# DIY Coil Denitrator (Step by Step walkthrough with pics)



## elgenyo (Feb 26, 2004)

I am going to try to demonstrate step by step how to create one of these bad boys. I've always wanted one and since I am planning a new 100gal Tang tank in my office, I want one up, running and cycled ahead of time.

This is what you'll need!









Lowes shopping list!

$3 - 4" S&D PVC pipe (non schedule 40) got a 10' piece on clearance because the end was cracked
$9 - 75' 1/4" tubing (get more as 75' just fills the pipe and you'll need some for plumbing)
$3.34 - 4" S&D cap X 2








$.33 - 3/4" tee
? - 3/4" ball valve I had laying around
$.46 - 3/4" to 1/2" adapter








$16.64  qty of 3_1/8" Barb x 1/4" MIP(I'm sure something else could be used but I was in a hurry so I grabbed what I knew would work)
$4.36 - qty of 2_1/4" brass coupling
$4.12 - 1/4"x1/2" compression coupling

TOTAL
$41.22


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## elgenyo (Feb 26, 2004)

Now that we have the parts lets get to building this thing!

1. Cut the 4" PVC pipe to 24" (I used a saw but I imagine you could use your teeth if you don't have a saw around)
2. Insert the airline tubing into the pipe _(This is where most people will quit because I almost did. My recommendation is to wrap the tubing around the outside first so it takes the general shape of the pipe then insert it using both arms, one in each end. Use a clamp to keep the starting end in place. This will allow you to keep torque on the tubing as you wind it tight along the inside wall)_
















3. Once finished clamp the end piece so it doesn't unwind on you.
4. Fill pipe with sweet bacteria condos of your choice (I used scrubbies, good luck finding them)








It took 24 pads to fill it to the top.









Set this piece aside as we will now start on the top cap. Don't forget to clamp that end piece because it will unravel on you!


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## elgenyo (Feb 26, 2004)

Forgive me on this part as my camera settings were changed for photographing fish and these closeups of the pvc pipe came out way too bright. I'll try to compensate with detailed description.

5. Get out a drill and a universal bit.








You'll use this to drill the inlet and outlet holes on the 4" cap. So I wouldn't drill holes too big for the 1/8" barb adapters to fit, I traced out the bottom of the adapters using a sharpie.








Again sorry for the brightness! Once the "threaded" end of the adapter has been traced out on the cap take your unibit and slowly drill out the holes being careful not to exceed the trace lines you made. I drilled mine just large enough to where I could screw my adapter into the cap creating a tight seal.








6. Flip the cap over and use plumbers tape around the threading of both adapters. 
7. Place a 1/4" brass coupling on both. Tighten the couplings to the adapters using wrenches. Mine were tight enough that leaks were not a concern in this low pressure application.
8. Place the third 1/8 barb adapter on the coupling mated to the inlet, again using tape on the threads.
9. Grab the pipe that we set aside ealier. Attach the airline tubing to the inlet barb. Use PVC primer and cement to secure the cap. Voila! Hope you didn't forget anything because its sealed tight now!


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## elgenyo (Feb 26, 2004)

Let's give this thing a name!









10. To attach it to your setup will differ depending on pipe sizing and such. My return plumbing is 3/4" pvc so adjust according to your setup.
11. Attach 3/4" tee to 3/4" ball valve using 3/4" pvc, primer, cement.
12. Attach ball valve to 3/4" to 1/2" pvc adapter
13. Screw on 1/4"x1/2" compressions coupling
14. Attach airline tubing to the compression end and run this into your sump










*Finished! *


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## booba5 (May 3, 2008)

que?


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## iceblue (Apr 27, 2004)

Could you give us an overview of the path the water will take through your denitrater?


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## elgenyo (Feb 26, 2004)

Its the same as the other DIY Denitrator plans out there. The water enters at the top via the airline tubing travles 75' and exits at the bottom filling the chanber with scrubbies and pushes its way back out of the denitrator via the airline tubing connected to the exit going into the sump.


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## prov356 (Sep 20, 2006)

Here's a link with some description. Here's a thread that I'd suggest reading too. I"d be careful about implementing these unless one has studied up and understands the principles behind them.


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## KaiserSousay (Nov 2, 2008)

I like it  
Thanx for the walk thru :thumb:


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## Terry_Teater (Aug 4, 2009)

:fish: I was wandering you have the power head from you sump pushing water into the inlet, the water goes through the wrapped tubing, the water exits out of the tubing into the base of the cylinder, that is when the sponges/bio balls plays it part, then the water gets pushed out of the outlet hole back into the sump, is that right? I'm considering building me one.

