Substrate in Fuge

[HerbieK]

I was wondering what kind of substrate people are using in their fuge. I am looking to potentially create a deep sand bad to promote denitrification. I am using a 20 gal high as a fuge, which will contain some rock rubble and chaeto.

Let me know what kind of fuge setup you are running, pros/cons, etc.

Thanks.

Herb

 

[Treadingwater]

That's what I have in my fuge and for the same reason your looking to do it. I don't like a DSB in the main tank, so this set up allowed me to keep the bed in the tank shallow and still get the benefits of a deep bed. My sand bed in my fuge is about 5" or so deep with some live rock and cheato. So far it seems to be doing good, but my tank is still fairly new.

 

[Carlo]

If you already have the 20H then that is fine to use but a better choice would be the 20L. The reason is that you have more surface area for the sand and end up with a "bigger" DSB. You can have the water enter one end and exit/overflow the other end.

Of course if this is going under a stand and space is an issue the Long may not fit. You also may need to have the drain and return on the same side of the tank too because of space issues. The main thing is to try and make sure you have some circulation in the fuge tank but not a huge amount like the sump area.

4.5" to 5" seem to be an ideal depth for good denitrification. If you are going to add the rock rubble pile it up on the side of the tank and try not to cover the sand. If you create a pile the pods will like this. If you scatter it across the sand bed then the Cheato will get stuck on it a lot. You'll end up getting Cheato debris stuck on and under the rock. It won't "tumble" and the bottom layers will die off from not enough light and it will break down and release nutrients back into the tank.

As far as the subtrate goes, ideally you want a mix of different size grain sands all mixed together (no layers). Don't worry about buying "live sand". The "Live sand" you buy isn't that good for denitrification purposes anyway. Once setup the DSB will take anywhere from 3 to 8 weeks to develop.

Carlo

PS Contrary to popular "DSB rules" I disturb my DSB on purpose. I keep a little magnet on my tank to "mark" my position. Every couple of days I reach down into the sand and mix or flip the sand around (bottom to top) and do a few inches worth. I then move the magnet so I know where I left off for next time. Doing this in small batches helps to keep the sand clean long term. Since I don't do that much at one time I don't disturb the overall denitrifing ability of the sand bed. Doing this regularly and you won't release anything harmful either.

 

[mladencovic]

PS Contrary to popular "DSB rules" I disturb my DSB on purpose. I keep a little magnet on my tank to "mark" my position. Every couple of days I reach down into the sand and mix or flip the sand around (bottom to top) and do a few inches worth. I then move the magnet so I know where I left off for next time. Doing this in small batches helps to keep the sand clean long term. Since I don't do that much at one time I don't disturb the overall denitrifing ability of the sand bed. Doing this regularly and you won't release anything harmful either.

That is the role of sand sifting stars, nasarius snails, worms and sand digging gobbies and crabs

p.p.s Don't use the stars in such small space/surface and gobbies if it is a refugium.

 

[Carlo]

That is true of the inverts but I prefer to keep the refugium free of fish and crabs. Gobbies and other fish (normally) don't belong in a refugium IMHO. The gobbies will eat your pods big time. This is just my opinion and I know other people feel differently. Without a predator in the fuge it can supply a nice population of pods to the display tank. I keep Mandarins in the display tank so maybe I'm biased because of that.

I think if you are careful as to what you put in the fuge you can be alright but you don't want any predators to what you are trying to grow/populate. I myself prefer the "hand dip" a few inches every couple of days which will do more then any invert/fish will to keep the sand clean and I can control it. Takes all of 10 to 15 seconds to do.

Carlo

PS the main reason I do it myself is so that I know it gets done. I never have to worry about a DSB crash 3 or 4 years down the road.