DIY Coil Denitrator Plans
 

Instructions
Examine the drawing and notice the blue shaded area within the cylinder (C). BioBalls (F). Yup, and no they aren't there so you can add another fish! These give additional surface area for anaerobic bacteria colonies.

The orange rings are the coils of plastic tubing (E) running from within an inch of the lid, down to the bottom of the unit. Once you've wound the tubing , usually 1/4", around and around inside the body of the tube, straighten the coils as much as possible.


http://img.photobucket.com/albums/v3...enitrator3.jpg


Leave the end of the coil exposed, just above what will be the base or bottom (D) of the device. Glue the bottom piece in place. A scrap of 1/2" acrylic is best but 1/4" will do. I recommend against 1/8" as it is too fragile.

base or bottom , again 1/4" will do here. For your input (A) and effluent lines (output=B) you can simply run the tubing through these holes and seal with silicone or place fittings here and use nipple connectors... whatever you like. I recommend the fittings as there will be pressure in the unit and a good seal is required. Pour in the BioBalls at this point. Keep them about 1" below what will be the top of the denitrator.

At this point you should have a cylinder (C) with a bottom, coils of tubing wrapped around the inside walls of the acrylic tube, BioBalls inside the coils and a lid with fittings or holes drilled. Attach the upper end of the 1/4" tubing to one of the nipples. Glue the lid/top on. Use Weld-On #16 thickened acrylic cement. It fills minor imperfections and sets within an hour.

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.

When finished the unit is sealed and not intended to be disassembled. Once up and running the coil denitrator will last for many, many years without any adjustments or fiddling. About the only area of attention is the drip valve. This requires cleaning periodically to remove salt crystal build-up! Cost to build this unit is around what you'd pay to BUY one through a catalog house, but where's the satisfaction in that? If you don't wish to DIY, there are several commercial units on the market that are very good and I recommend them all. The issue here is getting rid of nitrates, either through building or buying. I just like tinkering with the hobby and enjoy the challenges of DIY! Good luck, and any additional comments or questions may be directed to me, Don Carner.

About Nitrate & How This Thing Actually Works
The coil denitrator takes 5 to 6 weeks to cycle (yes, they cycle just like the tank). The quantity of product that is processed, (nitrate) is truly amazing considering how once established, there isn't anything more to do! So how does this happen? As oxygen rich water is pumped into (G) and enters the top of the unit (A) it is forced to spiral down through the layers of plastic coil tubing (E) until exiting within the center of the cylinder (C). As the water level increases within the body of the unit, the BioBalls (F) become host to the millions of colonies of bacteria's that commence multiplying. As the water reaches back up to the top, it exits through the other fitting (B), the one not internally connected that runs back to your sump or display tank. So? So, as the water slowly works it's way down the spiral, the O-2 is consumed by AEROBIC bacterias, 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 bacterias higher up the coil. (D=Base; G=Water Pump)

Now what? Well, now the ANAEROBIC bacterias 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.


what you think about this DIY and you think this will work?. any suggestion on this or opinion on how to improve this.?

thanks
kenny

i built one of these and it worked - the nitrates going in were about 20 (this was when i was having tank issues) and they came out as 0... The only problem was it could't process enough water to make a differance i have about 200 gallons of water and i used the highest rated eheim pump (not sure on gph rating) Denitrator was 2.5 feet tall had 75 feet of 1/4" coils and bioballs in the center chamber. The fastest i could get water through was a steady drip and it did not bring down my tanks nitrate at all. May have been beneficial on a smaller tank like 30 gallons or something.

its a very nice general description on how they work, and where to start in building one.

do they work YES, is that enough information to build you own, well its missing info, mostly size. you can search for one of a zilllion of these in the DIY, breeders forum and a few others and just copy it, or break down and do math.

1 75' run of 1/4" ID coils is right for about a 75 gal tank max

I would imagine these can become quite dangerous in the event of power failure or "reversed flow" due to siphoning or other mishaps?

Check valves? Bypass considerations?

