Clumping sand...

[Robink]

Hi Randy, I'm having a problem with my sand sticking together. If I stick my hands in every week and check the sandbed I find the sand sticking together. Some of it breaks up and some of it actually gets hard like a rock.
Especially occurs around the rocks and frags that are on the sand bed.
Tank has been set up since the end of February this year. I use Fritz salt.
Parameters:
Sg; 1.026
Calc: 400-420
Alk: 8.5
Magnesium: 1520 (was higher, and I don't dose)
Nitrate: 2 ppm
Nitrite: 0
Phosphate: 0

 

[Randy Holmes-Farley]

Sand clumping happens mostly in newer systems. It's not entirely clear why this happens and happens more in newer tanks, but I suspect it is because things that get onto growing calcium carbonate surfaces and block further growth are not as high yet. Organics and phosphate, for example.

Clumping of sand may be purely abiotic, but may also be driven by biological processes.
Reduced precipitation can be attained with lower pH, alkalinity and to a much smaller extent, lower calcium, and higher magnesium, organics, and phosphate.

Fresh CaCO3 surfaces can be most prone to more precipitation. To break the cycle, it can be useful to stop dosing for a few days, let alk fall and precipitation stop, then restart with a much lower dose.

 

[Robink]

Sand clumping happens mostly in newer systems. It's not entirely clear why this happens and happens more in newer tanks, but I suspect it is because things that get onto growing calcium carbonate surfaces and block further growth are not as high yet. Organics and phosphate, for example.

Clumping of sand may be purely abiotic, but may also be driven by biological processes.
Reduced precipitation can be attained with lower pH, alkalinity and to a much smaller extent, lower calcium, and higher magnesium, organics, and phosphate.

Fresh CaCO3 surfaces can be most prone to more precipitation. To break the cycle, it can be useful to stop dosing for a few days, let alk fall and precipitation stop, then restart with a much lower dose.

Thank you.

 

[Randy Holmes-Farley]

You're welcome.

Happy reefing. :)

 

[DSmithZ28]

I have pretty severe clumping sand in my tank. Reading Randy's response above makes sense. I am using Kalkwasser in an AVAST stirrer and struggle with PH in this tank. (tank is 1-1/2 years old) It struggles to keep it at 7.8-7.9. It can go as low as 7.6 during the day when there is heavy traffic in the house. I took my ALK last night and noticed it was 9.3. PH was at 7.8 as usual. So my (2) questions is:

1) I am adding a CO2 reactor this week. Drilling a hole in the wall to run the input line to the reactor. This should solve my PH issues I hope. When this happens I should notice a drop on ALK and Cal correct? The PH over 8 should improve calcification and lower ALK and Cal? This should help reduce the participants because the corals should start consuming them faster. So I'm hoping that with higher PH my Alk and Cal will drop. LAst Cal was 460. I'm using 1 cup of Kalk in my reactor hooked to a Tunze ATO.

2) how in the world an I going to get the bricks of sand out? LOL I have read that because I don't have 4-6 inch deep sandbed that I shouldn't have any "surprises" under the sand when I disturb it to remove the "bricks". So should I remove a small percentage of the sand at a time to avoid a sand storm and any other issues? I plan to add some more sand to bring it back to the original height of 2-3 inches. just wondering if anyone has done this and what to expect.

 

[Martin Kuhn]

I don’t see a reason looking for a sandbed which is 2..3 inches thick. You could use this session also to reduce the layer thickness.
1..1,5 inches would be better from
My perspective.

I would not remove all of the crusted parts at once. This might disturb the important bacteria population and bring your tank in trouble. Also you might unleash some fouling zones within as thick sand beds.
I would do it in 3 .. 4 ‘stripes’ starting from one side of the tank. The following week you can continue with the next stripe and so on.

Another idea to get rid of crusted sand particles and anyhow a good idea is to use a cleaning crew. Sand dollars. Digging sea stars. Even better are v. Puellaris or V.Sexguttata which are really nice and good for reef tanks if they have a certain size. I personally would run each tank with a pair of them.