Tank size, sand depth and questions

carpet1

I have to say that saltwater tanks can get into your mind and consume you. Here is my deal. I have a 58g that I have live rock, 4" of sand, and a temporary hang on skimmer until I finisf my sump this week.
I also have an old 100g oceanic tank, stand, and stuff that now has freshwater fishes in it. Doing good, just not very interesting. I have given thought to starting a saltwater tank using the tank, stand, etc. Question one, I have read that 1" of sand, or at least 4" is desirable. Why? If I was wanting to, over a long period of time [I am learning patience] thanks to Pasfur and others, build a reef tank, which sand depth would be best, and why. Thanks in advance

onefish2fish

less then 1 inch or 4 to 6 inches of sand, not crushed coral. anything over an inch and under 4-6 will trap food, detritus and debris causing issue with nitrates, crushed coral serves the same idea as things get stuck between the large gaps the crushed coral creates. you also wont want sand thats of to small of a grain size as the powerheads and flow in the tank will create a sandstorm. a 4 to 6 inch undisturbed sandbed is ideal because it allows de-nitritfying bacteria to grow benefiting the tank.

Tyyrlym

Is there any benefit to laying down egg crate in the bottom of the tank to aid in keeping the lower levels of the sand bed undisturbed?

Pasfur

Great question, and very controversial! I personally do not, but I believe OF2F does. At this moment in our understanding of deep sand bed biology and chemistry, I do not think there is a correct answer to this question.

However, you do not want to raise the sand bed using a plenum, as this creates a completely different scenario. Plenum systems and Deep Sand Bed systems are entirely different monsters. But just laying down egg crate for added stability may not cause any harm, and may or may not help.

Tyyrlym

Well I was looking at it for two reasons, a solid foundation for live rock and it's ability to keep the very lowest level of the sand bed undisturbed. In retrospect you're talking maybe half an inch of sand in the egg crate so it's benefit probably isn't much in a 4 to 6 inch DSB.

Pasfur

I agree. I would like to hear more from OF2F as to how he incorporates the egg crate. (Assuming that he does, my memory could be wrong.)

I think egg crate is probably most beneficial in systems with a 1'' or less sand depth to help stabilize the rock structure. Personally, I use cable ties to attach my live rock pieces together. After the display is complete the entire structure is very solid. In a few short months the coraline algae that grows also acts as a sort of glue, holding the pieces together unless significant pressure is applied.

onefish2fish

my last tank had eggcrate under the sand. if your going with very shallow sand i suggest this method because its safer if your rockwork decides to tumble. having a 4 - 6 your lower levels of the sandbed wont get disturbed much if at all with or without eggcrate. sand shifters will only stir the top few inches.

Tyyrlym

I want to go deep and get the benefit of a DSB. It will also eat up some of the 55 gallon's excessive depth.