George Monnat Jr Posted February 28, 2013 Author Share Posted February 28, 2013 Or been a bad batch. Quote Link to comment Share on other sites More sharing options...
victoly Posted February 28, 2013 Share Posted February 28, 2013 Ive had pretty good experience with hanna customer service, I'd write them, tell them whats up and get them to send you a new unit with new reagent. Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted February 28, 2013 Author Share Posted February 28, 2013 Yea, I tried that (see first part of this thread). Quote Link to comment Share on other sites More sharing options...
victoly Posted February 28, 2013 Share Posted February 28, 2013 I hear ya. still, they're in it to keep you as a customer, and if you point them to this thread, they might send you out another unit. Sounds like a hardware or reagent issue. I've tested mine against some pretty sophisticated lab equipment, and have had satisfactory results. Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted March 24, 2013 Author Share Posted March 24, 2013 For the past week or so I've been using the Hanna Checker HI 713 to track my phosphates. I've been running a constant 1 cup of BRS Bulk Granular Ferric Oxide (GFO) – High Capacity (recommended amount) being gently tumbled in a BRS GFO & Carbon Reactor – Dual (w/ GAC, too) for weeks. victoly got 0.15 ppm PO4 on the 16th. Here are the subsequent readings: March 19th: 0.21 ppm, 0.12 ppm and 0.21 ppm PO4 (3x packets used); RCA tested from the same water and read 0 ppm detectable PO4 March 20th: 0.50 ppm, 0.04 ppm and 0.06 ppm PO4 (3x packets used) March 23rd at 1150 AM: 0,03 ppm PO4 - great! Then at 2310 (11:10 PM) that night, I read it again for 0.11 ppm. What? I decided to do four tests using the same pair of cuvettes/bottles. I wiped each bottle before inserting it each time. Here are the four more readings I got on the same samples (only 1 packet used for all readings): 0.11 ppm 0.02 ppm 0.46 ppm 0.06 ppm 0.07 ppm What should I do with that? Throw out the high and low outliers and average the remaining? I don't know what to think. RCA always reads 0 ppm, my HC reads sporadically and I still have GHA and small patches of occasional dino. Quote Link to comment Share on other sites More sharing options...
(Bio)³ Posted March 24, 2013 Share Posted March 24, 2013 any scratches on cuvets or micro bubbles in the vials ever? I'd eliminate the one obvious out of whack test and average the rest. 1 Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted March 24, 2013 Author Share Posted March 24, 2013 any scratches on cuvets or micro bubbles in the vials ever? I'd eliminate the one obvious out of whack test and average the rest. Not that I can see, I used a soft cloth to clean the bottles each time. 1 Quote Link to comment Share on other sites More sharing options...
victoly Posted March 24, 2013 Share Posted March 24, 2013 My personal belief is that the occasional whacky answers are the result of a bubble or undissolved reagent sitting right in the light path of the LED/photometer. I try to combat these by a) doing the dual cuvette method so that I'm very sure that the reagent is fully dissolved (and I don't go into a rampage when the thing powers down) and b)use the bubble head space on the upper portion of the cuvette to "wipe" any bubbles on the inner glass surface before i set the push button timer. I also try to handle the bottles by the lid or bottom (anywhere out of the LED path), and wipe the bottle with a lint free cloth prior to the clean water zeroing and also to the cuvette that you're going to read out of. 1 Quote Link to comment Share on other sites More sharing options...
(Bio)³ Posted March 25, 2013 Share Posted March 25, 2013 I used to flick the cuvets like a syringe to dislodge any little bubbles, by doing this and methods similar to what ian said above I've gotten more accurate readings. 1 Quote Link to comment Share on other sites More sharing options...
+Capt. Obvious Posted March 25, 2013 Share Posted March 25, 2013 Also, swirling (not shaking) plus flicking once dissolved has gotten me very reliable results as well Quote Link to comment Share on other sites More sharing options...
+Capt. Obvious Posted March 25, 2013 Share Posted March 25, 2013 Also, make sure you don't touch the inside of the reagent envelope when opening, as it can effect the results Quote Link to comment Share on other sites More sharing options...
victoly Posted March 25, 2013 Share Posted March 25, 2013 Nitrile gloves baby! 2 Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted March 25, 2013 Author Share Posted March 25, 2013 The HC for alkalinity works like a charm. I've been double-checking with my remaining Red Sea, and they've tracked beautifully. And I need to pull out my gloves for the PO4 HC. I need to refresh my med go-kit anyway. A question for both of these. I'm assuming that the 10ml is measured at the bottom of the meniscus on the line, is that right? Quote Link to comment Share on other sites More sharing options...
(Bio)³ Posted March 25, 2013 Share Posted March 25, 2013 I always measure based on the bottom of the meniscus 1 Quote Link to comment Share on other sites More sharing options...
victoly Posted March 25, 2013 Share Posted March 25, 2013 SOP for labs is to measure where the bottom (middle) of the meniscus hits the top of the measuring line. 2 Quote Link to comment Share on other sites More sharing options...
victoly Posted March 25, 2013 Share Posted March 25, 2013 The HC for alkalinity works like a charm. I've been double-checking with my remaining Red Sea, and they've tracked beautifully. And I need to pull out my gloves for the PO4 HC. I need to refresh my med go-kit anyway. A question for both of these. I'm assuming that the 10ml is measured at the bottom of the meniscus on the line, is that right? Do they track after a correction or straight off the meter? Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted March 25, 2013 Author Share Posted March 25, 2013 The last two examples as HC, Red Sea dKH 5.208, 5.1 7.560, 7.7 That's pretty good given that the Red Sea color change can be subtle and hard to see. For the HC conversion from ppm to dKH, I used: dKH = ppm / 50 * 2.8 Quote Link to comment Share on other sites More sharing options...
+Jakedoza Posted March 25, 2013 Share Posted March 25, 2013 Sounds like someone needs a refugium... Quote Link to comment Share on other sites More sharing options...
victoly Posted March 25, 2013 Share Posted March 25, 2013 Not sure if serious.....Thats alk and not phosphate.George, great to hear that it is tracking straight up with the red sea. There was some scuttlebut that the HC alk consistently read too high by something like 18%. Good to hear you're seeing otherwise. Quote Link to comment Share on other sites More sharing options...
George Monnat Jr Posted March 25, 2013 Author Share Posted March 25, 2013 I had a snowstorm that dropped my alk from 8 to 5 due to keeping my pH above 8.4 fighting dino. It's a bad idea to add kalkwasser and baked baking soda within 20 minutes of each other, Another lesson learned. But I've recovered and built it back up to 8.5 dKH with all parameters back to good. I have a reverse lit refugium with chaeto and thriving amphipod and brittle star communities. Quote Link to comment Share on other sites More sharing options...
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