Jim,

Sounds like my "guesstimate" was off, but still... When I calculate the
TDS of the 12-6-13-7Ca-2 Mg stuff I've got, one teaspoon per gallon gives a
calculated nitrogen loading of 156 ppm and a TDS of 454 ppm, so if I lowered
the N to 125. the TDS would be 364, not 700.

The "Orchids" analysis - adjusted to 125 ppm N - gives a calculated TDS of
357 ppm.

FWIW, when I calculate the TDS of my nutrient solution using RO @ 10ppm
TDS, Dyna-Grow and Pro-Tekt, it comes out pretty close to the values I get
on both of my TDS meters....

I have to wonder what the disconnect is between our values.
--

Ray Barkalow First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!


"James Aldridge" wrote in message
...
Ray,

The 125 ppm N for my 13-3-15 + Ca/Mg RO fertilizer gives an EC of
about 1000 uS/cm or a TDS of about 700 ppm. Do you still think this is
ok for routine use (not with paphs/phrags etc.)?

Jim

On Fri, 20 Jun 2003 15:50:56 -0400, "Ray @ First Rays Orchids"
wrote:

Hey, Jim.

Why halving the dose? I'm a believer in constant-but-low rate feeding,
but
125 ppm N seems pretty low already - using the formula in "Orchids," the
N+P+K gives a TDS of about 258 ppm for 125 ppm N, or a guesstimated total
of
around 300-325, including the other stuff.

James Aldridge, Fort Worth, Texas, USA
- www.JamesAldridge.us
- www.FWCDS.org