solidified sand bed

[madkeenreefer]

After a algea outbreak on my sand bed, I found when cleaning it up that the sand bed in the tank had totaly solidified.
Trying to break it up I soon realized the total mass of the sand was solid, only in places where the sand was over 3" deep was the sand not hardened.

I understand why this has happens but the question I have is as follows

? can I place new sand over the top of a solidified sandbed consiquence free?

SPS tank , dripping Kalk24/7 & Co2 reactor. 2" average sand bed.

TIA.

 

[DNA]

I don't think covering the problem with sand will solve it, but quite possibly cause new ones.
2" is hardly enough for the deep sand bed effect so a regular vacuum would be what I'd do.
You are likely to see massive amounts of detritus so doing it in several steps over time would be the right way go.

 

[jack.lai.83]

i would not cover the solid sand with more sand. i have found that if i lightly stir the surface as part of my regular maintenance that i have fewer clumps.

 

[xfactor1315]

Which sand did that? I have never had my sand clump up.

 

[bertoni]

You should be able to bury the clumped sand with fresh sand safely.

 

[sail33]

We've got direct conflict.

"I don't think covering the problem with sand will solve it, but quite possibly cause new ones."

"You should be able to bury the clumped sand with fresh sand safely. "

Please explain your position Cover or not cover and why.. Not looking to start a battle. Just wondering what experience led you to that opinion or is it considered fact ?

I ask because I've got some cyano starting. I plan to vac it out with a water change tomorrow but wonder if I could just bury it.

Seems to me that if I bury it, it's going to rot and cause other problems. Am I wrong ?

 

[bertoni]

I'm not sure what could go wrong, so I don't know to respond.

 

[sail33]

No problem Bertoni. I suspect that what ever is buried will decompose and raise numbers but I don't know that for a fact either. I'm going to follow my instincts and vac the cyano out.

I may have areas of sand that considered too deep. It's an uneven bed. some places 1/4 inch others near 3 inches. What I've read elsewhere warns about stiring sand too much as toxins can be released.

I'm just trying to get a better handle on what should be done.

OOOPS did I hi-jack the thread ? Sorry.

 

[bertoni]

I'd try to remove as much of the organic debris as possible. My original post was about burying solidified sand, so if your sand isn't solid as a rock, I definitely would work on some cleaning before adding more.

 

[madkeenreefer]

@ Jonathan, I was more leaning towards covering straight over the top of the algea as it is mostly coraline and some darkening of the sand like you would see on bleached rock as it ages.
For the folks whom replied to just stir or syphon this is impossible as the sand is not loose its rock hard and not in patches the whole 4x2` tank base is rock hard.
In one section of the tank where the sand is approx 3" I was able to break through the crust and even then I could not tear up the hardened sand around the small hole I chipped away with a screw driver.

Thanks again for all imput on this matter

 

[xfactor1315]

Any qlue what caused it to do that?

 

[Dougefresh35]

Dsb

Dsb

Heres a link to an article on DSB that explains the reason for the hardening! http://www.ronshimek.com/deep_sand_beds.html
Sounds like there wasnt enough or the right macro fauna in the sand bed!

 

[madkeenreefer]

Sounds like there wasnt enough or the right macro fauna in the sand bed!

It`s not as straight forward as just "macro Fauna" in the sand bed. The PH, Calcium & Alkalinity and pehaphs others play a key roll in the event.

See this thread:

Sand Solidifying
http://www.reefcentral.com/forums/sh...readid=1521274

A quote from Randy in this thread:

""It is not entirely clear whether sand bed hardening is a purely physical process involving calcium carbonate deposition (or other minerals) that cements grains together, or whether it is mediated by bacterial processes, but it does not always happen by any means.

It happens most frequently to new sand, and especially when the pH is high (as when using limewater). It happened to me when I first set up my first tank, but not when adding tanks to the existing system using the same type of sand. I would guess that higher alkalinity and calcium also contribute, as well as lower magnesium.

Often the effect disappears as tanks mature (the hard sections stay hard, but unclumped sand stays that way, and new sand won't as readily clump).

The addition of organisms (cucumbers, etc) seems to delay or stop the process as they keep it mixed up and perhaps break tiny links between grains before they become too established."


__________________
Randy Holmes-Farley"

 

[coralsnaked]

Sand beds do this naturally over time for 2 different reasons. But it can be accelerated by element levels in tank, principally Alk and is called early marine digenesis. Newer carbonate surfaces attract and deposit magnesium calcite. And sand that has only little bio-turbation causes the grains to stick together giving you the cement affect. However if the pH near the sand grains gets lower than 8.2 they start to dissolve, causing the local pH, Alk and Ca to rise causing a precipitation as they leave the solution, and the result is a binding together of the grains. In either case I have seen this more frequently when we utilize kaulk.

As far as what to do, there is really nothing else but to remove the hardened sand bed by whatever means possible. Personally I would clean the surface as much as possible and start to break it up and remove. Not sure what the results of just leaving it as is and continue to clean the surface using it like a bare bottom or an epoxy sand bed would be. But I don't think I would cover it up.

Over the years I have concluded that sand beds although desirable for different reasons become quite a management problem over time. I have moved all but 1 tank away from sand, a 10 yr old 8" deep sand sifting 650 gal FOWLR. It started out as a 4" deep bed and over the years I have slowly added another 4". Actually more than 4” as i also remove 1” periodically for maintainance.

Merry Skerry

 

[bertoni]

If the algae is mostly coralline, then just burying it is fine.