HELP!! Clumping of Sandbed!

[goodreef]

I've got a 5 inches deep Jaubert sandbed. Since I'm keeping mostly SPS, I've kept my dKH at 11, and Ca at 560ppm. This has worked quite well for me ... till yesterday!!!

In the 1.5 years that I've set up this tank, I've never disturbed the sandbed before. Yesterday, while re-arranging some corals, I noticed that my sandbed was hard like stone!!! Only the top 1/2 inch is "normal". This issue seems to be across the whole tank. This, I think, is due to the overly high dKH & Ca levels.

So far, everything seems to be OK ... water parameters are PERFECT, and corals & fishes are big, fat, and happy.

Can I assume that the sandbed is not breaking down NO3 now?
Is there anyway to break it down back into sand?
Should I leave it alone or tear it down?
Will it suddenly crash and kill my corals?
What should I do???

Worried ... sigh.

 

[3D-Reef]

There are two ways that the sand bed will clump into a rock.1) By the way the bacterial process works,the bacteria will secrete a type of 'glue' causing the sand to clump.2) The high calcium will chemically bond the sand together.
To tell the difference,take a piece of the sand/rock,and put it into a container of bleach.If it breaks back down into sand,Then it's the bacteria 'glueing' it together.If it doesn't break down then it's the high calcuim thats causing it.

 

[m2434]

dKH at 11, and Ca at 560ppm - I'd say your pushing the limits of saturation. It was just a matter of time. Have you checked your pumps? If it's an SPS tank I'm guessing you have a good amount of flow. Flow can sometimes help to prevent clumping. If a pump or two is not at max capacity, the decrease may have been enough to allow some settling at the sand bed. But, with that much ca and alk, you will always have precipitation... so, I would tend to buy this mechanism over the bacteria theory.

 

[goodreef]

Thanks ... Thinking back, I think it is due to calcium. One time, for few months, I had problems with sustaining my KH & Ca ... so I think I overdosed, and had precipitation issues. After few months, I finally managed to solve the issue, and has been having stable values since than. So, most likely, its a Ca issue.

I tried taking a clump of sand out, but I could NOT find the edge!! It seems as if the WHOLE bottom is one piece!!

Is there another solution besides bringing out a hammer and chisel?? Can I just leave it alone??

BTY, after lowering down my Ca & KH recently, my readings now is dKH = 10, Ca = 400.

(Note : the Ca reading in my previous post is 460, not 560!!)

 

[m2434]

It is better to break it up or remove it. Ca can percipitate as calcite or agaronite. The issue is that both are crystals, and once a crystal starts growing, it will be somewhat easy for it to sontinue to. The other option is magnessium, stronium and phosphate. All 3 can contaminate the surface of the crystal and make it more difficult for mor percipitates to "stick". Out of the three I would of course suggest magnessium :lol:

 

[goodreef]

Yea ... I REALLY pumped in lots of Mg ... Now, Mg at 1500ppm, and stable for months. So, I'm not so worried about additional precipitation.

I'm thinking ... if the sand has now become rock, would I get issues with hydrogen sulphide later??

If not, I'm prone to just leave it as that!!!

Any other concerns besides precipitation??

 

[m2434]

Could be a problem. I would at least break it up if possible. I wouldn't raise mg any more.