Hi,I have a 250l fresh water tank with an oscar and two plecos in it.Six months ago i've noticed i've got nitrate above 100ppm.So i bought another water test kit just to make sure the readings are good. Which they where. At that time I started frequent water changes which I saw a slight difference in the system, so I searched the internet and found this DIY Coil Denitrator which I build one.It is 2 feet long and 5 inch wide,has 75ft with 1/4 in diameter piping and at the center it is full of bio balls together with some valves at the top to regulate water coming in and out of the filter.It has been running all this time with a 60/90 drops/min and I did not see any results since than.Can someone suggest anything to solve this problem?

Hi, how often do you do your waterchanges and how much at a time?
Got no expierience with your project, but can't find anything out of the ordinary in your story.
What other filtration do you use?

I do water change every two weeks and I change about 20% of the water. I've got two cannister filters.

that may be a bit of a problem...
i do a 50% waterchange everyweek, and run a large sump.
It could be a bit too much bioload for your filters to handle.
But increasing your WC would probably not have been the purpose of you building your Coil...

Yes that was my intention.Not to increase wc.
Like you said my bio load can't cope with the system.
I have got one of the filters full of cyntered glass and ceramic rings.
The other one is devided into three.Filter floss.Activated Carbon.Ceramic rings.
Any suggestions?

add live plants? it would help.

It could be if you kept up with wc until you had a "acceptable"Nitrate-reading, that it would stay good.
But you got some big-time-mess-makers in your tank!
How many Gallons do your filters run per hour?

My two filters runs 1440 l/h which I think I have enough for a 250l tank.

How very true.
That should be more than sufficient, even without your coil.
When I ran my first tank nitrates orbitted off the scale and I had to do large wc's to get a normal reading.
I can't think of any other solution at the moment, than repeated WC and then test again.

can you describe you ritual during water change including
the filter maintenance? since you did not answer what
type is/are your filtering system, 1440l/h must be a canister
type, otherwise, it is under size....except for sump type

to be honest, increasing the media volume is more practical
in controlling nitrite and nitrate...more bacteria, more
efficient conversion of nitrite, then water change control
nitrate....

There is only one way to keep nitrates down to acceptable levels and thats water changes.

If you or anyone else finds a way to keep nitrates down without doing water changes tell us. You would be very very very popular

hey can i get pics of this thing??? im curious how it works. ive never heard of it.