I have a 100 gal predator tank, one 4" clown trigger, one 4" undulated trigger and a 14-16" eel, I have 80-90 lbs live rock, pumping 700 gph, two 1200 gph waver makers, two 1300 gph wave maker, coralife super skimmer,coralife uv, 15-20 gal refuguim with 130 watts reef light (12-14 hrs per day). Salinity 1.025-6 ph 8.2-8.4 Ammonia 0, nitrite 0 and nitrate 20-50. I do 25% water change a week and one 50% a month. I have a RO DI pump.


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## planenut007 (Mar 21, 2009)

WOW! Gonna have to look into this one when a few less crown and ice's are involved, will do some research.
Again, I say the water is the most interesting part of the hobby(sickness).
Any cleaning involved?


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## TNprogrammer (Jul 28, 2008)

Prov, I read your link. VERY informative. I was wondering what part the long tubing played and it was clearly explained. I think this is definitely worth a shot. Especially for the price. I have 4 tanks in my house now, and water changes do not get done as regularly as they should. I don't expect this to eliminate water changes by any means since I want my fish to have nice clean water regardless of whether or not it has nitrates in it, but it could give me an edge on keeping my water quality as pristine as possible BETWEEN those changes.
Can I use this WITHOUT a sump by just running the intake and output tubes straight into my tank right beside by canister filter tubes?


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## Stickzula (Sep 14, 2007)

The danger with using them without a sump is the potential for hydrogen sulfide gas getting in the tank. The denitrator has the potential of producing this gas, however, it can be dissapated by airating the water. This is easily done in a sump. Essentially, the water comes out of the denitrator with hydrogen sulfide in it. Then the water goes into the sump and mixes with the water there and both are exposed to air. Theoretically, by the time the water gets back in the tank the hydrogen sulfide is gone. By letting the denitrator drip directly in the tank, you eliminate the opportunity for airation and increase the probability that hydrogen sulfide will enter the tank water.


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## warbyd (Apr 3, 2009)

If the output from the denitrator is only a very slow flow though, if it were directed into an area with alot of agitation (eg directly above an airstone or powerhead) would this be sufficient to allow the gasses to vent?


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## Terry_Teater (Aug 4, 2009)

I just finished making mine, I did 22 X 4. I am going to hook it up tomorrow and see what happens. Its cost about 50 bucks to build and I had to buy a maxi jet 600 which was another 31. I used the pre coiled tube from wal mart. I used all plastic fitting ( brass has copper into which can harm fish/plants). I'll do a up date when I get it up and running. If anyone has any questions about building one, just ask.


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## vaypourus (May 20, 2008)

It is really super important that the water you pump into this is at least run through a pre-filter to remove larger particles. That small tubing can get clogged very easily once you have ample bacteria colonies built up inside of it!

A reefer I know tried this and ended up having some issues with it going toxic. He had much better results (in terms of both tank safety and nitrate removing performance) using an algae scrubber.


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## ccla (Feb 2, 2009)

I am thinking of building one of these. The problem that I have is that my tap water comes out with a 20ppm Nitrate level and that makes it very difficoult to keep Nitrates below 40ppm.
I understand the theory behind the whole process but I have a few questions;

(1) I read somewhere that the flow has to be carefully controlled. Is this because if the flow is too fast, there isn't enough time for the aerobic bacteria to consume the oxigen?
(2) How do you control flow? On the inlet or on the outlet line?
(3) How do you determine when you achieve the right flow?
(4) Is any smell released by the filter if properly set-up?
(5) About the problem with toxicity, do you have any warning that there may be a problem, or will you wake up one morning and all of your fishes will be dead?


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## Terry_Teater (Aug 4, 2009)

Hey ccla,
Your questions:
If your tap water is 20PPM, I would recommend buying a reverse osmosis pump. You can hook it right up to your kitchen sink and it will remove all the impurity's from the water, you can purchase one from ebay for less than $100, just remember more chambers the better but a two chamber will be fine.
You want to control the out flow, if you pump it out to fast you will not grow aerobic bacteria, to slow you will get a rotten egg smell (not good). You can get a ball valve from your local hardware store under $5. You want the out flow to have a drop a sec for the first couple weeks, then go to two drops a sec, you will have to do regular testing to see what you need to do. Also watch your PH, I have heard of these pumps stripping your PH really low and causing tanks to crash. 
As far as toxicity, do you have a sump or will it be running straight into the tank? I have mine (saltwater) going into my sump, as the water exit from the coil denitrator (has no oxygen in it), it returns to my sump and my sump puts the oxygen back into the water before it goes back into my show tank. You really will have no signs other than egg smell, when you have evaporation it removes the chemicals out of your tank. I hope this helps! If you have any other questions feel free to ask. :fish:


