Sand Bed is Rock Hard

[tuggerlake26]

I'm noticing an issue that progressively us getting worse, despite trying to stir up my sand often.

My sand bed has hardened in the front of the tank. I am going to assume this is from precipitation when dosing. I use an auto doser with Red Sea alk and ca. Range is typically 8-9 for the alk and 410-450 for can (I know that's on the high end).

Any ideas if something else could be causing this? And how I could unharden the sand? I'm going to be moving the tank in a few months, and I'm concerned I don't be able to get the sand out.

 

[brandon429]

why dont we just remove it all in prep for the move, or change it out for completely pre rinsed sand now/ vs when you're trying to move. its much better to just remove it all and not mess with it

your tank doesnt needs it bacteria, it won't recycle. to pre rinse the new sand is for cloudless perfection, as we've done here seven years running

we should do this to your tank to get it ready for the move. regarding impaction, simply nobody has that happen here after our initial preps. I believe you can send a message to any entrant in this thread and zero will say theirs is impacted, and all are dosing alk supplements and calcium pretty much across the board:

 

[brandon429]

Official Sand Rinse and Tank Transfer thread

If you are reading this thread to cure a tank invasion from a link I sent you, we do not need to identify your type of invasion here we do not need you to test anything at anytime regarding nitrate, phosphate etc Above all, we do not need to see a microscope slide picture of your invasion at...

www.reef2reef.com

moving is a hassle with sand, youll need to just pre rinse it again (who wants a cloudy new tank at the new home?)

you can simply go bare bottom right now in prep. removing the sandbed won't cause a recycle if you copy works there (lowered light levels, lower your dosing inputs according to tests and less command by the bed dynamics after going bb)

you could then add pre rinsed prepped sand at the new home. You wouldnt want to skip pre rinsing, see how that causes variation over different tanks (to not pre rinse) but when pre rinsed for seven straight years the outcomes are perfection, that's a key detail on repeat. I once read in Randy's posts at rc that there's potentially an organic component allowing for this precip in the bed

and that organic component is exactly what we remove in rinsing out old beds. When pre rinsing new sand as we've done for fifty pages there's not organics being removed but we are removing flash silt components, who knows what role that plays

 

[FishyFishFish]

But that doesn’t answer the question as to what is causing it.

I’m following as I’m seeing the same thing.

 

[DivingTheWorld]

Sounds like precipitation. What’s your pH running at? I’ve seen precipitation with high pH. Are you using a CO2 scrubber or something to boost pH?

 

[dedragon]

Yep precip, I would leave it until the moved and then do what brandon said, might as well do all that work and get the room messy in the same day

 

[stevolough]

Sounds like precipitation. What’s your pH running at? I’ve seen precipitation with high pH. Are you using a CO2 scrubber or something to boost pH?

When it happened to me it was from over dosing. I should have realized I was using to much considering what I have for demand. Test and stop dosing and see how much your numbers fall and re adjust your dosing amounts. I now dose half the amount I was before.

 

[brandon429]

I recommend the work now because a work example in hand beats two in the bush

 

[Randy Holmes-Farley]

New sand that is missing a coating of phosphate/magnesium/organics/bacteria that all prevent precipitation of calcium carbonate, along with high pH and high alkalinity are the usual drivers of hardening sand. Old sand can also experience it.

Here's my usual recommendation:


1. Stop all efforts to boost pH.
2. Stop dosing alk for a bit and let it decline.
3. Reduce pH by switching to a low pH alk mix like sodium bicarbonate, or a calcium organic such as Tropic Marin All for Reef.
4. Ensure magnesium is normal to high.
5. Keep organics and phosphate on the high side.

After a few days of not dosing alk, restart slowly, adding additives to a very high flow area so it mixes in fast.

 

[tuggerlake26]

When it happened to me it was from over dosing. I should have realized I was using to much considering what I have for demand. Test and stop dosing and see how much your numbers fall and re adjust your dosing amounts. I now dose half the amount I was before.

I've been readjusting and my sand is still rock hard. Will it go back to normal or do I need to break it up? And if so, any recommendations on what to use?

 

[Randy Holmes-Farley]

I don't think the sand will un-harden in any short time frame. You might to replace some or all of it if being hard is a problem.

 

[brandon429]

I would like to see it changed out for pre rinsed sand, which removes silt fraction components as we've done for eight years in the link above, because we will get to see if it re hardens in the current chemistry settings of the tank.

We haven't had one instance of sandbed hardening in the entire thread, post- prep. What if silt = mortar

We certainly aren't having to worry about people's chemistry above, rinsed= win, so far in pattern.