# Freshwater sand in a salt water aquarium



## 1200assassin (Jan 14, 2011)

Hi guys,

Ok so I know that using salt water sand in a fresh water aquarium is kind of a no no, but can you use fresh water sand in a salt water aquarium? I found a good price on some and am thinking of doing a 50 / 50 mix with some live or arogate sand. Will this cause a problem?


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## Will (Jul 24, 2008)

It won't help you keep your PH, Calcium, Alkilinity, etc in check like a good aragonite would. I would say it would be better to buy one bag now and then another when you can afford it than cheaping out in the long run. If you are looking to cut corners before the tanks even setup you'll be in trouble in salt keeping.


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## wtac (Mar 17, 2006)

To add to WH's points, silica sand is harder and has "sharper" edges. you have a greater risk of scratching the glass using a magnetic algae scarper, ie MagFloat. Also, sand sifting fish will develop oral "callouses" and will manifest into other issues. Seen enough of those in the early 90's when silica was the alternative to crushed coral.


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## 1200assassin (Jan 14, 2011)

Thanks for the info guys. It is really appreciated. But at $20 for a 50 pound bag I figured it was worth some research. $40 vs $120 means other toys I can buy such as a uv sterilizer or some nice frags or fish lol. I found that there are only 5 or 6 types of sand that are used in fresh/salt water aquariums? There is tons of info on what sand that you cant use when going from salt water to freshwater but I can not fins any info on going from freshwater to salt water. Thanks again for the info.


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## Chris S (Dec 19, 2007)

Also be careful, as some sands (depending on what they are made of) and even products like the flourish brand of plant substrates are often times magnetic, so even a larger worry for scratching your glass with a mag float =)


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## Will (Jul 24, 2008)

1200assassin said:


> Thanks for the info guys. It is really appreciated. But at $20 for a 50 pound bag I figured it was worth some research. $40 vs $120 means other toys I can buy such as a uv sterilizer or some nice frags or fish lol. I found that there are only 5 or 6 types of sand that are used in fresh/salt water aquariums? There is tons of info on what sand that you cant use when going from salt water to freshwater but I can not fins any info on going from freshwater to salt water. Thanks again for the info.


Few or none FW specific sands are truely suitible for SW, but many SW sands are suitible for certain FW fish/environments (species depending).


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## 1200assassin (Jan 14, 2011)

Is there a reason why?


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## solarz (Aug 31, 2010)

I'm still a newbie myself to marine aquariums, but are you going for a deep sand bed? If yes, then I wonder if you could put layer of silica sand on the bottom, and then top it with 2-3 inches of aragonite sand.


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## 1200assassin (Jan 14, 2011)

1 inch of silaite covered with 1 inch of arogate.


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## 1200assassin (Jan 14, 2011)

Thanks again for all the advice. I have had countless freshwater tanks and am setting up my first salt water tank and am trying to figure out the differences. Guess i'm a newbie again lol.


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## solarz (Aug 31, 2010)

1200assassin said:


> 1 inch of silaite covered with 1 inch of arogate.


looks like you're going with a shallow sand bed, in which case I think just 1 inch of aragonite is enough.

As I understand, you want either a DEEP (4"+) or a SHALLOW sand bed, but not something in between.


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## Will (Jul 24, 2008)

1200assassin said:


> Is there a reason why?


Yes. Because most FW sands are inert, and some are even designed to soften and lower PH, that would be very troublesome in a SW aquarium where the water parametres must be kept in specific ranges for success. But some FW fish habitats come from waters that are more similar to SW (without the high salinity) and so those fish tanks would benefit from having SW sands in them.

Also Deep sand beds would be more like 4" deep and some would argue that they arent truely effective until around 6" of depth.

$20 for 50lbs of silica isn't even the best price, I buy 100lbs for 10$ at this CAP BRICK in burlington. I know the price is tempting but be assured that in the long run it will even out as you will likely have to buy chemicals to dose the tank to maintain your PH, Calcium, Alkilinity, etc. Remember, Silica is inert, it does not alter the water at all, aragonite does, and helps keep those levels high enough.

Just use aragonite and use just aragonite. (and/or crushed coral, or crushed shell mix)

If for monetary reason you have to, add a bag at a time into the tank even after waters in, until you are at your desired level. But simply an inch or two will be sufficient.


