Richard Sexton wrote:
I can't get NO3 to lower than about 8ppm on a very good day. I've never
added N directly to any of my tanks. On the other hand, PO4 seems to be
sucked away as if there's no tomorrow. I have to add PO4 every few days.
I'm not sure what's going on with K, but I do add K2O, haphazardly. I
need something to initially gauge what's going on with it so that I can
create a dosing regime.


Sounds like it could be nitrate leeching from your gravel. Two big water
chnages will get rid of most of that. I aim for 20-30ppm NO3 so I'd
still ad kno3 in your case.

Well, I began to think it was my NO3 test kit, but a different make of
test kit gives a similar reading. My tap water has 25ppm of NO3. RO
water still has half that amount. I think I'm going to check the test
kits against rain water to calibrate them if possible.

Just had an idea. I'll check against my dehumidifier water.

Nikki