29 Gallon, DSB or NOT?

[SaltyinNJ]

Hi, I am setting up a 29 gallon reef with 3x55wt PCs, HOB skimmer (no sump) and I am not sure whether or not to go with a deep sand bed (4").
From what I have been reading, on a tank this size it might not really be effective. But, it is not really clear. The other negative is that in a tank this size it takes up a lot of space. If i don't do the DSB I was thinking of just going with 1 to 2 inches in depth. Bye the way, I will be using SouthDown sand.

I would appreciate opinions from more experienced people. I have been maintaining a successful 7 gal minibow for almost a year.
Thank you in advance.

 

[wombat1]

DSBs work regardless of tank size, as long as they're properly constructed. You would only lose 2 inches to make a 4" DSB. I plan on having a DSB in my 6 gallon tank.

 

[olgakurt]

I've had a 20 g reef w/a dsb since 1990. IMO, in smaller tanks (like mine) you may be better off working on getting a lot of flow than in trying to get bed depth. Denitrifying conditions can develop in much less than 4" of sand, but in tanks with a small foot print, it is hard to maintain a diverse population of fauna that will work the sand. I'd shoot for atleast 30x turnover flow.
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[Modo]

I first set my 29g (no sump as well) up with a course arganite sand. Nitrates were always really high and had to stay on top of it with H2O changes. I did a switch and added a 4-4.5" Southdown DSB. It took some time but my nitrates stay lower even up to the time of an H2O change. I would imagine if I had gone deeper or had a larger tank or sump that I could achieve 0 nitrates, but I don't have that luxury and my tenants and I are happy with it.

I doubt I have sand fauna like someone with a 300g system, but I definately have LOTS of life. This includes worms of different sorts, lots of different pods and tons of those tiny brittle stars. All of which came from LS I've traded locally or off the LR.

IMO, I would go with at least a 4" DSB. Think of it as not losing space but gaining a beneficial "filter". Plus, if you plan on having corals this will lift up your rock closer to the lights.

 

[SaltyinNJ]

Thanks for the responses. One thing that came to mind. If I do go with the DSB, if I place my rock in the tank first (which I was told would make it more stable) then add 4inches of sand. Won't that cover up too much of my LR and maybe have a negative effect on it's bio filtration effects?

Or do I lay down an inch or two of sand first, then add the rock, then fill up with the rest of the sand?

 

[wittyfellow]

I'm not sure if you would actually want to put your live rock at the bottom then start the sand bed.

I have a 6" sand bed in my 55gal and I started with PVC pipes, cut at 6.3". several are placed throughout the tank in the sand bed to support the live rock structures. I have 12 pieces of PVC piping all together supporting 65 lbs of live rock. This allows your rock to NOT touch the sand and for your sand critters to get under the rock and stir the sand throughout.

Also, if you wanted to, you could just use base rock at the bottom before putting the sand in, but that's obviously more expensive.

Let us know how things turn out, pic et al... I'd be interested.

--a

 

[olgakurt]

You will support different fauna with different niches. In a small tank, again, I think it is difficult to get long term self-sustaining populations going. So it may be kind of moot, but some fauna may be able to hang on longer than others. I would opt for the rock concentrated in one end/corner of the tank on top of the sand with a single piece half buried in the sand at the opposite end of the tank.
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[Modo]

I opt for the rock in first and then sand. Just use base rock for the bottom and LR for the "seen" portion. IME, this makes for a lot more stable rockscape. If you just set it on top of the sand current, fish, crabs, shrimps, stars, etc.. may tunnel and cause a landslide possibly breaking glass or crushing animals.

As for Olgakurt's response on supporting fauna, from experience with my 3+ year old 29g tank I have a large variety of detrivores, sponges, etc. that inhabit different parts of my rock work and sand. Just because a tank isn't 6ft long doesn't mean you won't end up supporting very interesting inhabitants in all the different niches in your tank over time. Things will balance. I notice population fluxes with pods, stars and worms alike. Sometimes you click on the lights at night and it looks like you stirred up an ant bed and sometimes it seems dessilate. But, I do feed heavily and don't have many predators like wrasses or shrimp.

 

[Will C1]

modo has a good idea just put crappy base rock or even tufa rock (just be shure to wash it first) down first it will make it more stable my 90 reef has tufa in the sand and i'm glad i did it my engineer goby has tunnels under all my rock now. i would hate to have seen what would have happened if i haddent.

 

[MiltonP]

In my 29 I put a 7"x22" sheet of eggcrate supported by 8 columns of 1/2" pvc that are 3.5" tall with crosses cut in the tops to hold the eggcrate. The platform which will be hidden in a 4" sandbed currently hold 28 lbs of rock. There is space around the platform for tunneling creatures.

I am currently 10 days into in-tank curing and only have 15lbs of 'dead' sea floor sand in the tank so far. I have not decided how much live sand to add yet. It looks like a maximum of 23 gallons will fill it up.

 

[royy]

With Southdown you can get a good denitrifing effect with 2-3". I have 3" bed of Southdown in my 90 and have 0 nitrate and nitrite readings. I did top off the Southdown with a larger grain sand. I used the prebagged live sand you can get at most LFS. This has nitrifing bacteria in it alreaady, just no pods or anything.

BTW, where in NJ do you live? I am in Bayville which is just south of Toms RIver. Exit 80 on the GSPW. Maybe we can trade some frags. I just broke a nice piece off of my monti while cleaning.

Roy

 

[SaltyinNJ]

I like the idea of using base rock below the liverock. It sounds easier than some of the other suggestions and it sounds like it would be stable.
I think I will go for that one.

Royy, I live in south Jersey near Cherry Hill, so we are pretty far away from each other.

Thank you everyone.

 

[Rook]

I have to disagree.

I am preparing to switch from cc to dsb in my 29 reef. I have researched this a great deal, including reading articles from and asking Dr. Ron Shimek. In a 29 gallon tank with the small foot print, which is effectively reduced due to the ineffectiveness of the 2" area around the glass, you may not be able to sustain fauna, which is the key to the system. Of course you can always add a recharge kit once a year which is recommended anyways.

With the foot print being as small as it already is, I would put the rocks on top of the sand. Otherwise you are making your dsb even smaller, thus even less effective. Having the rock on top of the sand will not effect the effectiveness of the dsb. The fauna can easily move around under the rock.

As for stability, I had a jaw fish burrow under my live rock like crazy and it did not cause any problems. Just make sure to stack it properly and support it on the back glass.

That is my opininon anyways.

 

[MiltonP]

I painted a 2.5" black band around the bottom perimeter to keep 3" of sand in the dark. I also painted the bottom as this tank is on an open stand. I used Perm Enamel which creates a tuff-coat look.