'Cooking' sand in the same method as LR?

[Stomkat]

I've been reading about sand beds for days after discovering my sand is what is causing my nitrate problems.

I figured it out after being told to cook my rocks. I removed 1/3 of my LR and cooked it for a month, and never got the phosphate/nitrate readings I was supposed to. My rock is dense and needs replaced, but that's a whole different subject (stupid newbie mistake). Other than being clogged with sand it is fine.

I had always read to not disturb the sand bed, so had never vacuumed it. I had found it odd at first, since I was a long time freshwater keeper and knew it was mandatory to vacuum the gravel to lower nitrates. But, with dust sized sand I figured it was feasible; I figured I'd end up siphoning the sand out. My tank has been running for 3 years with no vacuuming!!!

I have spent the last week vacuuming the sand, and removed ~10 lbs because I didn't want it as deep (only have ~1-2" now), removed all LR to the sump and QT tanks, placed egg crate so the pistol shrimp won't be able to bury the LR as much while digging.

All my reading is saying phosphates bind to the sand. Could you not 'cook' it as you do LR to get it to release the phosphates rather than just throwing it away? Wouldn't it be the same concept? Run it in a dark, covered container with heat and flow, changing the water weekly until there are no detectible phosphate/nitrate? I hate throwing things away if they can be recycled.

Currently reading about RDSB, going back and forth on whether or not I want one. I bought 3 - 15 gal containers for cooking rocks and could utilize one, got one out and ready, pulled out some sand, then started reading that ppl who have done it didn't see a significant change in nitrates. I was going to run it off my sump at the return, which would be after skimming and chaeto, but if it isn't going to do much there's no sense bothering with it.

That's what got me thinking about cooking the sand. Once the RDSB needs to be changed, I figured I'd just cook the used sand and reuse it. I'd have one running on the tank, one being revitalized. Take the used one off, rinse it really well and start cooking it. Thoughts?

 

[sirreal63]

Sand is so inexpensive most people just replace it. Instead of cooking it, consider using Lanthanum Chloride, which is a phosphate binder. (SeaKlear pool brand) It will pull out the po4 and will do it much faster than "cooking" it will. As for cooking it, the time, salt, water expense and electrical expense will probably add up to more than the value of tossing the sand and replacing it.

 

[moondoggy4]

Also maybe try using another phrase instead of cooking, not sure who will coin the better name. There was another failed cooking attempt that almost wiped out a family. Not trying to be over sensitive.

 

[billsreef]

Also maybe try using another phrase instead of cooking, not sure who will coin the better name. There was another failed cooking attempt that almost wiped out a family. Not trying to be over sensitive.

Don't know who coined that term, but your right, it's problematic ever since it's been used...people actually think it means to cook with heat on the stove

 

[Reefin' Dude]

"cooking" was coined by Bomber i believe, it might have been SeanT also. some of the other forums have tried to use purge instead.

most people find it easier to just replace the substrate, then to try and rejuvenate it.

Calcium carbonate (LR/sand)/Lanthanum Chloride/GFO are all phosphate binders. the strength of the bonds is what is different. GFO, lanthanum chloride will not strip phosphates from calcium carbonate unless the phosphates are freed off of the calcium carbonate matrix by some other force. either bacterial action or by dissolving of the calcium carbonate matrix itself. phosphates to calcium carbonate is a binding reaction, not an equilibrium reaction. it is going to happen. it will not undo itself just cause we want it to. luckily or unluckily for us bacteria will. this all depends on your thoughts on reef methodology.

if you siphon the detritus out of the substrate on a regular basis the substrate will "cook" itself just like LR will. the problem with a substrate is that it is closed on the bottom. the slow migration downward of phosphates through the substrate is stopped by the bottom of the tank. eventually the process clogs and the detritus just keeps building up and chocking the bacteria out of resources. the constant give and take between the bacteria and the calcium carbonate stops.

G~

 

[steve9]

Sugar sandbeds are well studied unlike most things that we debate
in these forums.
The most interesting finding was that they removed heavy metals
from the aquarium which may explain some tank crashes in dsb
tanks after 2 years.
I run a dsb in every tank i setup and always have nitrates under 1ppm
but feel it is wise to replace some of the bed yearly.
Just siphon a 1 foot area all the way to the glass out and use the washed
bagged stuff to replace it......works great never had any problems.
There are some great articles on sandbeds at ADVANCED AQUARIST.

 

[Reefin' Dude]

which is why all substrates should be replaced on a regular basis, or at the very least heavily cleaned of all detritus.

as for articles on sediments. i suggest people do their own research and not rely on the articles in the hobby literature. they tend to be biased and do not actually explain how eutrophication is handled in nature (which in a lot of cases it is not). for some eye opening reading look up eutrophication coral reefs. reads a lot like any thread on here about a tank crash.