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## 1200assassin (Jan 14, 2011)

Ok now im really confused. The guy that is selling it says that it will cause the ph to raise to 8.0 in a freshwater setup. He recommends it for cichlids which require the higher ph. 

That was actually the reason I was thinking about mixing it as my tap water is only 7.2 ph and i dont want to chem dose the tank to change the ph / kh. Does arogate sand also raise the ph? Basically that is my only goal as I really dont want to fight with chems at all when doing water changes if possible.


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## Will (Jul 24, 2008)

1200assassin said:


> Ok now im really confused. The guy that is selling it says that it will cause the ph to raise to 8.0 in a freshwater setup. He recommends it for cichlids which require the higher ph.
> 
> That was actually the reason I was thinking about mixing it as my tap water is only 7.2 ph and i dont want to chem dose the tank to change the ph / kh. Does arogate sand also raise the ph? Basically that is my only goal as I really dont want to fight with chems at all when doing water changes if possible.


Silica sand is inert. It does not change the water whatsoever.

Aragonite is not. In both FW and SW it changes the waters chemestry, which includes raising the PH.


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## Sunstar (Jul 29, 2008)

I am considering actually using some of my sand in my brackish tank with my ghost shrimps as they are nearly in full sea as it is. I plan to add a base rock, seed it with the tank bacteria then get the substraight out then add sand in in time. Chaeto is flourishing in my ghost shrimp tank O.O Silica also has other issues, isn't it? diatom algae loves it?


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## 1200assassin (Jan 14, 2011)

Pre-PS - Feel free to tell me to go search google for any of this info but i'm reading as fast as i can lol.

Thanks for the info. A way to naturally increase and maintain a higher ph and a good kh without having to add ph boost is all I am after. Aragonite sand it is. But having to equate Alkilinity is a new thing for me and I havent really done much reading on it.



Sunstar said:


> Silica also has other issues, isn't it? diatom algae loves it?


I've read the many debates on silica as being bad vs good for causing diatom algae (trace Silicates being absorbed into the water) and dont quite buy it. Algae bloom is a natural cause of excess nutrients in the water. I honestly believe that if you can find smooth silica it would take care of the bottom feeder issue and that it can be cultured with live sand to produce a live silica sand mix to make a more economical solution. Paying $120 for substrate is kind of rediculous imo. But of course its all theory at this point and i appreciate the feedback.



solarz said:


> looks like you're going with a shallow sand bed, in which case I think just 1 inch of aragonite is enough.
> 
> As I understand, you want either a DEEP (4"+) or a SHALLOW sand bed, but not something in between.





Will Hayward said:


> Also Deep sand beds would be more like 4" deep and some would argue that they arent truely effective until around 6" of depth.


Why more than 4" or only 1 inch. Are you refering to stuff like the Berlin vs the Jaubert's filtration method? I dont quite understand how not having roots (FW) in your substrate to combat gas (o2, ammonia, nitrate, nitrite) pockets or how the sand is used in the de-nitrification process.

Why would a deeper substrate be more beneficial in the biological filtration process. Would it be harder to eliminate the dead pockets of gas?



Will Hayward said:


> Silica sand is inert. It does not change the water whatsoever.
> 
> Aragonite is not. In both FW and SW it changes the waters chemestry, which includes raising the PH.


How much does Aragonite increase your ph/kh level and saltwater decrease your ph/kh level. Is there a snazzy online calc for it? I have a tap ph of 7.5-7.7 roughly. Best colour compare guesstimate. And am looking to maintain levels within 8.0 and 8.6 and am not sure what affects what in the ph kh scheme of things.

Thanks for the read


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## ozi (Aug 23, 2007)

What's the size of the tank? because you might not need as much sand as you think...


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## wtac (Mar 17, 2006)

ozi said:


> What's the size of the tank? because you might not need as much sand as you think...


True...3x17lb bags of dry Reef Floor Grade will be enough for a 90gal. I do recall the 40lb being way too much .


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## 1200assassin (Jan 14, 2011)

Its a 60g corner tank. I use a calc for sand depth and it came up with 55 pounds of sand for a 2 inch layer roughly. Need to do the calc again for the exact number.


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