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Re: Nitrates

Jim Seidman asked:
> What kind of plants and filtration do you have?

It's packed with mostly fast-growing plants. I have two
aquaclear filters running in each tank, and I'm using twice
the recommended filtration per gallon to ensure good
biological filtration.

> On the other hand, if you add CO2, some of that CO2 will react
> with water to form carbonic acid. (CO2 + H2O <--> H2CO3, meaning
> that CO2 and water turn into carbonic acid and vice versa.) So
> adding CO2 will lower your pH. But the more bicarbonate you add,
> the less effect on your pH adding the same amount of CO2 will have.

I was following you till that last sentence. I'm not quite sure
what that means. Are you saying that when there's more bicarbonate
in the water (higher kH), the CO2 is less effective in lowering
the pH (making carbonic acid)? Or are you referring to the fact
that pH is a logarithmic scale? Sorry, but I'm totally chemistry-

> In my experience, most people are talking about NO3 rather than > NO3-N.

I guess I got confused for a couple of reasons.
1) water chemistry professionals refer to nitrates as NO3-N, at
least that's what an EPA document I found on the web, and my local
water company does. We aquarists refer to nitrates as NO3.

2) Test kits by tetra use NO3 units but the result resolution is
pretty coarse. So, if I measured my 9ppm tapwater with one of
those kits, I'd get NO3 readings between 0-10 ppm.

> I live near Chicago and get my water out of Lake Michigan, so it comes > with about 1.5 ppm NO3. But just a few miles away are people on well > water with numbers that make your 8.8 ppm look low. Getting water with > 25 ppm NO3 is hardly unusual.

We get our city water from a reservoir. I guess all the runoff from
surrounding farmland raises the nitrate, but it's slightly offset by
rainwater. But the cumulative effect of nutrients would be larger
in well water. Thanks for the reassurance.

I appreciate the helpful comments. Thanks to you, Scott, and Chuck's
website, I'm less confused than yesterday.  :-)

cheers, shireen

Shireen Gonzaga Baltimore whimbrel at comcast_net