# Silica / Phosphate (Planted tank)



## Kevinj87 (Aug 30, 2015)

Hi guys,

I have a brown diatom issue in my tank and was studying and researching many different cures.

I found that recently since 1996 a lot of the belief's have changed so I am trying to get the RIGHT information located in one spot.

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I am told that 0 phosphates = no plant growth and green algae
I am told that high phosphates means diatom growth

However I read that silica is the cause of these brown diatoms.
The question I have is ( are silica and phosphates the same ? )

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I need to get rid of this brown diatom problem and the only way to remove silica that I have found is by using "Phosphate" absorbs or killers, but I have read that by removing phosphates I will just worsen my case by causing harder to control green algae.

This seems like a no-win situation, is there ANY way to get rid of brown diatoms or silica without removing phosphates and hurting the plants and causing green algae???
:help::help:


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## CannaBrain (Oct 3, 2008)

Get something that will eat diatoms. Snails, otos, etc.


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## Kevinj87 (Aug 30, 2015)

Nothing that just removes silicate though huh?


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## toadpher (May 25, 2015)

I had a huge diatom problem till I got 4 Nerite snails in my 55g paludarium after getting my Finnex. I was told they will cycle out and my snails made a few days work out of them. Haven't had a problem with them since. Nerite's are cheap and easy and pretty cool too. I recommend them, plus they won't go crazy and over populate your freshwater tank.


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## DaveK (Jul 10, 2010)

Kevinj87 said:


> ...
> 
> However I read that silica is the cause of these brown diatoms.
> The question I have is ( are silica and phosphates the same ? )
> ...


No they are not the same. Silica is a "construction material" for diatoms, kind of like how calcium is the construction material for snail shells. Phosphate is the food for the diatoms.

As you have stated, you need some phosphates in a planted tank for plant growth, so you just can't get rid of it all.

You have several way to control diatoms. 

Find something that feeds on them. This method was covered by others above.

Use something to remove silica. API Phos-zorb is an example. It also removes phosphates. Note that the removal process gets them to stick together so the filtration picks them up. You need to clean the mechanical filtration media often for this to work.

Use something to remove or reduce phosphates. See above.

Use something that will kill them. If the diatoms are in the water itself, you can use a UV unit to kill them. It will not do much if the diatoms are just coating everything.

The source of silica may be from your tap water. You can get test kits for this and test it. You can use a RO/DI unit to remove them from your tap water, but this is expensive, and you'll them need to use GH and KH builder to give the water some hardness. BTW, RO alone is not a very good silica remover. You also need the DI section to really get it.


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## Kevinj87 (Aug 30, 2015)

DaveK said:


> No they are not the same. Silica is a "construction material" for diatoms, kind of like how calcium is the construction material for snail shells. Phosphate is the food for the diatoms.
> 
> As you have stated, you need some phosphates in a planted tank for plant growth, so you just can't get rid of it all.
> 
> ...


Thank you, this is what I needed. I appreciate anyone willing to take time out to help another. The only problem I heard with RO/DI water is that i work's great but the Diatoms can break down the barrier and start forming within a day of using RO/DI. I read a really intricate study on it with information from the man himself (amano)

I picked up another 4 Otto's so let's hope these guys are hungry. The Nerite snails I refuse to do, I had terrible experiences with snail's in the past (trumpet snails in particular) everyone raved about them and the amount of WASTE they produced alone was insane. The substrate become littered with waste from trumpet's.

I am going to use some Phosabsorb just to immediately lower the silica level's, I won't completely drain the water of phosphates etc.

I am going to have to investigate whether it is coming from the tap water.:confused1:


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