Nitrate

[Erns]

What is your ideas on 'safe' levels for nitrates? What test protokol do you follow? drops, tabs, poweders or digital? Accuracy?

I use the Hanna C203. My current levels are around 15- 25ppm. When using the tablet test I get a way different reading. Any similar experiences out there?

[MikeM]

Nitrate is relatively harmless. However, for the best development, the lower the better. Nitrate contributes to yellowing of shiroji, reduces lustre, prematurely ages the skin and does nothing good. It simply is not life threatening like nitrite.

In my old pond I often had nitrate levels at 25ppm or higher. After trees in the vicinity were removed by hurricanes in 2004, nitrate levels dropped considerably. In my current pond nitrate is typically well under 10ppm, and usually at or below 5ppm.

[Erns]

Quote: Originally Posted by MikeM Nitrate is relatively harmless. However, for the best development, the lower the better. Nitrate contributes to yellowing of shiroji, reduces lustre, prematurely ages the skin and does nothing good. It simply is not life threatening like nitrite. In my old pond I often had nitrate levels at 25ppm or higher. After trees in the vicinity were removed by hurricanes in 2004, nitrate levels dropped considerably. In my current pond nitrate is typically well under 10ppm, and usually at or below 5ppm.

Mike
do you have a shower type filter in your system?

[JasPR]

5 ppm or below. This is not because of toxicity. But because nitrate is an indicator of polluted water. Water that shows a high nitrate needs to be changed ( diluted and restored) as nitrate is only the 'tip of the pollution iceberg'. So if your alkalinity is slipping and your nitrate is growing, you need to intervene more often! at 30 ppm nitrate your koi are likely to also be seeing more bacteria, more prganic and lower ORP. it's all related. One of the most frustrating things is trying to get newbies to understand that forcing one or two parameters to 'read' well is not the same thing as a well run pond. Using Ozone or PP to make ORP meters to 'read well' or adding baking soda to make an alkalinity test 'read well', or to keep pH from crashing is just not the same thing as a pond that can hold these things naturally ( until a water change restores and dilutes).
So can you say that nitrate is toxic to fish in the higher levels we see regularly? No you can't. But can you say that high nitrate goes hand in hand with an environment that is trending towards unhealthy for koi ?- absolutely you can. Above 5 ppm its time to be thinking -- water change. JR

[MikeM]

Erns: Yes, there is a Bakki Shower on the pond.

I have received comments that heavy aeration, use of a "shower filter" and the like does not remove nitrogen from the system through degassing, etc. Rather, it is said, nitrification rates increase so ambient levels of ammonia and nitrite become even lower, but nitrate levels will max at the same level by the time of the next water change. I have also read that ammonia will degas. My personal experience has been that nitrate levels were immediately lower using multiple heavy aeration/degassing techniques. I keep meaning to search out reliable science literature on the subject, but never seem to get around to it.

[KoiCop]

MikeM . . .

I'm not sure you'll find that reliable scientific literature.

I well remember vsound's cogent arguments on another board that while a small amount of ammonia will volatize, nitrite and nitrate will not. And that while it's 'cycle interruptus' for that small amount of ammonia (i.e., no nitrite or nitrate will be produced from it, since it has left the system), volatization cannot account for the substantially lower nitrate levels that you and others with TT's and bakis have observed.

And no one was able to successfully debunk his scientific arguments.

Maybe since then JR's come across . . .

[JasPR]

No , no new science. Just more observation. And this is one of the very few subjects I find I agree with Roddy on?!! Use of TTs reduces the nitrate reading. I know what vsound said and it is fact so it is hard to argue. But it may not be as simplistic as a single measurement. You know my rap on this--

A TT driven pond makes for a 'leaky' system. That is, you create a second water surface/atmosphere interface by running thin layers of water over a gigantic surface. All of the sudden, a 20 X 10 pond surface becomes a 60 X 30 pond surface!
Add to this another fact- koi ponds are progressively organic environments. Ammonia is produced by fish ( gills and dilute urine) and it is produced from organic decay ( it is also an oxygen killer). The contributors here are biological byproduct like slime and feces, Algae death, organics from the surface and accumulation of related amino acids on the water surface and on media in the towers.
The nitrification process is also not as neat a process as we imagine in such systems. We have other species competing for nutrient and organics complicate the competition. So you have ammonia and many other nitrogen species including gases. All of this, will be in measurable ammonia in the end, in a system service by a submerged biofilter .

The theory therefore, as to why so many hobbyists note a drop in nitrate after using TTs ( this has been observed by scores of advanced hobbyists in serval countries), is that you leak the stages of ammonia creation and conversion so that the net result ( nitrate) shows the cumulative effect ( lower reading) of many tiny 'leaks' of nitrogen species along the way. That's my theory and I'm sticking with it until someone can show me a better explanation for the phenomena. - JR

[KoiCop]

JR . . .

Sounds good to me.

Now all we have to do is figure out an experiment to qualify and quantify 'nitrogen leaks' -- and then prove that they account for the missing nitrate.

[JasPR]

yep. I like to reverse test these things just to gain perspective, and it is a good way to test out the kits you use. If you have a two circuit system ( a submerged and a TT or bakki) if you take the TT off line for a week or so, you can watch you nitrite rise to some higher ambient level between water changes. Put your TT/bakki back on and watch the nitrate reading drop over two-three weeks. JR

[Eugeneg]

Quote: Originally Posted by Erns What is your ideas on 'safe' levels for nitrates? What test protokol do you follow? drops, tabs, poweders or digital? Accuracy? I use the Hanna C203. My current levels are around 15- 25ppm. When using the tablet test I get a way different reading. Any similar experiences out there?

I read in Rinko about a Japanese koi keeper that had the water from his pond go through a canal and there he grew tomatoes . I made a 2ft deep x 2ft wide and 20ft long channel which is fed from my skimmer and filled with bare root grasses . I took one test about 10 years ago and never bothered since .
It works for nitrate removal and works better than any difractunator
Regards
Eugene