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Got my Hanna Alk checker today!


Harold B

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Well I got my colorimeter today and my Alk that I always thought was 10 dkh turns out to be 8.5 dkh or 3.06 meg/l and here I always thought I ran my Alk a little high. So that means if I was trying to keep it at 8 by a chemical test kit it would really be 6.5 dkh not cool.

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I dont know about that. But I have been waiting for this for over 3 weeks and things were supposed to be figured out and all I know is that mine is indeed consistantly 1.2 dkh off (low) from my API test kit (brand new). Which one does a guy believe? Does anyone know of something I can use as a control sample that has a for sure dkh value to compare these against?

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I know I thought I was going to purchase this also (I like gadgets) and have the phosphate meter that works great!

 

I use a DIY volumetric titration that uses a standard sulfuric acid and a calibrated PH meter (7 and 4 instead of 7 and 10). You drip the acid into 100ml of tank water until the ph meter reads 4.2 (this is where all of the carbonate ions have been converted) and you can use a simple formula to tell what your alk is. It only takes a couple of minutes but I thought the alk meter was going to be easier... but I don't know now. It seems like different lots of reagents in the alk meter have been giving different results, most are reading about 1-2 dkh off of hobby kits. Some people have been reporting they are getting close results shaking the samples for a couple of minutes instead of 30 seconds stated in the instructions, but they are still a little low.

 

If you read boomer (chemistry expert) on RCs responses in several threads, he details that most hobby kits including the hanna meter are only reading alk down to a ph of 4.5, not the correct ph of 4.2 needed with saltwater. This is ok as long as you realize that your kit is going to run about 10% low. The salifert test kit is designed to read down to 4.2 so the results are very different for those who are using the salifert against the hanna.

 

If you want to bring your meter over, we can do a ph titration against your meter with the same sample water and you can see how far your meter is off.

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I just read all 100+ posts. I do not believe that the hanna meter is worthless. There may be a problem or two with it but it appears that it may have been a combination of the amount of time to dissolve the reagents and the lot of the reagents. It also appears that the testers are reading consistant with all the other test kits out there except salifert. Now it is known that salifert test kits do read higher than the rest IMO you cannot say that salifert is the only accurate one.

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Mike has made a valid point that salifert is the only test kit to measure down to the ph of 4.2. With understanding this it would be quite feasible to get consistant reliable readings with the hanna tester. The fact that they are different is not as big of a concern as the change in the value.

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I do not believe that the hanna meter is worthless

 

That was being a little harsh, I was excited to see this and the nitrate monitor out and was quite disappointed to see the problems it is having.

 

I guess if it proves to be consistent, it could work as long as you know it is reading low.

 

but i might be able to come up there tomorrow

 

I work tomorrow all day, but have a 3 day weekend so you are welcome to come over Sat, Sun, or Monday.

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