Thoughts?

not really

well ok not realistically

as for power failures your tank will be in trouble before the denitrator, though its effectiveness will drop quickly it doesnt become "dangerous" for 4 or 5 days or more depending on volume of the bioball chamber. reverse flow wud be bad, but also not dangerous, it shouldnt be setup to return under water, it should always flow or drip from an elevated point into the water, this does a few things but first off it removes the temptation to not check up on it every now and then, it also adds o2 to the water fairly quickly the water will be trying to give off co2 and "suck" o2 in.

bypass well that depends on plumbing, check valves no they are not required and only add problems, pre filter things (whatever really) are a good thing though

How often or at all would you have to clean the bio balls?

never, once you seal the unit up, you cant open it, doing so would require the unit to recycle.

on a *LARGE* unit you would want a gunk drain for lack of a better word, but just a tap at the bottom you could remove large amounts of water over a very short period of time like 1 gallon as fast as you can but *LARGE*

Is this a safe bet for any tank? Or a last resort kinda thing if all else fails? Rotten egg smell will get me kicked out to live with the worms, spiders and other exiled creatures.

Bean

you wont get rotten egg smells unless you did something very wrong, at that point the denitrator has crashed it needs to be cleaned and re-cycled

as for what tank to put it on, its great for any FO, or FOWLR
reefs well it will remove nitrate, it wont help with phosphate, and doesnt do so great to that person with less than 3ppm ish nitrate trying to get to 0

Could this setup be gravity fed? I.E. from the tank to the sump or is it better pressure fed? I read about these in the past but have quite a renewed interest. Anything that I can do to lessen the scheduled water changes, the happier I am.

Bean

The water will never make it through the coils if gravity fed - you have to use a pump - and a good one at that... Actually the rotten egg smell is an indication that the denitrator is working properly, i dont remember exactly why it smells has to do with some biologicals in the water, What i did and i think everyone should do is run the efflent water through a small container with an airstone in it - this oxegenates the water and eliminates the egg smell.

umm ok well yes they can be gravity fed, and no the hydrogensulfate is a very much BAD thing it means that instead of consuming nitrate its consuming sulfur its also very bad for a fish tank, check out all the threads on hydrogensulfate in the chem forum, its the same problem with bad DSB's and plennums. it generally means you didnt follow the directions.

how are you going to get a gravity feed to run through 75 feet of presurized coils?

there is no requirement of "pressurized" and for a 75ft coil the rate is not much more than a very fast drip. you wanna process more water get more coils or a larger one.

Ied like to try one of these.... im debating between having one of these or an Algae turf scrubber... has anyone else built the denitrator one and had success?

S10

If the coil is at a level between the display and the sump... I would think the water will gravity feed through it. After all the output is lower than the input. In effect I siphon would be created.


I will simply drill a small hole slightly below the surface of the water and let it gravity feed the coil and drip the water into the sump. I could even drill the underside of the overflows horizontal plumbing.
Bean

these are not new. they are not new to this forum, there are a lot of people using them. if it were me id do both this and an ATS, though that pic looks big, they really are not. you can make one out of a 3" X 18" piece of pvc. thatll be good for a 75 gallon tank

a small U tube works great to get the water out of the tank, also you can put the coil below the tank itll still siphon up into the sump (assuming the sump is lower than the tank :D )

rsman, what is a happy size for a 125 gal tank :)

4" x 18" ?

i have one on my FO its a 125 thats heavily stocked with dirty fish its got one using 3 x 50' long .170 ID coils its 4" X 20"

Only 50' of tubing?

read carefully

.170 ID

this stuff is 1/4" OD its thinner, now that you know that, you can use shorter runs by using thinner coils. for a long time I had a small unit on my 7gal minibow it used 4 7' long coils using some very small vinyl tubing :D

Where do you pick up this magical thinner wall tubing? Its not the same as the icemaker tubing right? Iv never seen thin wall 1/4" tube.

hehe yea most icemaker tubing is 1/4" OD so is some of the drip irrigation stuff.

its not thinner wall its .170 instead of 1/4" because they measure the outside not the inside. its just where you buy and what its called some of its labeled .170 other is labeled 1/4" for the same stuff, if you go asking for 1/4" tubing you generally end up with 1/4 ID

i say it with emphisis because ive responded to a lot of coil denitrator threads and it gets lost to some.