The Pros and Cons of a Bare-Bottomed Marine Tank

bare-bottom-tank1If you’re in the process of planning and setting up a new saltwater aquarium, you’ll need to give some thought to the type of substrate you’d like to use. It may seem counterintuitive, but one of your options in this area is to dispense with any sort of substrate altogether and go bare-bottomed (BB). To help you decide whether the BB approach might be right for you, here are some of the pros and cons to consider:


  • Very easy to vacuum up uneaten food, fish waste, and other detritus that has settled to the bottom without siphoning up sand in the process.
  • Allows you to aim the effluents of powerheads and other sources of water movement in any direction desired to maximize water flow throughout the system and behind rockwork without creating an underwater “sand storm.”
  • Detritus more readily remains suspended in the water column so it can be filtered/skimmed out efficiently.
  • Cost savings from going sans substrate can be significant depending on the size of your system.


  • Arguably less natural looking, though this is a matter of taste. (Plus, coralline algae and, potentially, various encrusting invertebrates will eventually conceal the bottom, giving the system a more natural look.)
  • Can’t keep burrowing fishes as easily. Some BB aficionados get around this by placing a substrate-filled container somewhere in the system.
  • Having no sand-dwelling microfauna can mean lower biodiversity.
  • Greater risk of cracking the bottom pane in the event of a rockslide (can be circumvented by properly securing/stabilizing the rockwork ahead of time).

What have I missed?
Of course, these are just some of the BB pros and cons off the top of my head. If any of you salties out there have more to contribute, I hope you’ll share them in the comment section below.

Photo credit: Stéphane Duquesne


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About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. I had a bare bottom tank for my seahorses which really helped clean up the uneaten food. Just thought it didn’t look very interesting

  2. Paul Baldassano says

    Bare bottom is just un natural as it looks like a dealer’s tank. The main purpose of substrate is to have more area for bacteria and micro fauna. Bacteria and micro fauna run our tanks and we are just there to give the bacteria something to make fun of. A truly natural tank has either sand or gravel on the bottom. Fish find food and shelter there.
    Bare bottom tanks just make me feel sad.

  3. The big question for me would be, is live rock alone enough for adequate denitrification in a bare-bottom aquarium? To go the bare bottom route, I would recommend employing a plenum. That way, you can have substrate to support microbial processes, while enjoying a bare-bottomed main tank.

  4. Harold Weiner Aquatech says

    A contentious subject for aquarium owners, I suppose it ultimately depends on personal preference. Great food for thought!

  5. Matt Bowers (Muttley000) says

    Don’t shortchange how much a marine substrate can help with buffering capacity. Those with long running systems have likely noticed that the sandbed shrinks over the years as the sand gets “used up.” Not that a bare bottom tank won’t work, just another con to consider in the decision making in my opinion!

  6. There are a lot of excellent insights here. Thanks to all who shared a comment! I have to say I’ve always been a fan of using a substrate if for no other reason than I just prefer the look of it.

  7. Great article. I really like substrate because I’m trying to mimic a reef’s natural environment and it just looks esthetically pleasing… to ME. No way saying one is better than the other. Plus it’s fun watching the wrasse do its daily ritual along with watching my other sand dwellers.

  8. A bate bottom tank would greatly eliminate phosphate build up from old food and detritus that accumulate there. Of course there is the matter of light reflection of the bare bottom. You could use zooanthid and other invertebrates to make the tank look natural or of course use saltwater plants to provide the natural look like halimeda or maidens hair.

    • Dee,

      This may be anecdotal but my current experience using an ozone generator seems to have resolved the detritus buildup in the substrate which may have been also causing cyanobacteria patches on my sand even though I measured 0 ppm for both Nitrates and Phosphates.

      • I’m more of a naturalist keeping the equipment down to basics. Ozone isn’t something that i would recommend a new reefer play around with. If you’ve ever taken down a tank with a deep sand bed you’ll see that the equipment running is usually offsetting the phosphates generated in the tank. You find a heavy load of dirt in there as well. Now I Happen to enjoy having a sand bed but don’t keep a deep one.

  9. My bare bottom tanks seem less stable.
    I have experienced tank crashes in my bare bottom tanks, whereas my tanks with aragonite sand substrate do great for years at a time! I think the live sand helps to process the waste and to breed food for the fish and corals, as well as buffering the water and releasing calcium.

  10. I actually prefer barebottom. I even prefer the look of it because I have coral encrusted on the bottom so instead of looking like I am at the bottom of the reef where the sand is, it looks more like the top of the reef when you are snorkeling. For me, that’s like a nostalgia thing. Also, it’s a cinch to clean. I highly recommend adding calcium though, because some natural calcium will come from the crushed shells in the sand. I try to dose naturally and test often so I grind shell or cuttlefish bone into a powder (I noticed shell works better, but cuttlebone will work in a pinch and it’s cheap). I just love the look though. This particular tank is going on three years old with no crashes and no significant losses. I have no complaints.

  11. Deefrombrooklyn says

    Having no sand means there is much less wear on powerheae impellers and other equipment. You also don’t worry about nutrient absorbing in the substrate.

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