Clumping of the sand...

cginter · Jul 15, 2015

as the title says.. i went to go move some corals around the other day and noticed parts of the sand bed were rock hard, i haven't changed anything lately that i can think of. Tank was recently transferred over 4 months ago.
I am dosing Alk and Cal using dosers.
alk -9
cal-410
mg (1300-1450)
nitrate -(0-5)
am-0

its like the sandbed is soaking up the calcium and turning it into rock, NOT the entire depth of the SB but with in the first half inch. I thought either cal precipitation or some form a bacteria bonding the sand together (read that somewhere)

2.) reason for moving coarl was my forest fire digi started to look pale from the base up, but still showing small red polyps so i dont think its stn or rtn. picture shortly.

thanks.

cginter · Jul 15, 2015

ImageUploadedByREEF2REEF1436991220.718676.jpg

ImageUploadedByREEF2REEF1436991231.736274.jpg

As you can see the green is mostly gone in the coral and has turned white. It was one large piece but was broke into 3 pieces when I was placing Zoas down in the sand bed. All three pieces are showing the same signs. All other sps are fine. Could an alk spike cause this and the sand bed to clump?

Chameleon · Jul 17, 2015

I think you got it right when you said calcium precipitation. I have turned many sandbeds into rock. I find its easier to do with a calcium reactor than with two part but you can do it with either. I have always had increased cyano problems when the sand bed turns to rock.

Touring · Jul 17, 2015

Are you getting flow over the sand bed?

Randy Holmes-Farley · Jul 17, 2015

It is common for sand to experience hardening. It is most common in new sand and with high pH additives. It is probably calcium carbonate, perhaps enhanced by bacterial processes.

cginter · Jul 22, 2015

Randy Holmes-Farley said:
It is common for sand to experience hardening. It is most common in new sand and with high pH additives. It is probably calcium carbonate, perhaps enhanced by bacterial processes.

Well you hit the nail on the head. The sand was replaced in April and I am dosing 140ml/day of cal and alk.

As I continued to look for problems I did noticed that my power head quit working in my water storage bin. The water smelled funny and I found some mold spots on the top of the lid. (This was my top off water). So I'm thinking that may be part of my problem. Also I was getting a rough/hard layer of what looked like green algae growing on the sand and at the base of some of my Zoas which started to close up.

I discarded the water that smelled. Have the container a vinegar wash and rinsed out with ro water, then refilled to do a large water change today.

Would the top off water I was using cause some problems with my coral/sand bed? If so I believe I found the problem.