Low range NO3 testing

[Scoot]

I posted about this a long time ago. Can't find a local suppier of hi-res NO3 test kits, so I'm wondering if anyone has oversampled or half-sampled the Aquarium Pharmacueticals Nitrate test? If you double the water source to 10ml, or cut it to 2.5ml, is it possible to get an accurate reading of 1/2 the scale of the card? So 10 on the card means 5, 5 on the card means 2.5, etc.

I did this successfully while cycling, with the ammonia test, cutting the sample in half to read very very high ammonia levels (in the 80's at one point I think).

I'm steady under 5ppm of NO3 now, and would like to see day to day changes (and the effect my various maintainance efforts are having) more accurately than "a little under 5", "a bit over 0", etc., as I try to reach the "mythical" (heh) number of 0ppm NO3.

 

[melosu58]

I just think you need not worry about it. IMO if you are under 10 you will be OK. If you can get it to 0 well that is fine but I dont believe you`ll have any problems under 10. IMO also I believe the best way to get that last 5 or 10 PPM you will need some type of nutrient exporting like Macro algeas or mangroves or the like. But of course this is just an opinion I share

 

[roka64]

I guess you are looking for a more precise test kit, right? You might look into digital testing equipment. From what I have seen (a little bit) they tend to get down to the more nitty gritty, lower numbers and are pretty expensive.

 

[tecwzrd]

As melosu58 said even for reef tanks 10 ppm no3 or less is fine. Most of us never keep it at 0 for very long and I do 20 gal changes a week (55 gal tank) to keep mine around 5 ppm.

I have used half as much water in the tube with the same 10 drops of each bottle to get "double" results but only do it if I'm unsure if the reading is 0 or 5 ppm since it's hard to tell.

Salifert no3 tests are no better trying to decipher low range IMO.

 

[rubikcube]

I like the SeaChem kit that I have. My nitrates usually measure around 1 on their test. Another thing I like is that there is a very significant color difference from 0 to 1 and from 1 to 2.