

Silicates are a type of mineral, about 30% of all minerals are silicates. Quartz, glass, and silica sand (sound familiar?) are some silicates. Silicates may be present in tap water. Iodine is an ingredient found in many aquarium additives. The excess organics and nutrients comes into play mostly in new aquariums where the water has not yet stabilized, and diatoms usually appear before more common green algae which itself will often limit the diatoms. 

Maintaining good water quality (regular water changes) is recommended. If diatoms persist in low-light areas it may mean silicate in the tap water, usually 3-4 ppm will cause diatoms; check with your water supply board who should have a list of substances in the water and see if silicate is included. Phosphate removers also remove silicates, as does RO (reverse osmosis).

Live plants help by keeping more stable water conditions. Increasing the light may help, but if the cause of the diatoms is organic/nutrient this will often result in green algae in brighter light. Some snails and "algae" fish like otos eat diatoms, but the latter obviously won't work in brackish water.

I dug around a bit and it appears the above holds for brackish as well as freshwater.


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## demonr6 (Dec 27, 2010)

A cleaning crew of three olive nerites.. diatoms are put on notice.


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## Byron (Mar 7, 2009)

True. Also noticed I missed something from the original post, the advice from the store is wrong. Diatoms occur in an aquariumfor a reason. If the "reason" [= conditions] is present in any aquarium, they will appear.


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## demonr6 (Dec 27, 2010)

I think it would be a good thing to know or at least try to learn why they may be happening, but in some cases the path of least resistance is the best to take. In my case it is the water. Ours is really bad so we have a water softener so the added silicates may be the contributing factor. Short of buying an RO system which is not the path I would prefer I went with the cleaning crew option.


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