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## Stickzula (Sep 14, 2007)

I would so something to re-oxygenate the water prior to letting it in the tank. If you can't do it through a sump, I would try to design an inline chamber that could aerate the de-nitrated water before it gets to the tank. Also, a gate type valve is much more sensitive than a ball valve so it is easier to get the right flow out of it. If it were me, I would put a little extra money into a gate valve.


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## Stickzula (Sep 14, 2007)

Something like this might work.


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## ccla (Feb 2, 2009)

Thank you Stickzula,

the only question I have is where will the air pumped into the chamber escape to?


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## vaypourus (May 20, 2008)

In that diagram, there is no air going into the filter. The air is being pumped in after the coil exit.


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## Stickzula (Sep 14, 2007)

The air enters the "line out" after the denitrator and escapes the system when the water enters the tank. If you don't want bubbles in the tank, you might be able to make an air letoff at some point between the air chamber and the tank. I don't know what that would look like at the moment, but I'll give it some thought.


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## Terry_Teater (Aug 4, 2009)

Just make sure that oxygen stays out of the chamber it self! I have mine going directly into my sump for oxygen first then into my show tank.


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## Joephish (Oct 28, 2005)

Do you "feed" the denitrator sugar as recommended in one of the links? If so, how much and how often?
How much water do you run through this unit? (ie: gal/hr or drops/min etc.) I imagine that if it's too fast, the O2 won't get eaten up in the coil.
This seems like a great idea. How often do you have to change your water with this system? The main reason that I have heard for water changes is to get the NO3 out.
I am also wondering how often the unit needs to be cleaned out. It would seem that the bacteria would continue to reproduce and clog the system at some point. It might take years though.
Thanks for the step by step. You explained it very clearly.


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## ccla (Feb 2, 2009)

Stickzula said:


> The air enters the "line out" after the denitrator and escapes the system when the water enters the tank. If you don't want bubbles in the tank, you might be able to make an air letoff at some point between the air chamber and the tank. I don't know what that would look like at the moment, but I'll give it some thought.


Hello Stickzula,

I know the oxygen must enter in the output of the denitrator (it would be kind of useless to oxigenate the water before the denitrator  ).

My mistake was in assuming that you oxigenated the water before the valve. I should have taken a closer look at the diagram.

Thank you. I think this weekend I will start taking a look at how much it will cost me to put all of the parts together. Also, I am thinking of making the top of the unit screw on somehow to be able to open and clean it occasionaly. Of course that might add to the costs and might force me to somehow "glue" the coils inside so that they do not come apart when I open the unit.


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## Terry_Teater (Aug 4, 2009)

I just built one about three days ago, the total project cost about $62. The power head was $27 by its self. The first two weeks you need to set your unit to 1 drop per second. Then you can adjust to 2 drops p/s at week three and four. Watch your PH, I have read that this unit can make your PH to drop/even crash your tank. Make sure you do regular test. The unit will take about three weeks to see a nitrate change. The first couple weeks your nitrate will go up 10pp(cycle period), then they will start to drop slowly (be patient). You do not feed this unit anything!!!!. This unit is made so you do not have to reopen for any reason and it is self maintained.


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## ccla (Feb 2, 2009)

Terry_Teater said:


> Watch your PH, I have read that this unit can make your PH to drop/even crash your tank. Make sure you do regular test.


I wonder if it would help to replace the scrubbers with Aragonite. This should may help prevent a ph crash? I saw this used in commercialy made denitrators, but those are not of the coil type variety.


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## purkruins (Dec 18, 2010)

elgenyo said:


> 6. Flip the cap over and use plumbers tape around the threading of both adapters.
> 7. Place a 1/4" brass coupling on both. Tighten the couplings to the adapters using wrenches.
> 10. To attach it to your setup will differ depending on pipe sizing and such. My return plumbing is 3/4" pvc so adjust according to your setup.
> 11. Attach 3/4" tee to 3/4" ball valve using 3/4" pvc, primer, cement.


I agree with you elgenyoa, The turn plumbing is 3/4 to make it the size is on it proper setup. The 3/4 is the beset size that suits it well. And, it would be PVC to make it easier and fit into its material.


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