How much substrate do I need?

[Siddique]

Hi all, I'm gonna be setting up my very first reef tank in a few days time and I needed to know from a professional's point of view, how much pounds or what depth of live sand will I need for a tank that measures 36" by 18" by 18". I have an estimate of about 4" of sand because that is what I have in my already established fish only tank. However, in the initial setup of that tank, I only used one inch of live sand and the remainding 3" with ornamental sand (I don't have a clue what the propper name for it is) the crushed coral type. Can i do this same process with a reef tank or do I need a full bed of live sand?

[coral reefer]

Just like you have in your fish only tank. I would go with 4-5 inches of aragonite sand. It doesn't have to be live sand either as that is usually more expensive and you would get better results anyhow, by just taking some established sand from your fish only tank to seed your reef tank!!!!!

[Siddique]

Yea I was concerned about the cost of using 4" of live sand lol...I guess I'd do that then, there's alot of sand in the fish only tank so it won't hurt to steal some... Thanks fo the advice

[Jason McKenzie]

I just put 1.5 inches in my new tank. I will have to clean it and it will not be used as a denitrifyer but I wanted something. There is a great calculator here
Sand Bed Calculator

J

[Blade_Runner]

That really boils down to how you plan on filtering the tank. Specifically how you are denitrifying the tank. i.e. If you have a large sump, you could put 3-4 inches of sand in it and put no sand (bare bottom) in the show tank. I personally don't think any more than 3" is necessary. Depending on who you talk to, I hear that you get anaerobic activity in as little as .5" of sand. There are a lot of positives to a bare bottom setup. I just don't like the look. I went 1/2 way there on my 300. I have about 125 pounds of sand in the tank to cover the bottom and about 200 in one chamber of my sump.