Has your sand solidified?

I think it has something to do with low PH or useing a cal reactor and escaping co2 into the tank? Just what I read somewhere.....but Ive read so much I think ive heard many opinions on everything. : )

Jay

 

Nope mine seems to stay loose as a goose!

 

That's just about the whole story in a DSB all the acids build up as the waste sulfides are very acidic and when heats up and migrates to the higher better oxygenated areas of the sand where it then it comes into contact with the more alkaline harder carbonate waters above then it will crust over and fuse just as concrete does and then it's pretty much the first indicator the whole thing is about to head south really fast.. Its been the major limitations of a DSB for 40 yrs.. Herbert Axlerodd and Spotte wrote about it first in 1970 was the first I read a bout it when we all where looking for the perfect natural system..

 

Chemical Solidification

Many chemical reactions don't happen like the reef literature says it does once the sandbed is established and the sand is coated with bacteria and organics. For instance, everyone told you that you need to use aragonite substrates because it will dissolve in lower pH situations and buffer your water. As soon as the substrate becomes coated with bacterial biofilms, almost all of the chemical reactions that occur are controlled by bacteria. Actually, that's a good thing....otherwise you would need to add more sand to your system every couple of months. However, on newer sandbeds that are not fully populated with bacteria, organics, etc., these chemical reactions can occur and cause solidification.

While sulphide reactions can cause this to a certain degree, this really only occurs in a completely overwhelmed DSB (too much organics, not enough sand stirers, not enough Oxygenation, etc.) or a fairly new sandbed. For instance, Hydrogen sulphide zones are formed and then removed on a regular basis. The by-product of anaerobic Sulphate Reducing Bacteria (SRB's) is our nemesis Hydrogen sulphide. SRB's are limited by the amount of organics in the DSB as there will always be plenty of sulphate. (In other words, if you overload your DSB with organics, these guys can reproduce and produce a lot of H2S). In a system that is not overwhelmed and has plenty of bioturbators, the Hydrogen sulphide is harlmlessly converted by aerobic SOB's (Sulphide Oxidizing Bacteria) before it can even become a problem. The chemical reactions don't usually occur in an established sandbed because bacteria don't allow them to occur.

There's a number of things that can cause this but the cause of most solidification of a DSB is an accidental overdose of Kalkwasser or buffers and too low of a level of Magnesium. This usually is from people trying to push their Kalk or two-parters too much. This causes the alkalinity to go up too high causing Calcium to fall out of solution. The resulting calcite (Calcium carbonate) that forms locks the sandbed particles together like a brick. Obviously, this is only occuring at the surface of the sandbed. Depending on the size of the overdose (and resultant precipitation), this might just make some crystals stick together. If you have a large precipitation, then you can create a crust on the surface of the sand thick enough that bioturbators (sand-stirrers) cannot break through. This can set up a chain reaction that can turn your entire DSB into a brick and it is hard to to stop it once it starts. (I.e. Oxygenated water cannot get into the sandbed anymore, bacteria continue with their respiration, all of the Oxygen gets used up, CO2 increases, bacteria (and their biofilms) die en masse, pH drops, some chemical reactions do take place causing more fusing, ......end result is a sandbed brick.

If you keep a DSB, it is important for you to have an battery backup airpump. Bacteria don't stop respiration just because the power is out. You should also have something to keep the water moving over the sandbed (even if it's nothing beyond your hand moving water). A long power outage can cause dissolved Oxygen to drop, CO2 to increase, bacteria to die.....sandbed brick.

Biological Solidification

Some bacteria create a substance called glycocalyx which is like a glue to sand particles. glycocalyx sediments - Google Search

Additionally, some worms can cause problems.

The Worms Crawl In… by Ronald L. Shimek, Ph.D. - Reefkeeping.com

OK, how do you stop this from happening?

• First, never have a newer sandbed. ;D Ok, since this is not really possible, be aware that overdoses of Alkalinity/Calcium with high pH and low Magnesium can cause some major problems for you. (Test your Magnesium level).
• If you use Kalk, don't drip faster than you should to get more Calcium. It's a reciped for disaster. (Besides, corals only need 380ppt...trying to go to 500 will just cause precipitation.)
• Prevent organics from building up in the sandbed. This means you shouldn't cure LR over a brand new sandbed, should have good flow in your tank to prevent food and detritus from settling in the bed, don't overstock your tank, don't overfeed your tank.
• Have plenty of sandstirrers to continually bring Oxygenated water into the aerobic zone, break down excess food, etc.
• Watch for excess growth of the worms I showed above.
• Periodically, use a spoon and check for sandbed chunks in the UPPER layer of sand.
• Raise your LR on pylons above the sandbed to prevent anaerobic zones.

 

Yup, it's a chain reaction and it is hard to stop the reaction. Then write into a particular doctor and he will scold you for not setting up EXACTLY like he told you (even if you followed his instructions to the T). :

Has Colleen complained???;D

 

It's more to it then this.. Bottom line is at the end of the day all septic tanks fill up and fail. Nuff said by me about harening and crusted sand . Its not a concern of mine. As for the Dr LOL!!!!!!!!!!

 

LOL!!! Tell us how you really feel about DSB's.

I personally don't have a problem with people having DSB's. I just wish they operated like they were originally advertised and that couldn't be further from the truth.

BTW, my DSB in my acrylic mantis tank nuked every living thing in it. I had limpits, stomatella snails, strombus snails, chitons, hundreds of mysis, ampipods, copepods, bristleworms, both red and white forams, etc. I'm a guardian for a troubled teen and even though I've told him time and again to keep his hands out of my tanks, he decided the DSB looked dirty. He put a wooden spoon in there to stir the sand and hit a H2S zone. Instant death for the entire tank. (I'm getting mad again just typing this because these animals were the descendants of my very first tank....I've never bought a replacement clean up crew in my life).

 

I just know the DSB snake for what it is I have over the last 37 yrs tried and retried them in every fashion that one can think of.. Its just has to happen its a little glass box of water and nothing about 4,000 ft can consume methane and the sulfides will move up to the sand and when sulfide sludge and lime meet up you get carbonic gas LOL.. Then the advertising of the magic sand size only made it worse.

The good Dr/ had more then a few to nuke as well LOL only he could write his off. he had nothing new and all this crap about Ing or Eng ?? people overlooked the fact he was talking about U/G's in his Discus tanks back in the mid Fifties. .
The best one I ever ran was about 3 inches of old Ga. clay cat litter then capped with about 3 inches of aragnoite like custom sea floor that one ran about 3 almost 4 yrs. I never had a lot of clumping of the sand myself as I fed my animals very little weekly. But I found it limiting in the amount of bio load it could support.. But Portland cement is made of just about every element we run in out tanks just powered alot finer in the grain size..Just add water LOL

 

Are you saying that my sand is positivley going to harden? I haven't been around as long as you guys but I've never expierienced this phenomanom- are my critters wandering through the sand bed sifting in vain? Enquiring minds want to know!

 

Well thats one thing I can say I have not encountered yet!
Q