MMcDonald 55 gal Build

From my understanding, and in my opinion, deep sand beds are finicky things. They are not fully understood by most people who use them, even people who are very experienced with them have had problems (like tank crashes) that may have been potentially attributed to them. I sound uncertain because I think (and that's how it's been portrayed to me) that's how difficult it may be to identify when you're actually having a problem with a deep sand bed. Most of us are hobbyists, not marine scientists and don't have the ability to do thorough water tests and examine water/sand/etc samples under a microscope or under some sort of fancy lab equipment to help determine what actually went wrong.

I think you can probably get most of the benefits of a deep sand bed without most of the risk through other methods. Most people use deep sand beds primarily for denitrification/nitrate export which can be handled through a variety of other means such as refugiums, algae turf scrubbers, remote deep sand beds (not in the display tank but still plumbed into the system, like a refugium), carbon dosing (vodka/vinegar/sugar etc), denitrifiers (sulfer denitrification reactor types), or "solid vodka" reactors (which are relatively new on the market), and probably other methods which I'm not thinking of at the moment.

Either way there are other potential solutions available that don't carry the same risks (not to say they are risk free/effortless themselves). I think it's probably worth some investigation personally since it's probably the main export process that most people struggle with (which is nitrate reduction, because phosphate reduction can be simpler via GFO and other chemical means as well as turf scrubbers/refugiums and to some extent carbon dosing, etc).

If you are planning for your display tank to be only setup for a few years then I think a deep sandbed is potentially a great source of denitrification and a great habitat for lots of interesting animals, jawfish, lots of cool worms, great for certain wrasses etc. But once you get to have an older deep sandbed you run into issues and restrictions with doing certain things with your tank.
For example, if at some point you want/need to remove some of your rock in the tank and it's buried in the sand, do you risk removing the rock for fear of disturbing the sand?
Lots of people find they need to move or upgrade their tank within a 5 year (or so) period of setting up their tank, this could pose some problems, as well, as you don't want to disturb the sandbed when moving unless you're really planning on getting everything out of the tank reasonably quick, because it could release some nasty stuff into the water.

Anyways, just weighing in with my thoughts on deep sand beds. I don't want to deal with them in my display tank but they aren't necessarily bad things, just be sure you understand the potential pitfalls associated with them before undertaking one in your tank IMO.

 

Thanks Screwtape. I had read essentially the pitfalls you wrote about and thus the need for sand sifters to not allow those pockets to develop. The DT sand bed is just over 3" so it barely qualifies as DSB. I think I'll give it go and see what comes. One thing that I do truly enjoy about this hobby is that it is not fully known or absolute. Makes it more fun. Everything has its pro's and con's. Risks and mitigations. I like the challenge.

M

 

Just to clarify if you have sand sifters that actually get deep enough to disturb the anoxic zones (I'm not familiar with any) then you will not get as much benefit from the sand bed. You want those low oxygen zones to develop, that's where the denitrification happens. That's why you don't really want to disturb the deep parts of the sandbed.
The top layer is fine to have sifters like nassarius snails, that will always be relatively high in oxygen. But having a deep sand bed doesn't necessarily require sand sifters of any sort.
Not sure if you've seen this before, it might help though.
Ron Shimek's Website...Deep Sand Beds

 

Hmmmm.... let me read it again. One thing I have learned quickly in reefing is that there are many opinions. There was someone else on the forums that was telling me about the snails to add. Let me go back and read some more.

Better to resolve this early than too late.... It is easy enough to take some sand out now if needed.

Off to read some more.

Mark

 

I re-read Shimek's article. He specifically references putting a DSB in his 45 gal. tank. Thus, I was replicating what he was discussing. The sifting is an interesting distinction though. I know that I have read specifically to add some snails for that purpose, and he specifically says not to. I will research that more.

M

 

Yeah I'm sure Shimek is very familiar with how to handle a DSB and is fully aware of how to care for them. Not everyone is.

There definitely are lots of opinions, careful who you believe and why you believe them, obviously myself included. Kudos on the research!

One other direction I might point you in is Eric Borneman's thoughts on DSB's, he is another big believer in them so he would be a good person to read up on as well. He has a forum on Marine Depot's forums and has a bunch of info out there, pretty good resource I think.

 

The other thing hat hit me in the article was Shimek's removal of the GARF Grunge sighting it as causing a problem for worm access in the top layer. Coincidentally, as I was reading the article, my 25lbs of grunge FINALLY arrived after having ordered it two weeks ago. The bags inside the box had ruptured, thus the box was soaked through. The post office had wrapped it in plastic. When I removed the grunge, to look at it. I was totally unimpressed. It is essentially cement gravel and dirt with some sea shells mixed in. I was looking for bits of coraline colors or creatures that are advertised. I could see no evidence of either. Granted, the bag had leaked and any creatures were probably dead.

Leroy at GARF promised he would send a replacement order. SO, I will look at it when it arrives, but I am not so sure that I am putting that in my tank. Given Shimek's article sighting it causing problems and the look of it, it probably is not going in.

More reading to go do.

Mark

 

I have read several articles at RC archives too about DSBs and considered them beneficial. I have 3" or so in my DT, but I won't go over that. Much of the bed had rock not sitting on it, and I have good flow. Lots of worms and about 10 Nassarius snails. My bed bubbles nitrogen all day long and always has. Mt fuge has 5" DSB. 2 inches of clay and 3 of oolitic. However, nearly 8 months later it does not bubble. I have worms and bristles in ther. I put 4 nassarius in there to day to till the sand and we shall see how that does.