Okay, I know that trickle filters and canister filters produce a lot of nitrate in a sw setup. Why is that? And, if that's the case, then why do people buy those filters to start with? It seems to be recommended in many books. I am just missing some point here, fill me in...thanks.

------------------
I am Seaman: The Forbidden Pet

its not so much the entire trickle filter, its more like the Bio balls it uses, they tend to get clogged with Dissolved organic matter thus creating nitrates.

------------------
My 180 Utopia: Updated 5/21/00

I think that most of the info in books is a few years behind. I was one of the people who had a trickle filter and no sand bed in the early 90's. It's been sitting in a closet for the last 5 years. I switched to a deep sand bed and never looked back. I do think that trickle filters are still usefull for fish only systems.Bob

------------------
Visit my web page: http://bobsreefermadness.homestead.com/index.html

Seaman
Just the short version. Trickle filters, with any media, are very efficient at converting ammonia to nitrite then to nitrate. The problem comes from the inability of the media to produce the bacteria which convert nitrate to a gas. The needed bacteria can only flourish in areas of very low oxygen and low light. Not the case in a trickle filter. With lr and deep sand bed the outer portion builds the bacteria (aerobic bacteria) for the ammonia to nitrate breakdown and the inner portion builds bacteria (anaerobic bacteria) for nitrate to a gas Which is often seen as bubbles working their way to the top of a sandbed and eventually floating to the top of tank.
hth
Scoly

[This message has been edited by scoly (edited 06-03-2000).]

Scoly pretty much hit the nail right on the head. Thats why the search for a denitrifier in the days of wet/drys since these are very efficiant at breaking waste down but lacking the low ox areas for reduction of nitrate into nitrogen gas. Hence elevated nitrate levels and need to do frequent water changes
As they say "The solution to Pollution is Dilution". One of the trends I seem to notice with the deepsand bed/live rock crowd is some people feel that since nitrate isnt building up its not neccessary to do as many water changes. Personally I think its flawed logic and still change 8 gallons weekly, even though my system is about 70g total with DSB LR and skimmer, I drip Kalk 24/7 and supplement with B-Ionic. I also use DT's phyto and feed homemade reef mush heavily

------------------
Reef as though your life depended on it, yours might but the seas does Doug TheReefTank admin

Thanks for the replies. I am coming to a closer understanding with how the nitrogen cycle works in a SW environment. But, not close enough. Anyhow, I'm not done reading books yet, so let me sort of "skip" ahead and ask you this question: What do you guys recommend for a reef system? Will this work: About 3" of aragonite sand, 1" of LS for the substrate; a protein skimer, and some type of filter for mechanical (recommendations?). Thanks.

Okay, okay...after reading Scoly's post a couple times, I am considering using a sump with LS and LR (?)...will this work instead of using bio-balls?

I too am one that has used bio-balls, and they are now what I believe to be the cause of my nitrate problem. I am slowly removing them to try and reduce the nitrates. I currently use a 3" deep bed. If after the balls are removed this isn't enough to make the conversion, I will add more LS, at least another 2".

reef,
Do you plan to put the LS in your sump or directly into your tank? I would think the sump. But, let me know. I'm also wondering when you have LS as your substrate, do you need any circulation going through or passing the LS? This is cool, I feel like a born again beginner.

------------------
I am Seaman: The Forbidden Pet

I always feel like a beginner in this hobby [img]/ubb/embarass.gif[/img]!

I am not sumped, so the only LS is in my tank. However, I was considering adding about 10 additional pounds to my Wet/dry and covering the system so it would be dark. The only reason I haven't already done this is because of my return. I would have to place a pice of plastic between the sand and my pump, so it wouldn't get clogged.

Another option I am going to look at is LS were my bio-balls are/were. I think this would be a good place to utilize the benefits of the LS, and at the same time take up empty space. I could allow the water to trickle on the LS (of course it would be completely underwater) and then let the water overflow into the area for my pump to make it's return. However, these were just some things I have been tossing around.

Back to your question, I do not have circulation (i.e., UGF) passing through my sand, but quite a bit of circulation blowing over it.

Using a ugf below the live sand will reduce the possiblilty of anaerobic bacteria. One of the requirements for this bacteria is a low oxygen environment. Just putting it on the bottom and allowing water to pass over it is all that is necessary. Have seen recommendations of 3 to 6 inch bed. In a sump or on the bottom of the tank will work fine and in the bottom of a wet dry without the media is nothng more than a sump.
Good article on the makeup and organisms of ls: http://www.reefs.org/library/talklog...ek_090698.html
hth
Scoly

An alternative to BioBalls are shotgun shell wads. They will do the same as the bioballs but don't seem to keep debris like the balls.

I used to use bioballs in my trickle and had the seem high nitrate levels. Then I was advised to try the wads. Well... I can gladly say I have a 1 inch bed, and no nitrates! After switching about 1 year ago.

It may be worth a try.