Sand clumping together???!!

[jefferzbooboo]

I have a 55 gallon tank with a 2 inch sand bad. My sand is clumping up in sizes from a quarter to a cigarette pack and there fairly hard.
The clumps turn black and when I break them apart you can see where the water turns green.
My water tests show pH 8.3, nitrite 0, nitrate 0.2, calcium 450, phosphates not detectable. I ran a SG of 1.0124. I thought the tests were off, but I've bought 3 different types of kits and took a sample into my 2 differnt LFS and they're all consistant
I have about 15 nassarius snails in the sand bed and a Diamond Watchman also.
I've continued to break the clumps apart, but its a persistant problem, does anyone have any idea what would be causing this or what can be done to prevent it?

[m2434]

Are you dosing kalk?

It's turning to limestone. Actually aragonite sand is essentially limestone already, but your getting excess precipitation which is making it stick together. I'd recommend reading some Reefkeeping magazine articles on reef chemistry. There are many possible reasons this is happening.

[m2434]

also, 1.0124 is way low, I don't think this has anything to do with the problem, but I would raise this anyway.

[jefferzbooboo]

The only thing I'm dosing is Kent marine Liquid Calcium. My sg is 1.024, I did a typo, sorry.

[m2434]

What about alk and mag?

I'd start here:

http://reefkeeping.com/issues/2005-07/rhf/index.php

http://reefkeeping.com/issues/2006-06/rhf/index.php

http://www.advancedaquarist.com/2002/3/chemistry

http://reefkeeping.com/issues/2002-0...ture/index.php

[jefferzbooboo]

I got an alkalinity kit from a friend, and my rates were off the chart, I read lots of things on raising it, but how do I lower it? I don't dose for it, so I have a hard time understanding why it would be high.

[m2434]

If you don't dose for it, you should not be off the charts. I would try another kit.

The following chemicals can add to alkalinity
bicarbonate, carbonate, borate, silicate, magnesium monohydroxylate, hydroxide, phosphate

Is there a chance any are getting into your system somehow? Is there an alk component to Kent ca supplement?

At risk of sounding redundant, I would try another kit.

[cd77]

I'm having a similar problem as well. Don't know if it will help, but here is the response I got:

[Rosseau]

It is possible that worms are generating these aggregates.

As they ingest and filter the sand through their bodies they often come out the other end in clods.

I would suggest that.

I have similar aggregates to those you are describing created from stray sand which gets caught in the worm as seen below. I don't think it actively filters sand yet some gets caught inside of it and it must get it out.

This picture doesn't show the aggregate, I have one somewhere...

[Rosseau]

The correct term is "casts" instead of "clods".

[cd77]

Originally posted by Rosseau
Still fighting entropy.

Good luck with that Great sig!

[m2434]

Sand clumps because of calcium precipitation... Your calcium and alk arn't balanced. So you get calcium carbonate precipitation mixed in with the sand and it "sticks together".

The question is why isn't jefferzbooboo parameters balanced?
I don't know anything about kent calcium, but I'm guessing it's not a balanced suplement - So I think there is an easy solution here...


For others having this problem try readin this -
http://www.reefkeeping.com/issues/2004-12/rhf/index.php

Good luck with that entropy

[m2434]

Found Kent directions -certainly does not seem to be balanced... also, in this case I think sand fits under the category "other sensitive system equipment"

Directions:
Add ¼ to 1 teaspoon (1/4 to 1 capful or 1.25 to 5 ml) per 50 gallons (190 l) of tank capacity each day, based on animal load. Since animals use calcium, and gallons do not, regular testing of calcium level by a good calcium test kit (HachTM brand is recommended) is advised. Adjust amount of addition of the product to achieve a calcium level of about 400 mg/l. A higher level may result in rapid calcium compound precipitation and deposits which can possibly be destructive to pumps and other sensitive system equipment. It is recommended that you regularly check impellers and other delicate equipment for calcium deposits if you run higher (above 400 mg/l) system calcium levels! For best results adjust system KH to 8 to 10 dKH with Superbuffer-dKH or Marine Aquarium pH Buffer.

[Frick-n-Frags]

sand clumps because of bacterial cementation, and those are anaerobic areas that have been sealed away from oxygen.

there is not enough flow + concentration to precipitate Ca-carb deep in the sand. precipitation would be like at pump impellers and heater glass or high concentrated dosing areas if at all.(ie snowstorms etc)

[Rosseau]

Thanks for the kind words with the entropy - I need all the help I can get.

[m2434]

Originally posted by Frick-n-Frags
sand clumps because of bacterial cementation, and those are anaerobic areas that have been sealed away from oxygen.

there is not enough flow + concentration to precipitate Ca-carb deep in the sand. precipitation would be like at pump impellers and heater glass or high concentrated dosing areas if at all.(ie snowstorms etc)

Well, his sand bed is only 2" so it shouldn't be anaerobic. Also, really any heterotroph bacteria can do this. Regardless, the cause is still high concentrations of calcium ions and/or decreased magnesium concentrations. If jefferzbooboo is dosing calcium, but not ma or alk, then there will certainly be clumping due to precipitation. Even if bacterial mechanisms are involved, it's still precipitation (and would happen anyway without bacteria at these levels of ca).

[jefferzbooboo]

So if the bacteria was clumping it together, how would I solve that problem? I'm not doubting yout m2434, I'm getting a Kent Marine 2 part buffer from my LFS and testing kits for MA and ALK, they had to order the buffer and it will be here soon, I just want all options to try if it doesn't work.

[Rosseau]

You say that when you break apart these clumps green water comes out? To me, this suggests some type of biological modification.

