Randy Holmes-Farley
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Does the manual say that means less than what?
Exact iDip Digital Water Testing
- Thread starter Rockinreefs
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Does the manual say that means less than what?
Greenstreet.1
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They say range is from 0.02-5ppm.
This is the range chart.
This is the range chart.
Greenstreet.1
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They say it represents the best possible accuracy under laboratory conditions. It's in the fine print at the bottom
Greenstreet.1
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It's on point with salifert when it comes to alk and cal I'm happy about that. Will do po4 again after water change in a few almost forget Hanna was 0.00 po4 will test with both of the in a few.
Randy Holmes-Farley
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I would interpret this as a +/- percent value near the higher end of the range, not at the low end.
For example for phosphate, at 5 ppm it might be 4 ppm +/- (8% of 4 ppm) = 4.00 +/- 0.32 ppm
but that wouldn't be true at the lower end, say 0.03 ppm, which likely is not 0.0300 +/- 0.0024 ppm.
For example for phosphate, at 5 ppm it might be 4 ppm +/- (8% of 4 ppm) = 4.00 +/- 0.32 ppm
but that wouldn't be true at the lower end, say 0.03 ppm, which likely is not 0.0300 +/- 0.0024 ppm.
SPotter
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That would seem to be a much narrower margin of error than many of the other kits out there correct?
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Not sure.
If we look at alkalinity, one might get a reading of 11 +/- 0.8 dKH, or 8 +/- 0.6 dKH. That does not seem better to me than a good titration kit using a syringe, but I've not seen stated error bars for most kits.
Greenstreet.1
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Just got of the phone with them I waiting on an email about getting the mag results.
SPotter
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I would really be interested in it for alk and nitrate testing. I have the Milwaukee Martini Low Range Photometer and that has been rock solid since buying it two year ago. For alk I have used the Hanna checker and LaMotte test kit and I have noticed that when I open a new bottle of reagent the numbers are very close but as I use more of the Hanna bottle my alk declines and LaMotte stays stable. Like right now I am 3 weeks into using a new a bottle and I am getting readings on Hanna of 105-107 and my LaMotte kit is showing 140 but I often question my color decoding abilities and would like a more reliable way of testing. I test alk and po4 a few times a week, nitrate once a week and the rest 1-2 a month so I am trying to figure out if this new toy is really going to be worth it for me.
Randy Holmes-Farley
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Curious that you see that drop over time.
Hanna doesn't say much about it, but I expect the way the Hanna works is to add a fixed amount of acid and see where the pH needs up, giving an indication of the alkalinity. How that is impacted by the reagents being used over a month is hard to say. Maybe their pH-indicating dyes are not fully stable against air oxidation.
SPotter
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this might be worth the investment just for alk and nitrate if the numbers are consistent and hold up especially since my eyes aren't what they used to since I am getting older...lol. I hate trying to distinguish color comparisons on the chart.
Greenstreet.1
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So far the alk has been on point for me just a little lower than salifert. Spoke to them about the mag they sent me new directions need to order a sulfate test then I will be able to get the mag results.
Randy Holmes-Farley
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Why would you need a sulfate test?
Greenstreet.1
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I will post what they sent me hold on
Randy Holmes-Farley
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That doesn't make sense, unless it is a software thing where you must have a value.
Magnesium in this method is total hardness minus the calcium hardness, and then converted to the right units.
It doesn't use any of sulfate, alkalinity, or chloride.
Try randomly changing those sulfate, chloride or alkalinity values in the calculation (if you can) and see if they have any effect. Even 0 ppm should be unimportant.
Magnesium in this method is total hardness minus the calcium hardness, and then converted to the right units.
It doesn't use any of sulfate, alkalinity, or chloride.
Try randomly changing those sulfate, chloride or alkalinity values in the calculation (if you can) and see if they have any effect. Even 0 ppm should be unimportant.
