MY DIY Coil Denitrator

[Stipe]

Hey guys,

After a bit of reading i decided to give it a shot. Hey what do i have to loose. After a short trip to the hardware shop and some of my free time i made this little gizmo.

Lets get the basics out of the way first. Firsts THIS SYSTEM DOES NOT REQUIRE FEEDING!. So suck cr@p to all the other commercial brands who's maintenance require almost daily feedings to the bacteria.

Ok all i coil denitrator is, is a pvc tube with piping wrapped around the inside of the pvc tube in a spiral shape. "The water slowly works it's way down the spiral, the O-2 is consumed by the AEROBIC (living only in the presence of oxygen) bacteria, the same ones that are in your filter and make all the life possible. Somewhere around 3/4th's of the way down however, the O-2 levels diminish within the spiral, having been consumed by the aerobic bacteria higher up the coil. (D=Base)

Now what? Well, now the ANAEROBIC (can live in the absence of atmospheric oxygen) bacteria begin to flourish, the very ones that feed on nitrate, not O-2! As the water continues its travels it encounters the main interior chamber of the cylinder. All those bioballs are just waiting to provide area for more anaerobic bacteria to consume all the nitrate that wasn't converted inside the bottom 1/4 of coil. This is the "bank" that will allow the coil denitrator to continuously process more and more nitrate as it is produced within the display tank. " quoted from http://saltaquarium.about.com/cs/nit...a/aa092702.htm

My design is a bit different instead of wrapping the coils around the inside of the pipe, i bought a smaller pipe and wrapped it along the outside of that with two layers they placed that inside the bigger pvc pipe. This, one - made it a lot easier to assemble and two - made room for more coils. 30m to be exact.

Ok with that out of the way lets start with the show. I wont go in detail with parts but total cost for this baby was only $30Au.

Basic parts you will need.

-20-30+m (75 - 100+) of irrigation/plastic piping
-Pvc pipe or any length to fit your stand/room. This must be minimum 4 inch wide.
- caps for both sides of pvc
-pump
-flow valve


Ok i wont go in detail with constructions, but i will give captions to the pictures.

First all my equipment ready to go.



Cutting my pvc to size for my tank.




I left a little extra pipe so i can turn it into the intake/ output on either side and began wrapping. THIS IS NOT EASY. Thats because i had to wrap it as tight as i could so that the piping could blimey fit into the pvc with a double layer of pipes. this meant i had to apply pressure to the tubes as i laid it. God my fingers where killing after that

[Stipe]

After the first layer was done i started the second. You can see my lunch on the table. This look me two hours to do. I woudl rather do it eating lunch and watchign tv then in a dull garage .





after all that was done i made holes for intake and output





Insert it into the bigger pipe, it was abit of a tight fit but i got it in.




And NOW WE HAVE A GREAT WORKING COIL DENITRATOR





Ok instead of filling the interior with bioballs i used one of ehiems rock substrate thingy meant for bacteria growth. I tested everythign and managed to get the flow around 4 gallons an hour but is that too slow or not??

SO WHAT DO U GUYS THINK??

[Stipe]

Oh yah, i sprayed the pipe black so that algae wont grow inside and clog all my stuff. Because ive sealed that thing and it aint opening for another 5 years or so. : ).

Also once the pipe gets established wit bacterias ( in a month) i will test and see how well it removed my nitrates. So for my experiment after a months time i will do no water changes for one whole month to test if my nitrates currently at 20 go down.

[djmx2002]

good luck, that looks really intresting

[Stipe]

Now all i have to do is sit back and be patient ( WHICH I AM NOT, stupid thing wont work fast enought lol )

[douggiestyle]

4 gallons per hour is most likely too fast. try around 1 drip per second. that rate is equivelent to around 75 gallons per week. i ran mine wide open for the first 2 weeks then reduced to 1 drip per second.

[Pbrown3701]

what is the story on why it doesn't require feeding? Everything I've read (admittedly, not that much) says they require feeding of sugar?

[Michael Mota]

That pipe is too large for a denitrator. it may work but what you should have used was some airline or the small drip irrigation hose. Then you would set it at 1-2 drips per second. it takes about three months for it to start removing nitrates. good luck

[NanoReefWanabe]

do the bacteria just live on the sides of the plastic lines? and where if you were to put in the bioballs would they go i am a little confused on how this works...

[Stipe]

Firstly the pipe is 1/4 of an inch which is the perfect size. I just looks large in the picture.

i adjusted the flow and managed to get it to 2 gallons per hour which is alright but i will try reduce it some more.

