Could high salinity cause my sandbed to harden?

-Logzor · Jul 27, 2012

About a year ago I accidentally dumped over 600+ mL of two-part alkalinity solution into my reef, which proceeded to turn solid white for two days (thankfully nothing was lost). Shortly afterward I noticed most of my sandbed hardened into big chunks. About 4 months ago I replaced the sand. Now it has hardened again! I've been working on lowering my salinity, which is now at around 1.028. It's been working down from 1.030++ (bad refractometer calibration solution).

Could the high salinity cause this problem?

mainereefer · Jul 27, 2012

high calcium! or not enough magnesium (without the mg corals cant use calcium)

psionicdragon · Jul 27, 2012

Or lack of movement in the bed.

AJreefs · Jul 28, 2012

mainereefer said:
high calcium! or not enough magnesium (without the mg corals cant use calcium)

_bam_

mainereefer is spot on

mcarroll · Jul 29, 2012

Yeah, typically it's dosing related, not salinity related, but I think pH is the parameter that plays into precipitation (which is what's gluing your sand together).

How are your Ca, Alk and Mg numbers? pH? And now vs when salinity was at it's highest? In light of the high salinity I'm guessing all your numbers "should" be pretty high.

Also what/how much/how often do you dose on this tank?

-Matt

specvjeff · Jul 29, 2012

Alk is what causes calcium to precipitate. That's why you don't dose two part at the same time and when your alk is really high the calcium is low. Magnesium allows the calcium to maintain at a higher level. Bad refractometer calibration solution? You are suppose to calibrate it with freshwater. Btw you can bring your salinity down to 1.025 rather quickly. It's going up really quickly that can cause problems. As far as the solid substrate, I'm not 100% sure what's causing it but after the amount of time that's passed since the accident I doubt it's the cause. What are all of your levels at right now? Calcium, alkalinity, magnesium, ph, and nitrate.

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reeferman · Jul 29, 2012

you are not supposed to calibrate with fresh water.always calibrate with calibration fluid.fresh water calibration can be way off.always calibrate everything within the range you are using it for.

-Logzor · Jul 29, 2012

Alkalinity has been pretty solid at around 9-10. Ca did go up near 500 a few times, typically it's around 420. Mg is typically around 1300 but it has dipped down to the 1100 range as of late.

Sounds like it might be an issue with my Mg.

specvjeff · Jul 29, 2012

How can good rodi water be way off?

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myzislow · Jul 29, 2012

specvjeff said:
How can good rodi water be way off?

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calibrating with rodi water may work well for you but it's commonplace to calibrate with a standard of 35 ppt as that is where most of our systems are run, or there about. Doesn't make a lot of sense to calibrate a refractometer that is intended to be used with saltwater using an RODI standard. It is pretty far off on the scale in relation to the range in which we use the instrument IMO.

specvjeff · Jul 30, 2012

I'm going to buy a second refractometer and calibrate it with 35 ppt solution and also continue using the one I calibrate with rodi and see if there is any difference.

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