taekwondodo Posted May 8, 2005 Share Posted May 8, 2005 I am using the Lamotte Ca Test kit. 1ml of tank water, fill remaining to 12.9 ml w/ RO water (tested, Ca=0 in the RO water)... 6 Drops of the NaHO2, stir, add calcium tablet, stirr more. Titrates at 200+180 = 380 Multiply by 12.9 = 4092 ppm CaCO3 Convert CaCO3 to CaCL multiply by 1.11 = 5441.2 ppm CaCL To convert CaC03 to Ca, multiply CaCO3 by 0.4: 4092* 0.4 = 1636.8 ppm Ca :blink: my estimate is that it should be 1/3 of that (~550ppm). I am using Oceanic, sg = 1.021. I've done this test three times, with both old and new reagents. What's the problem? Thanks, - Jeff Link to comment
Kogut Posted May 8, 2005 Share Posted May 8, 2005 Calculations have to be wrong... A level of 1636 is impossible. Link to comment
taekwondodo Posted May 8, 2005 Author Share Posted May 8, 2005 I know that - but I've done the test three times with two different sets of reagents!!! Do you use Lamotte? Am I missing something? Thanks, - Jeff Link to comment
randygsx Posted May 13, 2005 Share Posted May 13, 2005 How are you getting those calculations? Did they come with the kit? ~randy Link to comment
taekwondodo Posted May 14, 2005 Author Share Posted May 14, 2005 They did. Follow-up: Contacted LaMotte - seems these reagents were made in 2001 (doh!) and are wayyyyyy out of date (even though I just got them a year ago and just now opened them for the first time). Link to comment
lgreen Posted May 14, 2005 Share Posted May 14, 2005 are you sure you just didn't miss a decimal point somewhere? 409.2 wouldn't be too bad Link to comment
lgreen Posted May 14, 2005 Share Posted May 14, 2005 also titrated at 380 what? ml, drops, what? Link to comment
taekwondodo Posted May 14, 2005 Author Share Posted May 14, 2005 the lamotte kit has a reading indicator on the titration syringe. Used it many times for FW and never a problem (when looking for Ca valuse in the 50-60s).... Take the titration indicator value and multiply by 10. Link to comment
lgreen Posted May 14, 2005 Share Posted May 14, 2005 sorry, maybe i missed something, but why do you multiply it by 10? that is what I am saying, because if you don't multiply by 10, you get 409.2 which actually makes sense. Link to comment
bobioden Posted May 14, 2005 Share Posted May 14, 2005 That kit sounds really confusing. Multiply, convert... And I thought the Salifert CA kit was confusing at first. Bob Link to comment
lgreen Posted May 14, 2005 Share Posted May 14, 2005 typically in a freshwater environment perhapds you would find a lower Ca2+ reading, so that is why I am thinking they have you multiply by 10 to get a low range reading. Perhaps not multiplying by 10 would get you back into normal/high range. i dont know. we used those lamonte kits in HS and i thought they suck. too complicated Personally i would just get a salifert Ca2+ test kit. Link to comment
inkto Posted May 14, 2005 Share Posted May 14, 2005 those directions are nowhere near what my lamotte ca test indicates. I simply take the value from the syringe after titration and multipy by 5.16. I purchased it a couple months ago. ie. I typically titrate to 80 which gives me 412.8 = (80*5.16) Link to comment
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