Bare bottom/little sand/normal depth sand

[Moosetache]

Just wondering about something. I am setting up a new tank and I would like to keep a lot of sps in there. I was told that it is much easier to keep sps in a bare bottom tank or a tank with little sand. Makes it easier to get the nitrates/other contaminates out apparently.

Can you all give some additional info on this thought.

Thanks!

[brandon429]

yes that is the currently held view for this decade I would agree.

[AdamDeMamp]

You're going to get responses from both sides. I have had BB tanks on my last 2 tanks. I just like it better.

[bertoni]

I think it's a matter of personal preference, for the most part. A bare-bottom tank can be easier to manage if the feeding schedule is heavy, though. It's more manual maintenance, though, to take advantage of that.

[Moosetache]

What do you mean by more manual maintenance?

I guess I am also just one of those people that think that sand should be a part of the aquarium look. Not sure how I would feel about no sand....

[keithhays]

I think you will find awesome sps in both types. BB vs Normal sand bed is one of preference of looks and of maintenance. You will need to and can have greater flow in a tank that is BB because the flow alone is capable of getting rid of the vast majority uneaten food and detritus, but you will have to collect in socks and protein skimmers. This is why the water will ultimately be cleaner, if not it will be worse than with the sand bed. The DSB is a different story, the DSB is used for denitrification as well. It cannot be regularly cleaned too deeply or the denitrification aspects are lost. They have a tendency to crash any number of reasons, but the one that happens frequently is a powerhead falls into the tank and digs up the DSB. The DSB produces sulfides as byproduct of the denitrication process, but are normally not release in mass to the aquarium. When the proverbial powerhead digs it up, massive amounts of sulfides are released all at once. The other type of crash is not really well understood, but without disturbance they have a tendency to only function for 3 to 5 years. This is why you will see systems with remote DSB's that can be pulled out of the system very quickly and replaced with out disturbing the sand bed prior to that time.

[bertoni]

We can only speculate as to which approach might give cleaner water. We don't have any cost-effective tools for measuring low nutrient levels. I think a sand bed is prone to causing problems if the tank is overfed, though.

[biecacka]

More manual labor as siphoning the debris off the bottom of the tank on a regular basis etc
Corey

[Signal151]

I've been in this hobby for 18 years now and the more I learn and the more I speak with aquarists who have managed to maintain SPS reefs for 10+ years, the more I'm leaning toward the sandbed being the culprit behind "old tank syndrome". Meaning, without extreme measures, the sandbed's slow accumulation of phosphates over time will eventually lead to a system crash. By extreme measures I mean some sort of complete sandbed replacement every other year or so and/or routine sandbed vacuuming.

[bobkill]

I have a Small sand bed - 1-1.5inch I don't really like bare bottom look - and keep in mind lots of flow can more even a very thin layer of sand around - i agree will the people of above -

[AcroporAddict]

If you have enough flow in the bare bottom tank, it will be relatively spotless. I have a 465 gallon BB sps tank and I have about 43,000 gph peak flow in there from the return pump, four MP60s and two MP40s, and I have only spot siphoned debris out of there twice in 6 months, which was just little bits of LR that had come off the rock structure. I use 100 micron mesh filter socks and an Alpha Vertex 300 skimmer, along with a GFO and carbon reactor, a calcium reactor, and a sulfur denitrator.

Hate to say it, but at times the tank looks too clean on the bottom, but everything is growing. Ca, Mag, KH are all good and steady thanks to a Masterflex peristaltic pump feeding the GEO 818 Ca reactor. The reactor keeps the Ca, Mag and KH at normal levels and I haven't had to dose manually since I set this tank up. Just about to hook up a second Masterflex pump to the sulfur denitrator as a feed pump. Once you have that kind of flow rate accuracy in your reactors, you just get spoiled.

I keep up with rinsing out the filter socks and emptying the skimmer cup, but there is not any other physical removal of detritus other than the occasional siphoning out of settled mulm in the 155 gallon sump. My water changes are semi-automated, so I just have to turn valves to fill and empty the sump. I do good sized water changes on this system as well, maybe one thirty gallon water change every 6-7 days. Total system volume is approximately 450 net gallons.

My tank has a hybrid PVC/glass bottom with the top layer a 1/2" thick dark gray PVC sheet, and the bottom a 1/2" glass sheet. It is covered with pink/purple/red coralline algae. I think dark PVC lends itself to a more aesthetically appealing BB look, and high flow just makes it easier to keep the tank bottom clean. The in tank flow does all the cleaning for me. I just have to keep the front and side glass clean.

[tmz]

Not much denitrification goes on in deep sand,unless you keep sand critters replensihed to channel nutrien nts down into it.Defussion isa weak force and doesn't move very much down into the bed. Most denitrification occurs in the first inch or less or even in bacterial mulm as the bactria involved use up the oxygen in a given area and then turn to the oxygen in nitrate, leaving N which forms N2 gas and bubbles out. These bacteria also use some N via assimilation.. Deep sand beds are nice for animals that may need them but aren't needed for denitrification. Some like the aesthetics of a deep sand bed and the worms and such that live there. Some just learned to do it that way . A well functioning dsb will process detritus nicely too.. I like the beachy look and use an inch or so of sand with sand pools for wrasses that need to bury themseves at night.
High flow sps tanks can be a challenge with sand ;it can blow all over. I you are careful , you can arange high flow and aquascaping to accomodate a beachy look and some sand for surfce area for the benthic heterotrophic bacteria that perform denitrification. If you don't want the beachy look and dont plan to keep critters that need sand ,then bare bottom is fine as long as you have some surface area for the bacteria somewhere in the system.