DIY Nitrate filter?

[nfored]

40ppm is not "bad indeed". Ideally nitrates would be 0, but that is not possible for most fish keepers. I've heard of nitrates of over 100ppm in tanks where fish were flourishing and breeding for years and years.

While elevated nitrates can cause issues with fish, especially the more delicate ones, if you can keep your nitrates at 40ppm or below, you're doing a pretty good job.

** I'm not saying that you shouldn't strive for the lowest nitrates you can get, but saying they're "bad indeed" is spreading misinformation about the effect nitrates will actually have in the aquarium, imo.

Also OP I also don't think this will work 3.5gph is slow, but I don't think you will have enough bactera to remove all the oxygen before it gets to the bio media where the nitrate hungry bactera would grow.

I am challenging you to a race to Drop the Nitrates I also have 40ppm and doing my own 6 week test. FYI denitrate coils take weeks if not months to become active.

 

[Danger_Chicken]

I'm not sure this idea will work. You have a lot of the basic's of a denitrator but you're missing a few elements. Mainly, food for the anaerobic bac. Anaerobic bac doesn't eat nitrate, what it does is break the nitrate molecule apart to get the O2, leaving nitrogen gas to bubble off.

A coil denitrator was mentioned, this is probably the most common type and easist to build, my understanding of these is weekly you have to add sugar or vodka to the filter to feed the anaerobic bac.

Another type is a sulfer denitrator. Your build sounds similar to one of these (pictures would be helpfull). I've built these and the results were amazing. I used an aqualifter to supply the filter and an orp meter to see O2 levels. It took about a week to deplete the O2 in the filter and for the bac to colonize. I tested everyday, no change in nitrates then on the 5th or 6th they dropped to zero - form over 100ppm. This was on a test 5g tank. The sulfer pellets are the food source and matrix for the media. The problem with this design is the effluent PH is around 4.5, I had ideas to correct this before reaching the tank but the project was selved for lack of time. I hope to pick it back up in the fall.

I don't understand why yours is submerged and using an aqualifter, or the holes around the top. For a dinitrator to work you have to deplete the O2. Even running a low flow aqualifter I put a valve on the effluent end to limit the flow to .5g an hour. The trick with this type is tuning the flow to maximize the dinitrafication while controlling the O2 level inside the filter. Any more then a few drips a second (while cycling) and you're putting to much O2 through the denitrator. Also to note, you don't want it too slow or it will create hydgoen sulfids (I think that's what it is, I can't remember). I've heard of other's taking several months to cycle but managing to get a steady albeit slow stream from the return. This low flow will work on large tanks. The denitrator will reduce the nitrates faster than the BB can produce them and over time bring the tank to zero. Mine was desinged for a 220g.

 

[Richies^Ghost]

The folks over at Seachem seem to think this idea works - they provide a substrate for it (basically small matrix, so that it compacts more I guess) and advise that it be put in a filter wil a slow turn over (I forget how much however). They don't mention anything about feeding it however.

 

[Windsorguy77]

Here is a version of one for a saltwater setup. I don't see why it couldn't be used for fresh or salt. Just need some sort of bio media inside.

http://saltaquarium.about.com/od/diydenitratorplans/ss/sbscoildenitrat.htm

 

[Richies^Ghost]

Something interesting I read was that nitrates reduce oxygen uptake in the blood stream - this results in suffocation in mammals, but fish have greater tolerance. They suffer ill effects however, such as cell death at the extremeties - also known as hole in the head syndrome.

 

[Danger_Chicken]

The folks over at Seachem seem to think this idea works - they provide a substrate for it (basically small matrix, so that it compacts more I guess) and advise that it be put in a filter wil a slow turn over (I forget how much however). They don't mention anything about feeding it however.

What they are suggesting with matrix isn't a denitrator (filter) but media that has potential denitrafication capabilities when used in a common filtration systems. A denitrator is a completely different environment.

There is a lot of speculation on how well matrix works in regards to reducing nitrates (or if it does at all) when used in a canister or w/d. I love the stuff as bio media; in the canisters I use it in I haven't done controlled before and after tests to see if it has helped with nitrates.

Something interesting I read was that nitrates reduce oxygen uptake in the blood stream - this results in suffocation in mammals, but fish have greater tolerance. They suffer ill effects however, such as cell death at the extremeties - also known as hole in the head syndrome.

That's interesting about the cell death. Nitrates causing hith is speculation, no one really knows what causes it exactly. High nitrates seem to play a part to some extent, but so does diet. Nitrates may just agitate hith and have nothing to do with the the initail formation; or, maybe one day we'll find out they are the sole cause. I really wish science could figure this one out.

 

[Richies^Ghost]

What they are suggesting with matrix isn't a denitrator (filter) but media that has potential denitrafication capabilities when used in a common filtration systems. A denitrator is a completely different environment.

The product I'm referring to is called "Denitrate" and looks very similar to Matrix, though in smaller pieces. Seachem claims:

For best results, de*nitrate™ should be placed to assure the flow of water through it, such as in a canister filter, chemical filtration module, or box filter. Flow rate should not exceed 200 L (50 gallons*) per hour. If higher flow rates are unavoidable, use Matrix™ or Pond Matrix™. It is best to rinse off dust before use. Once de*nitrate™ has been in use for several days, nitrate concentrations should start to fall and level off gradually at a concentration of about 4–5 mg/L as nitrate. As long as nitrate concentrations remain under control, the product is not exhausted. Each 500 mL of de*nitrate™ treats about 100–200 L (25–50 gallons*), depending on initial nitrate concentration and the current biological load. Enough should be used to remove nitrate at a rate at least as fast as the rate of formation. If very high nitrates are initially present, they should be brought down to less than 20 mg/L with water changes.

http://www.seachem.com/Products/product_pages/denitrate.html

 

[Danger_Chicken]

I do love Seachem, but keep in mind you're reading the manufactor sales literature.

I'm not disagreeing with you or Seachem; however, they are talking about using this media in standard setups to get nitrate reduction, not an O2 depeleted denitrator filter like the OP built. I can see how that would work just like live rock.

 

[Wet]

[FONT=Times New Roman, serif]I mentioned this in another thread, but duckweed can be a simple solution. Either by taking your “waste water” and putting it in another container that receives daylight then cycling it back to your tank, using it in something similar to a sump, or having it directly in your tank. It is very effective at scrubbing N out of water including raw ammonia. Even with the best cycled tank nitrates still need to be removed by water changes unless you have plants to consume it. For anyone interested here is some good reading; http://www.fao.org/Ag/AGAInfo/resources/documents/DW/Dw2.htm[/FONT]