I've been thinking about getting one of these but I'm having problems seeing if it's truly any good. I'm hoping someone can prove my math wrong.
say you get a reading of 170ppm w/ the checker. (170/50)*2.8 = 9.52 dkh which seems really nice and precise and accurate.
NOW... the accuracy of the Hanna checker has an accuracy of 4% so what that really means is the ALK value is somewhere between +/- 4% of 9.52 which is 9.1 and 9.90.... that is really no better than an API test kit.
From the details it states "Accuracy 4% ±0.04 ppm (mg/L) of reading 0.04 ppm (mg/L)" please someone tell me I'm not understanding this properly. Cheers.
Never mind the math! The advantage is that its easier than using a test kit.
9.1dkh, 9.9dkh, Both are acceptable alk values.
I would argue that if that's the accuracy i'm getting it's not that much easier than the API titration kit.
I use the Hanna Phosphate one b/c i can't test to that level with a kit, but I don't believe this is worth an extra $30 plus only 30 tests compared to an API kit.
Common how hard is (fill with 5ml) drop drop drop drop drop drop drop drop -shake- drop done...
Plus if/when you're running a ULNS system the difference between 9 and 9.9 dkh is quite a bit.
There has got to be a reason they are so cheap? Does anyone have one that can share their experience? The + or - 4% is fine for most tests I figure. I mean test kits may be similar accuracy but that is if they are working properly, there is no human error, and if you have a super human eye for differentiating colour :)
Quote from: lost_at_sea on March 22, 2011, 05:04:44 PM
I would argue that if that's the accuracy i'm getting it's not that much easier than the API titration kit.
I use the Hanna Phosphate one b/c i can't test to that level with a kit, but I don't believe this is worth an extra $30 plus only 30 tests compared to an API kit.
Common how hard is (fill with 5ml) drop drop drop drop drop drop drop drop -shake- drop done...
Plus if/when you're running a ULNS system the difference between 9 and 9.9 dkh is quite a bit.
If you're happy with the API kit then I wouldn't change to the Hanna because you may not get the value out of it. I have been using the API Alk kit for 2 years now and I hate it. I have a hard time judging the colour for some reason and therefore have never trusted the results.
When I tested with the Hanna for the first time it came in at 7.65ppm whereas the API required 9 drops to effectively change colour.
I do very much like the fact that you only need to purchase one kit (for years), I dislike the waste that goes along with some of the other kits. I have a plethora of old syringes, plastic vials, bottles etc.. from my other kits but again that's a personal preference. The individual API kits are actually better for that in that you only have to buy the one bottle. My Seachem Calc. kit on the other hand became useless when the powder got damp and the whole thing had to be tossed. Plastic box, foam, syringes, bottles etc.., it's a waste. I had only used it a dozen times.
Every kit has a margin of error so consistent results are really more important than exact results when measuring ALK.
Quote from: FocusFin on March 22, 2011, 06:10:40 PM
I do very much like the fact that you only need to purchase one kit (for years), I dislike the waste that goes along with some of the other kits. I have a plethora of old syringes, plastic vials, bottles etc.. from my other kits but again that's a personal preference. The individual API kits are actually better for that in that you only have to buy the one bottle. My Seachem Calc. kit on the other hand became useless when the powder got damp and the whole thing had to be tossed. Plastic box, foam, syringes, bottles etc.., it's a waste. I had only used it a dozen times.
Very good points regarding waste! Also you probably would save money in the long run as the reagent is fairly cheap.
Also after doing some digging a MUCH easier formula for converting ppm > dKH
ppm x 0.056 = dKH
We have done some testing before bringing them in and the reading from a Salifert test and the Hanna checker were the same. One thing they say tho, you need to dry the cuvette before putting it in the checker because that might give you bad readings :)
Quote from: lost_at_sea on March 23, 2011, 06:36:24 PM
Also after doing some digging a MUCH easier formula for converting ppm > dKH
ppm x 0.056 = dKH
yup that is the formula that comes in the instructions for the checker.