Our member
@AbbeysDad had/has the same problem, high nitrate in his well water. He describes on his blog how he solved it. Here is the link to his blog:
And here is a link to the articles(I think I got them all).
I mean no disrespect to anyone, but in my view live plants will not help much. It is true that they assimilate ammonia/ammonium, and generally speaking they will take up all of it. Tom Barr told me that you really could never overload a tank with fish to the extent that a good growth of fast-growing plants would not be able to grab all the ammonia. Yes, some gets by to the nitrifying bacteria, but hopefully not much because this only results in more nitrate at the end of the process.
Plants do not want to convert to nitrate. it takes them about 24 hours to "switch gears" so to speak, and then they have to use valuable energy to change the nitrate back into ammonium in order to use it. Diana Walstad has this:
The ammonium preference of aquatic plants is substantial. For example, when Elodea nuttallii was placed in a mixture of equal parts ammonium and nitrates, the plant removed 75% of the ammonium within 16 hours while leaving the nitrates virtually untouched (Fig 1). Only when the ammonium was gone, did the plant begin to take up nitrates. Likewise, when the giant duckweed Spirodela oligorrhiza was grown in nutrient media containing a mixture of ammonium and nitrate, it took up ammonium rapidly, whereas it virtually ignored the nitrates (Fig 2). Because the plants for this particular study were grown under sterile conditions, the ammonium removal could not have been due to nitrification. Also, the investigator showed that plants grew rapidly during the study suggesting that N uptake was due to the plant’s actual use of this major nutrient. Nitrate uptake requires light energy. For example, Water Lettuce (Pistia stratiotes) took up nitrates in the dark at 1/3 the rate than it did in the light. In contrast, light had no effect on ammonium uptake; plants took up ammonium at the same rate with or without light [4]. Nitrate uptake does not occur until plants are forced to use it, that is, when all ammonium is gone. Even then, there is a delay, because the setup for nitrate uptake must be generated first. Thus, Water Lettuce required 24 hours to attain its maximum rate of nitrate uptake [4].
Another stumbling block is the balance issue. If ammonia/ammonium should become depleted, in balance with the other 16 nutrients and the light intensity, only then will plants waste the energy on nitrate. In most of our natural or low-tech planted tanks, we have a good stocking of fish (most of us anyway) and the light and nutrients are unlikely to be sufficient to jump ahead of the nitrogen.
Nitrate at 30 ppm is a lot. And in my view the normal plant load cannot take this up to any appreciable degree. Even in high tech planted systems the nitrate assimilation by plants is so far as I have ever been informed much less than this. Massive water changes are done to dilute all this. These work because the nitrate is not coming in with the water, this is a very different issue.
