deep sand bed cover image

Are deep sand beds just a thing of the past?

When I started in the hobby, deep sand beds were trending towards the end of being in vogue…that is, I guess if one could ever consider deep sand beds to ever have been in vogue. As a side note here, I don’t think I’ve ever used the phrase in vogue before, but now I’ve done it three times in the span of 60 words, but I digress.

At the moment, I’m feeling like one of those old guys clinging on to the way things used to be, wondering, are deep sand beds just a thing of the past?

I wonder if I’m the only one left in the hobby with a tank that has a deep sand bed.

Advantages of deep sand beds

From my perspective, a deep sand bed carries a few advantages over a bare bottom tank.

Water purification advantages

From a water chemistry and purification perspective, what I love, love, love about my deep sand bed is that there is a ton of surface area for both aerobic and anaerobic bacteria to live and grow. Those bacteria turn ammonia into nitrite and nitrite into nitrate, essentially becoming a fantastic live sand.

“But Al,” you’re about to say, “the bacteria in my tank do the same thing, and I don’t have a deep sand bed.”

Very true, but allow me to finish. Deep within my sand bed are anaerobic bacteria—bacteria that grow only in the absence of oxygen. Those bacteria actually remove nitrate from the water.

My deep sand bed acts as another living water purification system and helps clean my water for me.

Aesthetic/Interest advantages of deep sand beds

In addition to the functional benefits to water chemistry just described, here is another reason I love my deep sand bed:

deep sand bed 2

Critters. Yup. Critters. All sorts of critters. Green stuff, brown stuff, little worms, little pods. One of my favorite things to do is take a look at my sand bed at night to see what’s moving around down there. I don’t know exactly what all that marine life does…but I have to think they’re also turning one sort of waste product in my tank into their food and processing it for me.

engineer goby

Engineer gobies need a deep sand bed to burrow in

Last, but not least, my deep sand bed is home to some other pretty fun animals—my burrowing fishes. At different points in time, I’ve kept jawfish and engineer gobies, which are fascinating to watch. The gobies seem to never stop building, and the jawfishes are just amusing to watch, as they bob up and down, afraid of their own shadows.

yellow headed jawfish

The downsides to having a deep sand bed

At one point, I did lose some coral tissue (not the whole animal), because a goby pair insisted on burying it, day after day until I moved it far enough up.

The sand does get dirty, from time to time. If you’re a complete neat-freak that has a low tolerance for any brown stuff in the tank, this might not be the look for you.

Last, but not least, is something I haven’t seen written about in a long time, probably because not a lot is written about deep sand beds these days—but the older literature talks about a risk of old tank syndrome or the leaching of toxic chemicals from that anaerobic part of the bed that I’m oh, so proud of.

I’m not sure if it’s the diggers that have kept me in the safe zone, just dumb luck, or if a tank catastrophe is about to happen at any moment (no doubt accelerated here by ‘jinxing’ it and writing about it right now), but the fact remains that my current tank has been running for somewhere around 8-9 years, at this point, with a deep sand bed, and it’s as alive and vibrant as ever.

deep sand bed cover image

I guess I’m a bit old school. I’ve certainly always been stubborn, but I love my deep sand bed and I’m convinced it provides a level of biological filtration and stability that allows me to be a little more laid back about all the maintenance.

Am I the only one out there? Let me know what type of sand bed you have with a comment below.


  1. i am starting up my tank again, In the past i always had a deep sand bed, ( my tank is a 180 with a 110 gal sump/ref.) The tank almost took care of it self, i only had leathers, but I am looking for the easy/safe substrate. bare bottom is ugly(sorry) so its 1 inch or 4 inch. what do you sugest?

    1. Author

      Hi Starr, thanks for the question and welcome back! For the dep sand bed to work best, it needs to be deep. Try to get 6 inches if you can. And I totally agree with you, it does make things easier!


  2. My tank is 75 gallons in the display and a 26 gallon sump. My sand bed is 4 to 7 inches it was 5 all the way across but a combination of flow , clean up crew and fish have shifted it deeper in areas and less in others. my tank has about six years behind it and I don’t clean my sand. I do however have two types of burrowing snails fighting conchs and worms that do that for me. I have not done a water change in years I do however dose using kalcwasser and magnesium and when the salt gets a little low I use reef crystals to replace other trace elements. I have 16 fish and 23 corals in my mixed reef. I love it and am very happy with it.

    1. Author

      Timothy, thanks so much for sharing your experience here! That’s a long time without the old “weekly” water change. It is amazing what the deep sand beds can do in terms of creating a balanced system. Sounds like a gorgeous and thriving tank. Kudos!

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