Sanbed solid like cement

[acabgd]

I'm running a small 7G nano and I've been having some nitrate issues lately, probably due to a hermit duying.

I've been trying to increase my maintenance since and while cleaning the sandbed I noticed a part of it solidified completely, it's as hard as cement. I tried "breaking" it with the turkey baster but I simply couldn't, that's how hard it is.

The area is small, maybe 2-3 inches across, as if something spilled over the top of the sand rendering it solid.

Any idea why this has happened and if I should still break this "block" of sand?

[kissman]

Sounds like you dont have enough critters to keep the sand bed stirred. This is likely part of your nitrate issuse. The sandbed cant convert the nitrates to allow them to escape as a gas and rise to the surface to exit tank

[ajcanale]

Do you dose two part alk and calcium? or just water changes?

[mtcoins123]

I would gently remove the "chunk" trying not to cause a cloud of sand dust and replce it with cleaned sand.

[TealCobra]

I have had this same problem many times in the past in different tanks. I would definitely lean towards not enough critters in the sandbed to keep it agitated. I would like to hear more about the science behind what causes the solidification though. As previously stated, remove what you can, break it up and put it back in your tank. I'm about to break down and order some stuff from IPSF to help out in our new 120g. FWIW, I have used 2 part DIY Ca/Alk in all of these tanks.

[TealCobra]

Well after a quick refresher on Dr. Ron's website I found this.

"Rapid bacterial growth rates only occur without competition for space or nutrients. As the bacterial populations fill in all the open spaces growth slows and may stop altogether. Some bacteria also secrete a exterior covering called a "glycocalyx." These glycocalices are made of a hard sugar-like material similar in consistency to rock candy. Rapid bacterial growth may produce so enough of this material to glue sediments together. These sediment lumps may be glued so tightly together that hammering is needed to break them apart. In much reef literature, these lumps are said to be caused by calcium carbonate or calcium phosphate precipitation. Such mineral precipitation is rare; if a small sediment lump is placed in a weak solution of household chlorine bleach, it breaks down to the component sediment grains in a short time. If the lumps were formed from the calcium salts, they would not dissociate in the bleach.

Lump formation is a disaster for the biological filter. The lumps restrict water flow and trap organic material where it can rot. Additionally, lump formation shuts down the biological filter by covering the bacteria and preventing them from metabolizing nutrients. This, in turn, causes the tank nutrient levels to skyrocket.

Fortunately, prevention of sediment clumping and the simultaneous maintenance of optimal biological filter operation is easily done by the establishment of a healthy and diverse sediment dwelling fauna, or "infauna." The infauna, so-called as the FAUNA lives IN the sediments, is a very diverse array group of wonder-working organisms. Unfortunately, they are small, and are not particularly attractive. Like Rodney Dangerfield, "They don't get no respect." And, that is a pity, as they do most of the work in keeping any reef tank functional."

http://www.ronshimek.com/deep_sand_beds.html

[Yogre]

Interesting. I've noticed since I've been dosing vinegar an increase in sandbed clumping. I figured it was something bacterial, but until now didn't know the mechanism.

[acabgd]

Originally Posted by ajcanale

Do you dose two part alk and calcium? or just water changes?

I dose calcium, but the solid part doesn't have any particular coloration. If it was indeed calcium precipitation, shouldn't it be white?

This was a very interesting read with great answers, now I know a lot more. I would say that first and foremost I have too little sandsifting critters, snails or whatever. Must increase that significantly.

Thanks again to all.

[spollock818]

Whats your KH like? Have you had any high spikes? I notice when I overdose and raise my KH to like 10, my sand hardens and I have to break it up. Just saying

[NanoAquatic]

Put some empty shells and some hermit crabs to soften out the sand. As for the hardened one, throw it out and put some new ones in o.O

[acabgd]

Thanks guys. Got me some new snails (turbos) today, some 6-7 of them, let's see if they will work overtime

[rrasco]

Turbos don't stir the sand bed...

[TealCobra]

Originally Posted by rrasco

Turbos don't stir the sand bed...

Beat me to it. TS, you should consider Cerith snails, some (don't go overboard) Nassarius vibex snails to help aerate your sand bed.

[Reefin' Dude]

or it could be from the increase in bacterial activity causing a drop in the pH in the substrate causing the calcium carbonate structure to break down, then reform when reaching higher pH areas in the substrate. at which point causing a shut down of any so called benefit of the substrate.

G~

[acabgd]

Well if turbos won't do the job then it's time to change my LFS as well as I explained the problem and presto - he handed me a bag of snails...

[TealCobra]

I'd say they didn't really address the problem correctly.

[DLANDINO]

Curious if you dose Kalk to your system and if so, what is the delivery method?

[bobears03]

I have found it depends on what your substrate is and what you levels have. How high is your alk and cal? What kind of substrate are you using? Argonite will bind at high calcium an alk levels. I've had bricks in my tank and it has nothing to do with bacteria.

[acabgd]

For alkalinity I dose Kent Superbuffer, but usually it's not really needed if Mg and Ca levels are okay. I dose only Tropic Marin Bio-Calcium daily, Mg as needed but very rarely (once a month, sometimes twice as neded after measuring).

My levels dropped with this unfortunate event that I've had and Alk was down to 6.5, Ca was 200 (!) and Mg was 1200. Slowly raised everything back to normal and only then noticed this solid patch.

[reefrubble]

My sand bed got like concrete , because I was dosing to high of a conconcentration of alk (soda ash ) . I had to remove everything , and replace the old sand bed , with new live sand .

http://www.reefcentral.com/forums/sh....php?t=2192868