It does nto require feeding because the bacteria will colonize on the inside of the tube over time consuming oxygen, ammonia and nitrites. About 3/4 of the way down all oxygen is now gone and this provides an ideal place for anaerobic bacteria to grow. They then start to consume the nitrates at a slow rate. Ive tried to estimate mine to around 10ppm a week, but i doubt that is accurat.

Ok it basically works by,

Water enteres from the top through the lid (the whole on the side of cap) and then travels through the 100ft of pipe till it exits at the bottom of the pipe. the water that exits at the bottom of the pipe now travels up the central hole till it hits the top and then exits through the middle whole in the cap which leads back to the aquarium.

You fill the inner layer with bioballs which provide more area for anaerobic to grow. And yes the aerobic bacteria grow on the inside of the tubes. The water movement is so slow that it provides a great environment for this to happen.

[douggiestyle]

they dont require feeding but will work better with a carbon source. sugar or vodka. that is what ive read, ive never done my own tests.

you are ok to run at 2 gallons per hour now. but you want to cut it back to about 1 drip per second. if not you can cause worse problems. that is what ive read.

[Marsfrogie]

Have you thought about using one of those airlift pumps like you use to keep a CVR overflow running instead of a normal pump? Those things pump water at a slow enough rate.

[The0wn4g3]

Subscribed !
I'm eager to see how this works out, that looks easy enough that even I could make one.

[t11t5]

I work at Eaton Corp. We make 1/4" tubing. We have a lathe that can spiral the tubing for me and then it will go through an oven, then through a cold water spray to set the tubing in the coil shape.

(example: coiled tubing between a Semi truck and trailer)

I might try to rig something up with all this at hand.....

[Stipe]

with that you could turn a 4hour project into a 20 minute (dependign on time it takes the machine to coil the thing.)

Sounds good.

I heard that if the drip is too slow then sulfur in one of its various forms is sent into the tank.

[Stipe]

Ive never heard of a airlift pump. Can you give us a link.

[beapeams]

Its called an aqualifter

http://www.petsolutions.com/Aqua+Lif...101137-I-.aspx

[douggiestyle]

Originally posted by Stipe

I heard that if the drip is too slow then sulfur in one of its various forms is sent into the tank.

actually what i read was the exact opposite.

i think you need to check into it.

BTW mine has been running for 3 years now.

[Michael Mota]

Sorry but the tubing looks large in the pic.

[douggiestyle]

i aggree michael. i used 1/4" tubing. i believe 3/8" would be on the large side. ive read where people used 3/8" to lessen the chance of clogging. ive not read anything bad. so it is only my opinion which ive based on surface area, volume and laminar flow.
so with a larger diameter tubing (in this case 3/8") you get a smaller ratio of volume to surface area (in this case compared to 1/4" od tubing, apx 4 times the volume to 2 times the surface area).

ive left out other factors but thats what ive based my therory on.

[The0wn4g3]

I'm just tagging along, but just for the heck of it. (and I could be totally wrong here)
I calculated the circumference of the 3/8in piping to be 10.67 times its area (volume, really). And the circ. of the 1/4in piping to be 15.99 times its area(volume).
So yea, seems the 1/4in piping would be a better application for this seeing as it has quite an increase in circ. to volume ratio.

just my two cents tho...

[BeanAnimal]

search for threads by RSMAN. He was a walking coil denitrator encyclopedia.

Bean

[tentacles]

I was under the impression that the tubing people were using was 1/4" OD, which would be the size you see on your ro/di.

[Stipe]

Ah yes i know what you are talking about, about the aqualift. Dont think that can withstand the pressure inside the pipe to push water through. I have a 1000LPH pump and it cant even push water through. Nothing is stuck it just pushes so dam slow, not even a trickle. So i am off to get a new pump.

Oh and the f**ken ( can ya tell im angry :P ) intake pipe started leaking bad at the cap. so not im either just gonna put some super glue as a quick ( well for me permanent cuz im lazy) fix of use some pvc glue.

about the drip rate, have a read here.

'All done, except for one last detail. A proper drip rate is needed to maintain dwell-time within the unit so the bacterias can gobble up the nitrates. Too fast a flow and your tests will show nitrites, as the bacterias have too much O-2 and denitrification isn't taking place. Too slow a drip or flow rate and hydrogen sulfides are produced, giving a rotten-egg smell that indicates trouble to the inhabitants of the reef or fish tank. I have experimented and found that a drip of just under a steady-stream is best. In other words, a very fast drip, but a definite drip just the same. Use a small air valve to regulate this on the output tube (B) running back to your sump or display tank." quoted from http://saltaquarium.about.com/od/pro...coildenitr.htm

[EnderG60]

ok two questions.

first, is the length of the tube a factor(as in would longer be better) or is 100ft/30m sufficient?

second is there a bio ball volume to tank volume ratio?