Dragos,
La prima vedere este complicat intr-adevar, cel putin fata de procedura indicata de Hanna. Cu toate acestea acuratetea celei prezentate mai sus este mult mai mare deoarece dilutia in serie este mult mai precisa decat dozarea unei cantitati de 0.1ml apa de acvariu (asa cum indica Hanna) si implicit induce o eroare mult mai mica (intre 2-5% fata de procedura Hanna 10-15%).
Apa deionizata este produsa tot de Hanna Instruments si o poti comanda de unde ai luat si minicolorimetrul.
Codul ei este HI 70436 si vine intr-un bidon de un galon (aproximativ 3.8 litri) suficient zic eu pentru destule testari.
Hanna Instruments o recomanda in locul apei osmozate. Poti incerca cu apa purificata de la farmacie dar nu stiu ce procedeu este folosit pentru a o purifica.
Uite si cateva FAQ ale Hanna Instruments pentru acest minicolorimetru (nu mai stau sa le traduc

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Q: Is using deionized (DI) water really necessary? Is reverse osmosis (RO) water good enough?
A: It is necessary to use DI water. Any calcium remaining in the RO water will get magnified during the test results, and will give a false high reading. DI water is available for purchase at many pharmacies, or it can be ordered from Hanna, HI 70436 (500 mL). Distilled water is also acceptable, depending on the source.
Q: The HI 758 is reading higher than expected, or is flashing 600.
A: Be sure that the distilled or DI water is used in step one of the instructions. Purchased distilled or DI water sometimes has electrolytes added back in. These electrolytes are usually forms of calcium and magnesium. This will cause a false high reading during this test.
Q: The test really only uses 0.1 mL of tank water?
A: Yes. Add 1 mL of Reagent A and 9 mL of DI (or distilled) water to the cuvette to fill it to the 10 mL mark. Press “C.1” to zero. Add 0.1 mL of tank water and one packet of Reagent B to the same cuvette. Gently invert for a few seconds to mix, let it rest for a few seconds, then insert in the meters and press “C.2” to read.
Q: The meter is reading solid 200, instead of flashing 200, when the reading is too low.
A: This is a misprint in the manual. The meter will normally display 200 when the reading is 200 or lower.
Q: Is it necessary to use the color-coded syringes as indicated?
A: Yes. Use the white syringe ONLY with Reagent A. Use the green syringe ONLY with sample water.
Q: Is it necessary to use the tips with the syringes?
A: Yes. They are necessary to dose the precise amount of reagent or sample.
Q: What’s the best way to use the syringes with tips?
A: With the tip firmly on the syringe, insert the tip opening fully into the reagent or sample. Pull the plunger back until the bottom of the plunger is even with 1 mL mark. This applies both to reagent and sample.
Q: There is air inside the syringe IS THIS NORMAL?
A: Yes it is normal. Using the tip ensures that the correct amount will be dosed, regardless. Push the plunger in until the bottom is level with 0.9 mL (for sample) or 0.0 mL (for reagent)
Q: There is reagent or sample left in the tip IS THIS NORMAL?
A: Yes this is normal. Using the tip ensures that the correct amount will be dosed, regardless.
O zi buna
Gabriel