# Caribsea Natural Sand leaching silicates producing diatoms?



## micheljq (Oct 24, 2012)

Hello,

Sand is made of silicates holded together with strong chemical bonds. 99,99% inert, no it cannot leach silicates in the water. It would take decades, centuries. It's like saying your aquarium glass leach silicates since glass in made of silicates too. It's an Urban legend circulating on the internet.

Michel.


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## Discusluv (Dec 24, 2017)

micheljq said:


> Hello,
> 
> Sand is made of silicates holded together with strong chemical bonds. 99,99% inert, no it cannot leach silicates in the water. It would take decades, centuries. It's like saying your aquarium glass leach silicates since glass in made of silicates too. It's an Urban legend circulating on the internet.
> 
> Michel.



Now this is interesting... because I have heard the connection between sand/silicates/diatoms as well and just took it as true with no examination. Another thing from the hobby that you just say "okay" and move on your way...

Of course, this is what makes many of those notions we repeat/circulate almost impervious to scrutiny.


I always had, in the back of my mind--- "I think its water from the tap that is actually contributing silicates and diatoms" ~not the substrate itself because of exactly the point you make in your post.


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## VintageTurquoise (Dec 23, 2018)

Discusluv said:


> Now this is interesting... because I have heard the connection between sand/silicates/diatoms as well and just took it as true with no examination. Another thing from the hobby that you just say "okay" and move on your way...
> 
> Of course, this is what makes many of those notions we repeat/circulate almost impervious to scrutiny.
> 
> ...


Thank you both. I was thinking the silica came from my tap water as well, because its GH is so high. But the tank has had the same kind of water for years and it used to run well without diatom. Now diatoms suddenly break out.....

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## Surf (Jun 13, 2017)

> Sand is made of silicates holded together with strong chemical bonds. 99,99% inert, no it cannot leach silicates in the water. It would take decades, centuries. It's like saying your aquarium glass leach silicates since glass in made of silicates too. It's an Urban legend circulating on the internet.


Not long ago I would have agreed with that statement. Most sand and glass is made of silica. Silicates however are not silica And they can behave very differently.

Sand has a lot of silica in it and it may or may not have silicates. Silica is mainly SiO2. Silicates are SiO1, SiO3, SiO4 and there are other forms of silicates. Silica (SiO2) is inert and not soluble in water Silicates in comparison are reactive and will bond with metal. Many forms of Silicates are not soluble but some are. Sodium silicate for example is somewhat water water soluble. Silicates will support diatom growth. Silica will not. 

IF you water is low in Silicates, any silicates in your sand should gradually get washed out over time with water changes. So a new tank 
can have silicate and diatoms problems but over time the silicate levels should drop and eventually the diatoms should die off. However if the primary source is your tap the problem may not get better.


https://en.wikipedia.org/wiki/Sodium_silicate

https://en.wikipedia.org/wiki/Silicon_dioxide

https://en.wikipedia.org/wiki/Silicate

I did a search and apparently phosphate removers also remove silicates from the water. Unfortunately you don't want to remove phosphates from your fertilizer. You might want to set up a bucket or water (enough for a water change and then put in a small filter made for a small aquarium and put phsphate remover in the filter. Put the filter in the bucket By the time you are ready for your regular weekly water chang you should have phosphate, silicate free water to put into your tank. Then add your fertilizer. If it works your diatom growth should slow and may stop. It is also possible that silicates might be reacting with your micros in your fertilizer or somehow slowing the growth of your plants. 



> I was thinking the silica came from my tap water as well, because its GH is so high. But the tank has had the same kind of water for years and it used to run well without diatom.


utility water chemistry can change over time. In the past your water may have had low silicate levels but now it may have a lot more. you might want to look around . maybe you can find a silicate test kit. If so test the water first before trying a phosphate remover.

I personally have not had a silicate problem but it might explain your problem. 

I looked through your other tread about your plant growth. You got good advice. That advice generally works for most people. But Have noticed a small number of people like you that still have problems. I am beginning to think that some of these problems might be nutrient overload or toxicity issue. This occurs when you have too much of one nutrient. And this nutrient make it very difficult for your plants to take in other nutrients. This like list some of the toxic symptoms. 

https://www.hydroponics.net/learn/deficiency_by_element.php

To elements on that list have been a concern of mine. Copper and Zinc. These are often used in pipes to reduce corrosion. But in the process of doing that they can also dissolve in the water Recently I saw a water quality report that showed zinc levels at 0.35 ppm when you only need about 0.02ppm in a fertilizer. My tap water has 0.05ppm of copper in it. About 5 times more than needed. I never used tap water in my aquarium. I have always used RO water. But the fertilizers I tried all had very very low levels of zinc and copper and that made it very difficult for me to get good consistent growth. 

I would try the the bucket with phosphate remover first. IF that doesn't work you may want to try softening your tap water by mixing it with RO water.


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## Discusluv (Dec 24, 2017)

Surf said:


> Not long ago I would have agreed with that statement. Most sand and glass is made of silica. Silicates however are not silica And they can behave very differently.
> 
> Sand has a lot of silica in it and it may or may not have silicates. Silica is mainly SiO2. Silicates are SiO1, SiO3, SiO4 and there are other forms of silicates. Silica (SiO2) is inert and not soluble in water Silicates in comparison are reactive and will bond with metal. Many forms of Silicates are not soluble but some are. Sodium silicate for example is somewhat water water soluble. Silicates will support diatom growth. Silica will not.
> 
> ...