Do you have access to pictures of your sand?

[Frick-n-Frags]

after the bacteria clumps and seals a chunk together, the inside is anaerobic. ie, when you split open your little geode you see black and green and it stinks

also, those parameters aren't even close to the precipitation point. once again, you fail to acknowledge that there would be initial precipitation at concentration and catalyst points, NOT under a lowflow, and I might add, more acidic region under the sand. that would be the last place for precipitation. also, exposed surfaces are quickly smothered by bacteria and lose all buffering influence.

A biologically active tank could make this happen faster than a leaner running one, but it will happen eventually no matter what, because that's what happens. Even large old-school aragonite would clump like that.

just like anything else, over time, there is a constant evolving, and unless you put in periodic disruptions, the system will evolve towards some new ends. you will have to figure out if you want to keep the thing stirred like an SSB or let it age out like a standard un-disturbed DSB and replace it.

you are sort of in limbo IMO: not a DSB and not an SSB, so I don't know how that will all play out for you.


edit: high alk will precipitate Ca out better than low alk. so running low alk will enable pretty high ca levels without precipitation

ps: this is why I am not entirely in favor of the reef chemistry quick cheat sheets idea of other threads. Life got way easier after I worked my way through all the chem info here at RC, and I mean pretty much all of it. now a quick cheat sheet is great because I know what I'm calculating and why.

[m2434]

Originally posted by Frick-n-Frags
after the bacteria clumps and seals a chunk together, the inside is anaerobic. ie, when you split open your little geode you see black and green and it stinks

also, those parameters aren't even close to the precipitation point. once again, you fail to acknowledge that there would be initial precipitation at concentration and catalyst points, NOT under a lowflow, and I might add, more acidic region under the sand. that would be the last place for precipitation. also, exposed surfaces are quickly smothered by bacteria and lose all buffering influence.

A biologically active tank could make this happen faster than a leaner running one, but it will happen eventually no matter what, because that's what happens. Even large old-school aragonite would clump like that.

just like anything else, over time, there is a constant evolving, and unless you put in periodic disruptions, the system will evolve towards some new ends. you will have to figure out if you want to keep the thing stirred like an SSB or let it age out like a standard un-disturbed DSB and replace it.

you are sort of in limbo IMO: not a DSB and not an SSB, so I don't know how that will all play out for you.


edit: high alk will precipitate Ca out better than low alk. so running low alk will enable pretty high ca levels without precipitation

ps: this is why I am not entirely in favor of the reef chemistry quick cheat sheets idea of other threads. Life got way easier after I worked my way through all the chem info here at RC, and I mean pretty much all of it. now a quick cheat sheet is great because I know what I'm calculating and why.

Your making this a bit too complicated...

The reason excess calcium causes this is simple. Agronite is a calcium carbonate crystal surface. When excess calcium "bumps" into a calcite (calcium carbonate) crystal, it sticks to it and the crystal grows... The anaerobic area has nothing to do with it.

Creith snails and other sand sifters work to break this apart.

[Frick-n-Frags]

I wouldn't even know where to start, except to say that you are really missing the big picture here.
whatever you are talking about isn't the realities of the reeftank substrate, more like a chemlab experiment.......

[Rosseau]

I will concede that in general calcium acts as a flocculant and sodium as a dispersant of soils/sediments.

[m2434]

Originally posted by Frick-n-Frags
I wouldn't even know where to start, except to say that you are really missing the big picture here.
whatever you are talking about isn't the realities of the reeftank substrate, more like a chemlab experiment.......

No chem lab... I'm just going with occam's razor using basic well established facts...

The simplest explanation for sand clumping is overdosing ca. Agaronite, is a calcium carbonate crystal, similar to calcite (limestone). If you have a clean crystal surface, calcium will, as Rosseau put it, flocculate and the agaronite crystal will grow. I believe this happened here because instead of monitoring both ca and alk, and trying to add them both in balanced moderation, ca was added and combined with the carbonate forming CaCO3 and crystallized into more agaronite. Additionally, jefferzbooboo said only ca was dosed, so there was not enough mg to disrupt the agaronite surface allowing rapid crystallization. The ca levels dropped and more was added and the clumps grew...
(So in other words, there was sufficient ca to force both ca and CO3-- out of solution - this is enhanced due to a clean crystaline surface).

The worm cast idea is reasonable, but it seems somewhat unlikely that you would get “cigarette pack” sized clumps from this.

The problem with the bacterial induced sedimentation is that it occurs because organic molecules such as proteins and glycoproteins (and others) bind to the agaronite surface and prevent phosphates and magnesium from binding. Because, phosphates and magnesium inhibit the growth of the agaronite crystal, there is now no inhibition of crystallization.

However, the theory is not very well established, but there is evidence that inhibiting protein synthesis does decrease calcification considerably. Regardless, there still needs to be sufficient ca,so overdosing ca, and under-dosing mg, is still the real issue. In this case, mg isn't being dosed, so it's effect will not be inhibited much anyway – because there isn't much of it anyway!

Frick-n-Frags, you seem to understand a lot of important concepts, but I think you maybe dont't quite get the concept of crystallization...

[Frick-n-Frags]

Originally posted by m2434
If you have a clean crystal surface,

=chem lab experiment.

Hey, tell him whatever you want, it's not my tank.


to the original thread starter:

I would think about changing the depth of the sandbed to deeper, or make sure it is sifted all the way to the bottom.

I would also think about making sure I have accurate: pH, alk, Ca tests too.

[Rosseau]

I never read the "cigarette pack" sized part of it all in the beginning........ I think you would notice an invert making something that big in there!.. yikes.