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[APD] Re: low-range pH test kit recommendation needed

Message: 13
Date: Tue, 23 Sep 2003 11:09:28 -0400
From: Shireen Gonzaga <whimbrel at comcast_net>
Subject: [APD] low-range pH test kit recommendation needed
To: aquatic-plants at actwin_com

Hi ... can someone recommend a low-range pH test kit, one
with 0.1-0.2 increments with clear color charts? I have the
Hagen test kit that has 0.2 increments but I have trouble
distinguishing the colors below 7.0. The Tetra kit has 0.4
increments which is too large. I tried to find the LaMotte
narrow range kit on their website but all they have listed
for freshwater is 5.0, 6.0, 6.5, 7.0, 7.5, 8.0, 9.0, 10.0
(http://www.lamotte.com/pages/aqua/testkits.html)

Shireen,

Forget the test kits and get a good pH pen. They are relatively inexpensive, these days, and don't need constant reagent replacement. They read from 0 to 14, with good resolution everywhere but the extreme ends.

You *will* need a pair or three of test buffers to periodically check and reset the calibration. pH pens are much more subject to drift than tds or conductivity meters. Nevertheless, they are more accurate and cheaper (long-haul) than LFS test kits, usually.

If you get pH buffers at 7 and 4, you can double-duty the 4 and use it as a soak to remove any buildup on the probe that can make it unreliable and cause it to drift. My pens seem to last forever, that way (at least until I drop them in the tank!). I like a 10 buffer as a linearity check, so I can roughly predict any slight errors between 4 and 10.

Wright

--
Wright Huntley -- 760 872-3995 -- Rt. 001 Box K36, Bishop CA 93514

           Mencken's maxim—every election is a sort
             of advanced auction of stolen goods.



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