Why not to use sand

[Freezekougra]

Any more questions, ask away![/QUOTE]

By stirring do you mean just stirring quickly or do I need to move all the decor and put them back in after stirring?

 

[MadRussian79]

i just spent the last hour searching through online chemistry journals and my university chem sites and cant find anything to support the OPs argument. I would be really intrigued to see which research papers his sister reads to provide evidence. Could the OP or his sister via himself please cite a source, purely out of scientific curiosity?

Basic chemistry text book, or look up industrial manufacture of sulfuric acid.
http://en.wikipedia.org/wiki/Sulfuric_acid. (This is the same way that sparging with CO2 lowers pH through the formation of carbonic acid.) However this is really not what will kill your fish as very little of the gas will go into solution most will be in the air. It can cause pH crash, they are rare and your tank would have to be in trouble first. What will kill your fish is the other noxious chemical released with the pocket of gas. Any number of nitrogenous compounds will be released into your water column. To put simply if you drink a cup full of toilet water from an un-flushed public toilet the water will be very acidic but the other stuff there is what will kill you.

I have 3M quartz sand in my tank and I usually syphon it like gravel but I turn my siphon down to low with a valve, this took some experimentation to get optimal flow. Plus I have a rake made from a CLEAN cat litter scoop and a peice of plastic pipe.

 

[Bderick67]

the part about sand 'trapping' nitrates/nitrites is not correct, but its more of a wording problem.

sand or gravel both can accumulate detritus which as I mentioned, is 'food' for oxidizing bacteria (the good kind for us).

but they don't accumulate the byproducts of bacterial metabolism directly.

the bacteria do their thing, and the byproduct of which is nitrates in the aquarium water..

the so called "food" for your oxidizing bactera is also a food for anaerobic bacteria, but the byproduct is hydrogen sulfate(bad news). Basically though if there is no waste trapped in the sand there is no problem. Hydrogen sulfide can not be produced without a carbon source(trapped waste).

Basic chemistry text book, or look up industrial manufacture of sulfuric acid..

So are you suggesting that the OP is correct and sulfuric acid is created in the aquarium?

 

[MadRussian79]

So are you suggesting that the OP is correct and sulfuric acid is created in the aquarium?

Technically yes it is but a very small amount. When the HS bubble rises to there surface there is some (very small) gas exchange at the edges of the bubble. Now if this bubble get pulled into you filter you will create much more H2SO4 and you can damage you bio filter as well.

This will happen with any medium be it sand or gravel if the material is left undisturbed for too long.

 

[12 Volt Man]

can someone clarify this:

when nitrate is reduced via bacteria back to nitrite, the byproduct released is nitrogen gas (I work in wastewater treatment this can occur at the bottom of settling tanks)

this is how denitritors work in an aquarium

is H2S also produced?

I am thinking you probably get both - nitrate reducing bacteria (which give off N2 gas) and sulphur reducing bacteria (which give off H2S (hydrogen sulphide)

N3 gas is harmless to us and our fish.

H2S of course, is highly toxic..

 

[Bderick67]

Technically yes it is but a very small amount. When the HS bubble rises to there surface there is some (very small) gas exchange at the edges of the bubble. Now if this bubble get pulled into you filter you will create much more H2SO4 and you can damage you bio filter as well.

This will happen with any medium be it sand or gravel if the material is left undisturbed for too long.

Interesting so there is actually oxidization of the H2S to create sulfuric acid?

can someone clarify this:

when nitrate is reduced via bacteria back to nitrite, the byproduct released is nitrogen gas (I work in wastewater treatment this can occur at the bottom of settling tanks)

this is how denitritors work in an aquarium

is H2S also produced?

I am thinking you probably get both - nitrate reducing bacteria (which give off N2 gas) and sulphur reducing bacteria (which give off H2S (hydrogen sulphide)

N3 gas is harmless to us and our fish.

H2S of course, is highly toxic..

Yes if there is a carbon source present you will get H2S

 

[12 Volt Man]

Interesting so there is actually oxidization of the HS to create sulfuric acid?

It is a reduction.

chem buffs will remember: LEO the Lion says GER

Lose Electrons Oxidize
Gain Electrons Reduce

 

[12 Volt Man]

Yes if there is a carbon source present you will get H2S

so your always going to get some then. any detritus will have proteins etc which are carbon based..

 

[MadRussian79]

I am thinking you probably get both - nitrate reducing bacteria (which give off N2 gas) and sulphur reducing bacteria (which give off H2S (hydrogen sulphide)

Yes, that's the long and short of it.

 

[Bderick67]

so your always going to get some then. any detritus will have proteins etc which are carbon based..

Probably true but it will need to be trapped in the sand where no oxygen can exist. So strirring the sand could actually cause more detritus to be trapped, possibly adding to the problem.