G~

 

[Stomkat]

So basically the best bet is to just vacuum the sand, any sand that is siphoned out should just be kept out and replaced as needed with new since the phosphate bond isn't going to be broken easily.

I guess I'll recycle the sand in another way and use it for my gardening then. Thank you all for the explanation!

I don't understand why it's called "cooking" either.

I'll be reading all of the above mentioned articles/searches. I've always been a reader and if it helps me with reef/fishkeeping I'm all for it!

 

[Reefin' Dude]

bacteria are able to break the bond easily, but yes siphoning the substrate of detritus keeps the slow migration of phosphates down through the substrate going. bad things happen when the slow migration is clogged by detritus.

"cooking" gave the impression that it was fixing the LR, making it better.

it is not a good word. some use purging instead.

G~

 

[Fish Biscuit]

I would think with a pistol shrimp in the tank that your sandbed shouldn't be an issue since it's being constanly moved around. How old is your tank?

 

[megadeth72]

please dont use the term "cooking" someone almost got killed because they thought boiling rock was ok

 

[SantaMonica]

How about "nutrient nuking"

 

[dankreef]

Oh my god do not EVER boil anything out of your tank it can KILL YOU from the fumes! DO NOT BOIL ANYTHING EVER.

 

[S2minute]

I know what my DSB has been through over a 5+ year period. That's why i'm switching mine out now. My DSB is roughly 6" and the thing i did differently was to compartmentalize it into 12 sections. This way when i do change it, i switch out one compartment per month via a large water change. This makes it easier on me and the system. It also gives the benthic organisms time to repopulate the new section of DSB. I have to say this, i have observed this dsb of mine very closely. I never had to siphon mine ever. Detritus never built up on the surface. The benthic organisms constantly pull it under and eat it and the bac in the sand itself cycle it to Nitrogen gas. No3 undetectable. PO4 at .06 i was not happy with. I just started using lanthanum chloride and see how that works.

 

[burnah]

s2minute, have you already taken out one of your 12 sections? if so, how did it look/smell?

ho is the public opinion on chaning substrates in an algae/seagrass refugium? i know that they trap detritius, but shouldnt the algae/seagrass cope with that?

greetings martin

 

[S2minute]

'Cooking' sand in the same method as LR?

So far, since jan 13 i have replaced 4 compartments, one each month. I never had areas of black nor have i ever smelt and H2S while changing. Please note that the sand you use to replace should be rinsed as best you can. When South Down play sand was still easy to get from HD, i bought 1200 lbs of it. Upon initial rinsing, i saw that there was alot of dust and some small particals. I had to rinse batches x3 before the water became reasonably clear.
What you put in as new will still be there when you take it out. I would deff like to treat and reuse the old sand in the future, i just have to read up on the proper way to do it. The old sand was somewhat dirty but remember, i never had to siphon the surface because it never accumulated there. The scuds ate it and the other critters constantly pulled it under to eat it as well. The Bac in the sand bed also processes it with the end result being NO3 gas. If you would like a better understanding of what goes on in a DSB, there is a little book called "Sand Bed Secrets". Make for an interesting read.

 

[burnah]

well, if there is no black sand or detritus, do you see the need to change the sand at all? maybe extend the period to 2 months every compartment and see?

and what do you think about when plants take the nutrients via roots, will there be the need to change substrate?

martin

 

[S2minute]

To put it simply, the only concern i'd have with and old DSB is a buildup of toxic metals over time...or if that would even be any major concern. As long as your normal husbandry routines are good and your strict about it, i don't see any reason to replace a DSB. Unless you know it's been through some abuse in the past like mine was. The only thing i would do now is recharge it with a couple of Detritivore kits from various vendors like once or twice a year.

 

[S2minute]

'Cooking' sand in the same method as LR?

well, if there is no black sand or detritus, do you see the need to change the sand at all? maybe extend the period to 2 months every compartment and see?

and what do you think about when plants take the nutrients via roots, will there be the need to change substrate?

martin

I'm not quite sure i follow you on that. The only reason why i'm changing mine is because i know what happened to it in the past. The DSB was shielded from light by thick black plastic. Many times i removed portions of this plastic just to observe the conditions. Sometimes i did this with a magnifying glass. Try it sometime . Changing one compartment per month gives ample time for life to reestablish itself within the new sand and allows for minimum stress on the system. At the time, my DSB was 5+ years old.


You mean like growing Red Mangroves. Yes, that be a good thing to do if you can but i have not tried it myself. Just make sure the seedlings are adapted to salt water when you buy them.

 

[SantaMonica]

buildup of toxic metals over time

Algae loves to consume metals. You might even need to dose iron.