Very informative, thank you.


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## OVT (Nov 29, 2011)

I use AS, CaribSea and tap water and I do get a lot of diatom, especially in new tanks. After about a year of not being able to control diatoms in one tank, I added an HOB with a packet of Seachem PhosGuard. The diatoms got under control in under 4 weeks. I started dosing P again about 2 weeks in. After the initial diatom infestation is under control, they rarely come back.

Besides diatoms, I see a lot of other algae in your tank and that is another issue where regular tank maintenance is step number 1 and checking your fertilization results is step number 2.


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## VintageTurquoise (Dec 23, 2018)

Surf said:


> Not long ago I would have agreed with that statement. Most sand and glass is made of silica. Silicates however are not silica And they can behave very differently.
> 
> Sand has a lot of silica in it and it may or may not have silicates. Silica is mainly SiO2. Silicates are SiO1, SiO3, SiO4 and there are other forms of silicates. Silica (SiO2) is inert and not soluble in water Silicates in comparison are reactive and will bond with metal. Many forms of Silicates are not soluble but some are. Sodium silicate for example is somewhat water water soluble. Silicates will support diatom growth. Silica will not.
> 
> ...


Thank you very much for the detailed comment. I appreciate that you actually read my previous posts (it was like an essay). 

I'll try using RO from now on. My question is, would using RO water in a long run "hurt" the RO filter system? I put it under the kitchen sink and replace it once every year. 



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## VintageTurquoise (Dec 23, 2018)

OVT said:


> I use AS, CaribSea and tap water and I do get a lot of diatom, especially in new tanks. After about a year of not being able to control diatoms in one tank, I added an HOB with a packet of Seachem PhosGuard. The diatoms got under control in under 4 weeks. I started dosing P again about 2 weeks in. After the initial diatom infestation is under control, they rarely come back.
> 
> Besides diatoms, I see a lot of other algae in your tank and that is another issue where regular tank maintenance is step number 1 and checking your fertilization results is step number 2.


I used Phosguard too but it does almost nothing to my tank. My tap water is basically liquid rock. 

Have you tried using RO water?

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## Surf (Jun 13, 2017)

An RO system is a lot like a car. You occasionally have to do maintenance. RO systems have sediment filter that periodically need to be replaced. They also have carbon filters to remove organics and chlorine (Chlorine can damage the RO filter. After these two filters (which is sometimes combined into one filter the water goes to the RO filter which separates the minerals from the water. Most of the minerals are discarded with a little bit of water through the sink drain. However some of the minerals will stay int eh filter and eventually plug it up. 

When the RO filter plugs up the mineral contents of the good water will go up or the amount of water produced per day will drop. A TDS meter makes it easy to verify if the mineral content of the RO water has changed. After the RO system the water sometimes goes through a DI filter ro remove even more numerals. DI filter is not really needed. It is optional in my opinion. Then the water goes into a small storage tank for storage. About once a year you should drain the storage tank and then verify the internal air bladder inside is properly inflated with air. The Air bladder forces water out of the tank when you fill your glass with water. 

How long the RO filter lasts will depend on how hard your water is and what types of minerals are present. The other filters should be replaced about 1once are year or as needed. Many manufactures recommend replacing the sediment and carbon filters about once every 6 months.

Two things you need to consider before purchasing a RO systems One is the size of your aquarium and the production rate. Most small under sink units only produce about 20 gallons a day. Your tanks is 75 gallon. That means your RO system will need 4 days to produce enough RO water to refill the tank. Now if you do a 50% water change once a week a 20 gallon unit would appear to be fine. But if something goes wrong and you need to do more frequent and lager water changes. you may not have enough.

The other thing you need to consider is how you are going to store 40 to 75 gallons of water. The storage tanks that come with most under sink RO unit only stores 1 to 2 gallons of water. Either you need are larger storage tank or you need to fill a large container with RO water and then pump it out into your tank during a water change. Air pressurized RO tanks capable of holding 80 gallon are available but they will not fit under a kitchen sink and will increase the cost of the installation. Storing water in a large bucket would workout you probably need a foot valve to turn off the flow of RO water once it gets full. And then you should consider using a small pump to pump the water from the storage tank to your aquarium.

I have a small aquarium so a small under sink unit and bucket is enough for my need. But for 75 gallons my RO system would be somewhat inconvienient.


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## VintageTurquoise (Dec 23, 2018)

Surf said:


> An RO system is a lot like a car. You occasionally have to do maintenance. RO systems have sediment filter that periodically need to be replaced. They also have carbon filters to remove organics and chlorine (Chlorine can damage the RO filter. After these two filters (which is sometimes combined into one filter the water goes to the RO filter which separates the minerals from the water. Most of the minerals are discarded with a little bit of water through the sink drain. However some of the minerals will stay int eh filter and eventually plug it up.
> 
> 
> 
> ...


Thank you for the informative comment. Keeping RO water in a bucket for water change seems to be a good choice. Also I think I'll do 50% RO and 50% tap to reduce the amount of RO water needed. 

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## KTimmons (Dec 9, 2021)

Sorry to resurrect an old thread, I am having this same issue.

Did you ever figure this out VintageTorquise?

About a year and a half ago I hard large sword plants overtaking my entire tank, everything started to be covered in diatoms and turn brown.

In frustration I removed all my plants and went to silk plants. After about a month of the silk plants I went back to real plants. The issue is happening again, diatoms creeping up my glass and decorations and major stunted growth on my plants. I am using Caribsea Peace River Gravel.


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