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Pod Your Reef

Best Alk Test?


Bill Nye

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I am in the market for a new alk test. I am having a problem right now where I have two test kits and both read vastly different numbers and I am running out of both of them!

 

At the moment I have a salifert and Seachem alk test. The Salifert reads 5.5 dkh the Seachem reads 8.4. I am using reef crystals and change 5 gallons twice a week (50 gallon display + sump). The tank is brand new and this will be the second week my live stock has transferred over.

 

I need to order a new alk test and am wondering what people are using. I use salifert for mag and calc with no problem but I have lost faith in their Alk. There is no way my tankis at 5.5 right now.

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5.5 and 8.4 are really far off. Have you tested the Salifert against the known dkh solution that comes with the test kit? Is it off?

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Just used the reference solution and it came back at 6 when its supposed to be 6.7. There is definitely something wrong with the salifert kit but its not off enough to account for descrepancy between the salifert and seachem tests.

 

Now I am nervous because I guess I should start dosing 2 part but I don't even have a reliable test kit to do so...

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I have been using Salifert for DkH, Ca, and Mg for years and have been happy with them. Maybe your Salifert test is old? It might be worth getting a new Salifert Alk kit, but if you don't want Salifert I know that many people like the Red Sea test kits as well.

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I have been using Salifert for DkH, Ca, and Mg for years and have been happy with them. Maybe your Salifert test is old? It might be worth getting a new Salifert Alk kit, but if you don't want Salifert I know that many people like the Red Sea test kits as well.

 

Thanks for the advice. I am going to do some research on Red Sea test kits and may go that route.

 

I used the last of my fluid to test the Seachem kit against its calibration fluid and it came back exactly correct. I am very conflicted on this one.

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I have recently changed from the Red Sea Alk Pro to the Salifert Alk test and I find the colour change is so much easier to read. The more recent Red Sea kits don't go from a distinct blue to red colour, it is more of a blue to orange/pink. The biggest thing to get used to is that the Red Sea kits take a reading based on how much titrant is USED (starting at 1ml and scaling down to where the plunger stops) where as the Salifert kit takes a reading based on how much titrant is LEFT (starting at 0ml and scaling up to where the plunger stops). It took me a few takes to figure out what I was doing wrong until I read the instructions properly. Double check you are reading the titrant syringe correctly with the Salifert kit or you could be getting a wildly incorrect result.

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I have recently changed from the Red Sea Alk Pro to the Salifert Alk test and I find the colour change is so much easier to read. The more recent Red Sea kits don't go from a distinct blue to red colour, it is more of a blue to orange/pink. The biggest thing to get used to is that the Red Sea kits take a reading based on how much titrant is USED (starting at 1ml and scaling down to where the plunger stops) where as the Salifert kit takes a reading based on how much titrant is LEFT (starting at 0ml and scaling up to where the plunger stops). It took me a few takes to figure out what I was doing wrong until I read the instructions properly. Double check you are reading the titrant syringe correctly with the Salifert kit or you could be getting a wildly incorrect result.

 

Interesting. One of my main complaints about the salifert kit (other than being inaccurate...) is that the color change is kind of hard to see exactly. Mine never turns orange. I will go from that light blue color to blue to dark blue then all of a sudden it starts turning slightly purple and its hard to know exactly where to call it a day.

 

My Salifert kit expires in 2019 but I have had it for at least a year so perhaps it has gone bad from me leaving it slightly open between testing one time or something.

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Interesting. One of my main complaints about the salifert kit is that the color change is kind of hard to see exactly. Mine never turns orange. I will go from that light blue color to blue to dark blue then all of a sudden it starts turning slightly purple and its hard to know exactly where to call it a day.

I have had that happen to me before. I tend to run a second test immediately after and get the correct reading the second time round. I have found that the issue tends to be residue left over from a previous test in the tube, even though I thoroughly clean them and dry them after use. Alk has always been the hardest test for me to master when it comes to getting a consistent test so if it looks off I always take a second test and take the second reading if it is closer to what it should be.

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NorthGaHillbilly

Another thing to think of, not sure that this would fix your problem tho, is I completely ignor the instructions when it says to just look at where the plunger is, as ive found the plunger can be at 1, but the trident will be anywhere from 8 to 8.5. I pull the trident to 8 each time, it might or might not be an "accurate number, but its consistant

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After doing some poking around it I found this awesome page. http://www.advancedaquarist.com/2007/8/review

 

Looks like Salifert and Seachem were about 10% off when compared to the lab grade testing unit. Given the Seachem is less expensive I may stick with that.

 

edit

 

This is from 2007 so maybe things have changed.

 

edit 2

 

Anyone using the Hanna Alk checker? I had one a while ago but I ended up returning it because I had nothing with problems with it. Every time I would try to use it I would get weird error messages on the screen.

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