does oolitic sand really work?

[Wiz]

Hey guys, so I decided to add a 30g dedicated dsb refugium to my system after phosphates started climbing. I read and read, finally coming across a fantastic article by ron shimek. http://www.ronshimek.com/deep_sand_beds.html. so I modeled my refugium on his instruction. 20+ years can't be wrong, right?. In this article he specifically list the prime grain size for variety of sand life to be .05-.2 mm. It took me a long time to find sand that fine. But I wanted it to be perfect. So I settled on the finest I could find. Marine white #0. the grain size is .1-.5 mm. Which is actually a bit larger than recommended. The sand was so fine it just floated in the current. So I let it settle then put a 1" layer of regular aragonite reef sand on top to hold it down. It worked perfectly. My macros are growing better than ever. My pods, worms, stomatella, white flat worms etc. All florishing. My nitrates and phosphates are unreadable on api tests. Reef is doing awesome. So, here's the thing. I look every night with a flashlight. All the life seems to be in that top layer of sand. The oolitic looks undisturbed. 5" of oolitic. Just sittin there. And I wonder, should I have done all regular sand? Or are there things going on in that oolitic that I am unaware of? Opinions?

 

[Rpujol85]

I'm not a scientist but.....my understanding is that the DSB creates zones for specific types of bacteria (anaerobic) to develop, which in turn process nitrites(?). So you will not necessarily see anything happening.

However from experience I'm guessing this tank has not been set up all that long. I think eventually you will start seeing gas bubbles develop in the DSB as well as what looks like what I can only describe as patches of mold (which is what I believe to be the pockets of aforementioned bacteria).

Any clarification is welcomed.

 

[Wiz]

Tank has been set up for about 4 months I beleive. I'm horrible with time. Lol I have harvested alge 4 times. The top layer of sand has the colors and bubles. But that's it. The oolitic has nothing. Maybe it just takes time to go that deep. But the phosphates are all but gone. And I was able to stop vodka dosing on month 2 without any nitrates returning. So its working. :-D

 

[Wiz]

Update.
The oolitic sand now has life, trails through it, gas bubbles coming up. Took a bit. But it is working as its supposed to. Removed my phos reactor a few months ago. Dsb fuge is keeping my overstalked system clean and healthy. :-D

 

[Randy Holmes-Farley Verified Community Expert]

I didn't think that my deep sand beds using oolitic aragonite were doing much useful, so after a few years I got rid of them.

 

[Wiz]

Do you have to run gfo or carbon dose to keep nitrate and phos in check?

I didn't think that my deep sand beds using oolitic aragonite were doing much useful, so after a few years I got rid of them.

 

[Randy Holmes-Farley Verified Community Expert]

Do you have to run gfo or carbon dose to keep nitrate and phos in check?

I presently use skimming, GFO, growing macroalgae, large rock filled refugia, and organic carbon dosing (vinegar).

 

[brandon429]

How do we know it's not the algae doing the binding and not the sand so far

 

[Wiz]

Obviously I can't be sure it is the dsb fuge that accommodates it. But all I run now is a sca-301 65g skimmer and a small carbon bag. The system is an overstocked 40b with all types of coral, cuc, and 9 fish. The 30g fuge and a 20 long sump. Subtracting mass for sand and rock in the neighborhood of 60 gal of water. Has been this way for a couple months now (since I removed the reactor). And I feed quite liberally. Nitrate and phos are undetectable on my api test kits. I have to attribute this to the fuge.

 

[Wiz]

I ran the macro in a smaller sump with little sand before switching. And nitrates were as bout 10 or less. Phos was high. But your right it sure could be the macro. the thing for me is a "natural enviornment". So sand is a must. And I love the microfauna as well. I find watching the worms and bugs traveling through and on the sandbed very interresting. So as long as its not hurting the tank I like the sandbed just for viewing purpose.

How do we know it's not the algae doing the binding and not the sand so far

 

[Wiz]

Also there is a lot of gas working through the sand. So its doing something ;-)

 

[Naiad]

Just be very careful nothing disturbs the deep sand and if it does that you shut the system down asap for water changes.

 

[Windy]

If you read Schimek's article, then you know he says to use micro fauna to keep water moving through it. How have you seeded you DSB?

 

[Windy]

r

Just be very careful nothing disturbs the deep sand and if it does that you shut the system down asap for water changes.

Where do you get your information. I have run DSB's since the '90s. You have to have sand stirrers. In fact Shimek talks about as many as 40,000 micro fauna per cubic foot of sand. This turns the sand over and helps get water movement. I have disturbed DSBs many times, moved them and re-set them up. What is so dangerous about them?
I am not advocating DSB's but if you don't know what you are talking about, your advice may be harmful.

 

[Wiz]

Just be very careful nothing disturbs the deep sand and if it does that you shut the system down asap for water changes.

The only things In the fuge are snails and macros. There are cerith and nassarius snails but they don't go to deep and are not an issue.
Also in my research I've read that the dangerous gas only builds when there is not a good supply of microfauna to allow for the slow release of it through their travel cavities. And this is noticeable through the glass as black or dark areas in the depth of the sand. As long as the gas is able to escape slowly a build up is theoretically not an issue. I ne youtube vid showed a two week experiment where the owner purposely disturbed (stirred) a small area of his dsb. Over the next coupe days the lack of fauna trails in the disturbed area caused a black area. But over the next two weeks the fauna from the rest of the bed repo ppl ulated the area and he showed a time lapse of the black area shrinking as the trails reappeared. Very interresting vid

 

[Rpujol85]

I think the danger is in releasing all of the trapped gas at the same time? But I have "disturbed" mine more than a time or two without any noticeable consequences.

 

[Wiz]

My fuge is built based on his article. From the grain size to depth. Exactly. Such a great article. I used a bag of fresh live sand, an inch layer on top of my old fuge sand which had a slightly bigger grain size and was full of critters, some bristle worms from a forum member and two orders of pods from different vendors. As well as multiple macros from various venders which I'm sure brought stuff in. So far I've recorded over 9 types of worms and 10+ types of "bugs" as well as mini chitons, snails, limpets, micro britles etc... defanitly full of life. Although I'm always looking for more ways to seed it. So if you know any, don't be shy

If you read Schimek's article, then you know he says to use micro fauna to keep water moving through it. How have you seeded you DSB?

 

[Naiad]

Sorry I should have been more clear. Yes you want the microguys to stir and you can stir small sections if the bed I just ment if a powerhead or pump somehow disturbs large portions. If 100 % of your bed is working properly you will be fine but we can only observe the small outside section and I personally would not want to take the chance with my livestock that a "deadzone" didn't exist somewhere.

 

[WetWhistle]

I find nowadays DSB are not as big an impact on reef tank for Nutrient cycling as they once were to this hobby. Unless you dedicate a tank that has lots of it. They do work and are very productive for microfauna and helping to add to the food web. But as far as nutrient processing we have so many other options now that it is not as big an impact that it once was years ago. I still keep mine but not as deep as I once did. I found that after I changed my refugium and it was up and running that after a year of being set up and undisturbed, with all the Macro algae I didn't need as deep a sand bed. I myself don't like bare bottom in my tank so at the very least I would keep it for that.

 

[Randy Holmes-Farley Verified Community Expert]

I think the danger is in releasing all of the trapped gas at the same time? But I have "disturbed" mine more than a time or two without any noticeable consequences.

Any trapped gas you can see is not toxic. It is either nitrogen (most likely) or just air.

Hydrogen sulfide that may be produced if a lot of organic matter gets buried is not going to be present in the gas phase, but will show as black precipitated metal sulfides.