High Nitrates - Replacing Sandbed...?

[stephencraig]

I'm not sure of the actual model. Its one that sits cross ways in the 30g sump. I have a big Euro-reef that I have on the other tank that will be big enough for the larger tank when I combine them. One of the reasons I have not upgraded the Tunze. Also space would be an issue. If I run across a good deal on a used one, though, I might consider changing out the skimmer too. I'm trying not to buy anything that I can't use when I move these two tanks into the larger one.

Stephen

[Jeff]

check the flow going into and around the rocks.to much rock can trap detritus and cause you to have a constant supply of nitrates. i was fighting cyno for awhile and after i removed some of my rock and reaquascaped the cyno went away. if you can post a picture of your rock work.

[LoneStar]

Now this might not be a solution for NOW but when you upgrade to your larger tank, you can aquascape your rocks onto PVC racks and then position powerheads behind them to constantly clear the detritus they build up. Then if you have good flow and a good skimmer, you should be able to take most of it down to the sump where your skimmer should clean it up.

Here is a version of what I was saying. It does not have the PVC racks but it did use a 'plastic dam' and egg crate to allow access for a pump to blow away the detritus and keep the sand from coming under the rock. The photos were taken off a build on ReefCentral. A Deltec tank

And here is how the rock looks stacked over the crates:


And here is the thread where I found the photos:
http://reefcentral.com/forums/showth...hreadid=880909

Its easy and fairly cheap. If you do not have a closed loop, powerhead could work too. I would build a small PVC 'table' and position the rocks on top of it.

This is just a small way of PREVENTING nitrates. Like stated before, its just a matter of how big your bio load is in your tank vs how fast your tank can clean them out. So if you run a RDSB, effecient skimmer, fuge, lots of flow to keep detritus suspened in the water column (so the skimmer/filters can trap it) you might come ahead on the battle ;)

Since you are sticking with sand, I would also agree that the RDSB will be your cheapest route. Just get some cups of sand from a few memebers here to seed it.

[erikharrison]

holy crap! I need to build up my sand too! Mine is about 2-3 inches as well, so I guess I gotta go spend about 30 dollars for another bag of sand? CRIKEY!

[stephencraig]

Here's a pic of it today (still learning how to use me new camera). Not sure how much this helps.

Stephen

[stephencraig]

Thanks LoneStar. This is very interesting stuff. I had wanted to build the new one with "something" in it that you could blow stuff out from behind the rocks. This might the answer.

Stephen

[stephencraig]

Lonestar, Does the grate support the rock, or does something else support the grate (where it would have flow under it), which supports the LR?

Stephen

[LoneStar]

Lonestar, Does the grate support the rock, or does something else support the grate (where it would have flow under it), which supports the LR?

Stephen

I'm not sure really. I have not run across that many Deltec tanks. Probably because they are sooo expensive. Either Deltec used regular egg crate or they have some expensive stuff they came up with that allowed flow underneath.

If you stick with sand, I would have some sort of acrylic 'dam' that will skirt around the diameter of your rock structure. Then you can build a small pvc stand to support the rock. Depending on if you use a powerhead or spray bar you can go in either direction. If you use a powerhead, just make sure you can retrieve it somewhat easily for cleaning ;)

I know some people actually turn their pvc rock stands into spray bars (adding loc line fittings to spray under and in the middle of the rock) Of course it will be connected to a closed loop.

Hope that helps!


Or just go bare bottom and get a kick ***** skimmer! :P

[Thunderkat]

I had a 7" deep sand bed in my old tank with a plenum in it and about 10 nassarius snails in a 75 gallon tank and didn't have a problem with nitrates. I also had a 55 gallon tank as a fuge with live rock and macroalgae growing in it (that was excessive, fuge does not need to be that large) with 24/7 lighting and didn't have a problem with nitrates. I have read that oxygen levels can drop very low overnight in tanks with plenums so I added the fuge with macroalgae and lights. If you get everything set up properly a good sand bed can take care of many problems but creates new ones such as excessive coralline growth (yes it is a problem when you are scraping it off your glass all the time).