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#1
03-12-2009, 02:10 PM
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I remember when I used to be a vodka reactor...
I was going to take my tub back to OA and get some seachem.. But I love to see this kind of customer support so I will stick with the h2o and give it a shot... Plus that article from aquarium water testers takes a little luster off of the seachem reef.... I'm with gsp on staying with tropic marin pro if anybody was going to keep carrying it. 
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#2
03-12-2009, 04:50 PM
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Quote:
To add to what I said earlier I saw that a couple of people had readings that were outside the range that we publish and this concerns me about the method of testing. We are extremely confident about the levels that we achieve - so much so that we print both a standard and a range on each bucket - how many companies give you that much information in the salt market?. There are retained samples of each 1 tonne batch (batch number on the instructions) and in the past we have had queries about measured levels and gone back to the samples and fond the salt to be correct. From this I have produced a series of FAQ's on our website to allow people to fully understand our experience with testing and how people use the testing equipment. http://www.theaquariumsolution.com/node/576 http://www.theaquariumsolution.com/node/494 An extraction from the above is as follows Whilst we are checking the parameters again I would like you to recheck your own tests and hopefully learn a few things from the further information below. SALINITY The levels on the salt are given at a salinity of 1.025 at 25C or 35.5ppt To measure this salinity with a refractometer you must aim for a reading of 1.0262 as a refractometer will always measure as if the water is at 20C. (most refractometers have on the viewer 20/20) If you read our salt instructions you will see how to calibrate the refractometer properly which say that the instrument must be at 20C during calibration and not the water. When you then take a reading the REFRACTOMETER will always measure the SG as if the water is at 20C as the small amount of water that you add to the slide will have no impact on the temperature of the equipment and will soon change to the same temperature as the refractometer. What ATC ( auto temperature compensation) means is that once calibrated at 20C you can use the refractometer in higher ambient temperatures where the instrument is hotter or colder. If you use a HYDROMETER which is calibrated at 25 then you must have the water at 25C to get a reading of 1.025 at 25C, (check the calibration temperature printed on the hydrometer). If the water is colder than 25C then you can use the chart on the salt instructions to work out what the salinity must be at that lower temperature so that when you warm it to 25 it drops to 1.025. Complicated stuff but simple when you understand it. Whilst writing this reply I have realised that the temperature chart has a mistake on it. It should say on the right hand column "hydrometer calibrated at 25C" and not "SG calibrated at 20C". I changed this as the most common measuring tool was a refractometer however as I have already explained - a refractometer will always read as if the water is 20C and so you always must aim for 1.0262 if you want 1.025 at 25C. TESTING What we also found during development was how difficult it was to get accurate testing and we tried a lot of hobby kits against water samples measured in the laboratory. We even sent the same water off to a number of laboratories as 2 separate blind samples and got different results on some parameters, (not on magnesium), on the same water, so if laboratories find it hard to measure then what chance have we with hobby test kits. What we did conclude is that the Tropic Marine Calcium/Magnesium Test Kit was the most reliable and accurate of the kits that we tried and agreed with the laboratory for magnesium every time. This is not the easiest kit to use and obtains a magnesium reading having first measured the calcium level. You therefore get 2 results with one test kit. Other test kits we found could often be variable and sometimes out by up to 10% either way, although we did not test all manufacturers' kits. If you follow the above many people will find that their salinity or SG is not as high as they think it is which is why the readings are often lower than we publish. Hope this also helps a few people Cheers Stuart
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#3
03-12-2009, 06:52 PM
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Thanks Stuart!
I was going to stick with H2O (as I mentioned earlier) because I have had nothing but great results with it and it tests within range each time I test but this just reassures me even more I guess. Nice to have you come here and explain things. And put this whole thing to rest. I think your explanation was pretty much exactly what a few of us thought...salt is only manufactured in a few places around the world so many different mixes are made at the same place but that doesn't make them the same product...
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