[Das]

G'Day ,

Many forums at the moment are disputing DSB's or bare bottom and as i am currently half way through building my 500 plus gallon plywood tank i have started to wonder myself if a DSB is the way to go.I have played with the idea of a bare bottom tank with a remote sand bed as my sump is going to be 300 gallons and i will also have a Ref at 150 gallons.I currently have had 110G FOWL tank up and running for 4 Years with no dramas at all and going into a reef setup is a big step but down here in Aus there has been great support on RTAW and i have planned my tank out very hard but one night searching through RC i came upon a subject on DSB's that was disturbing as once my reef is up and running i expect( with good maintanance ) it will be up and running longer than 3-7 years without crashing.I am not trying to cause a lengthy thread on DSB's but alternatives to a DSB.

Your suggestions would be greatly apprieciated.

Thanks DAS.

[Ninong]

G'Day, DAS, and welcome to Reefland!

In your particular situation you could go either with or without a deep sand bed in the main tank and still have most of the benefits of a deep sand bed since you are planning a large refugium.

The most obvious benefit of a deep sand bed is that it is an excellent resource for processing waste and producing food for your main tank's fish and corals. It is probably more effective at denitrification than live rock and has the additional benefit of providing a constant source of nutrition in the form of polychaete larvae, etc., for the rest of the tank. Both of those benefits would be available to you in your refugium, just not in the same volume.

Most folks who favor deep sand beds are attempting to achieve as complete an ecosystem as possible in their little piece of the ocean. The deep sand bed in the aquarium provides additional pathways for energy and waste management. You could achieve these benefits without any sandbed at all in the main tank if you had a really large refugium with a gravity flow feed into the main tank. The refugium would be a source of zooplankton as well as a denitrification resource for the main tank. This would permit you to go with no sand bed at all in the main tank if that is what you wanted to do. The most obvious 'benefit' of no sand bed in the main tank is that you can turn up the water flow without having to worry about turbulence stirring up the sand bed. You would probably want more skimming capacity in the system if you chose to go without a DSB in the main tank.

Most of the recent discussions on Reef Central about deep sand beds center around the question of whether or not heavy metals accumulate over time and, if so, is that really a problem or not. If you accept the possibility that it might be a problem, it would be a problem for all of the live rock in the aquarium, too, not just the sand bed. There are those who are convinced that metals accumulate to toxic levels in reef tanks due to excess metals in the salt mixes and from feeding over long periods of time. Others are equally convinced that these heavy metals are not a problem because they are probably bound and not available anyway. You have biology Ph.D.'s on one side of the argument and chemistry Ph.D.'s on the other.

I can't say that I personally know anyone whose tank has crashed as a direct result of problems with a deep sand bed but that is not to say that there aren't any out there. I do know of several people who have been maintaining reeftanks with sand beds deeper than 4" for at least 3 or 4 years, or more, without any problems whatsoever and I also know some people who are maintaining reeftanks with either no sand bed at all or a very shallow one with no problems whatsoever.

My personal opinion is that a reasonably deep sand bed (greater than 5") is just a natural part of the total package and something that adds diversity to the total ecosystem.




P.S. -- Here is a link to nine articles about deep sand beds by Dr. Ron Shimek (just scroll down until you reach the topic, Sand Beds) -- http://www.rshimek.com/reef/OnlineArticles.htm

P.P.S. -- Here is a link to a current thread on Reef Central in which several members who have had deep sand beds in their reeftanks for two to four years are reporting problems with hair algae that they suspect is the result of phosphate leaching up from the deep sand bed: http://reefcentral.com/forums/showth...hreadid=210605

Phosphate is something that is not processed in a DSB according to the articles written by Dr. Shimek and therefore it should be exported via macroalgae harvesting or some other means. Dr. Rob Toonen has extensive experience running reeftanks with deep sand beds and he has written on this topic, too, but I don't believe he was published, at least not in the popular media, but I know that his tank at UC Davis was running with a DSB for several years. There are a few other hobbyists that I read about on the boards over the past couple of years who reported running DSB's for several years (5 or more) without problems but it looks like some of the more recent converts to the DSB 'theology' are recanting.

[saltwaterdave]

Everything you read is not true!
Saying that, I saw a thread recently where a person has a DSB for a little over 9 years....very encouraging!
That being said and with all the debates going on,just to play it safe,if I could I would use 2 different remote fuges or sumps with a DSB.They would be plumbed seperately,that way I could take one offline,change out that DSB while the other continued on.Then say after a few years change out the other DSB. Just seems like a logical thing to do if you were able.I am sure someone could and can find flaws in this reasoning.....but the way things change so fast it seems in this hobby,it at least has a chance.
David

[organicreefer]

DSB'S dont work long term.period.even shimek has conceded that fact..while yu may ba able to point to a tank thats been using a dsb for 9 years-id like you to show me another -meanwhile they are numerous tanks i can point out that old or older with shallow beds or bare bottom... .i can most definitely say that with my exp with dsb's over the last five years-ive learned my lesson and have been removing the sand frm my tank.
remote dsbs are even worse..they last even less time.the higher flow in the main tank will keep more of the detritus in suspension and it will settle out in the lower flow refugium -where it will quickly overwelm the critters there -they will fall behind and youre sand bed will clog up.been there done than.
i would advise you to listen to the nay sayers logic..the current thread going on over at rc is a good one -particularly the last few pages .jc delbeek even just chimed in also check out thereeftank for some good info on the limitations of dsbs.
dsbs do work wonders for a period of time -but they will eventually get full and then the problem algea starts-been there done that.they are excellent at processing nitrogen..but tell me what happens to the phosphates??they build up and leach out -been there done that..
dsb's have only become popularized by american online message board hype imo-and the rest of the world has largely ignored them ..youll be hard pressed to find many european tanks running them -and for very good reason imo.
bottom line is -dsb's incorporate nutrients into a closed system ..not a good idea at all..you must export nutrients from a closed system or they will build up over time in one form or another -and eventually cause problems.
ill never have another dsb again-they simply do not work long term for the kind of tanks most of us want to keep.

[tendar]

I am in the process of setting up my tank to replace a old one that currently has a deepsandbed for 2 years no problems.
The new 60 tank will only have a 1/2" sand bed in it for mostly looks and clams.
I will run a Aqua-C ev180 skimmer which is over sized for a 60 gall tank but will be very effective at keeping the tank clean even on a upgrade some day to a larger tank.
I will also latter on be adding a remote refugium with 6" DSB with will hold turrrle grass but this will also have pretty good flow so detris does not settle in it eitherand can easly change out sand if needed should a problem arise.
I believe my self that I will get the best of both worlds but will see in a few years.
I think some people are making was to much stink of dsp. If properly maintained and has good glow over the sand bed to keep detris from settling on it and and building up they can last a lot longer than a few years along with some siphoning off of the top layer and adding new sand every year or so or stiring the top 1/2"-1" layer of the DSB now and then to get and build up of detris up in the water colum to be removed by a good skimmer or even some filterfloss run at stiring time then removed plus it helps feed your corals much like blowing off your rock with a turkey baster now and then. I just like the sound of a remote gravity feed refugium with good flow and DSB for easier maintence and low detris build up if any.
My 2cents