HW Marinemix Reefer salt mix & potassium levels

Anybody in the club use HW Marinemix Reefer salt mix?????? Have you tested your potassium levels with this mix??? I just made the switch from Reef crystals to HW Marinemix Reefer salt - and using the Salifert test kit, I'm getting a reading of only 200 ppm (normal sea level is 390-410). I would like to test some additional samples - to confirm that it is a problem with my particular box. So, if you are using the mix, please let me know.

Here's complete details on what I have tested.

I made a switch at the beginning of the year from Reef Crystals to HW Marinemix Reefer Salt. Last week I tested my potassium levels and found they had dropped significantly from my target of 400 to anywhere from 290 to 350 in my 3 tanks. I then performed the test on my makeup water and got a reading of only 200.

Thinking this must be a mistake I tested the makeup water for the other major components and got salinity (1.026), calcium (415-425), and alk (don't remember for sure but in range of 8.5-9.5).

I use the Salifert test kit for potassium. Since it was almost empty, I ordered a new test kit and tested again and got the same results. I even had a bag of unused Reef Crystals, and tested it and got a result of 360.

As the HW Marinemix Reefer Salt is in one large bag (160 g makeup), I opened my second box of it and mixed it thoroughly (divided it between 3 buckets, mixed each, then recombined- and tested again - same results - @200.

My calibration fluid for my refractometer is old. It could be off a bit, but not that much. But, I've ordered a new bottle of that.

I contacted BRS (my source for the salt mix), but they said they weren't set-up to perform a test (They were happy to refund my money though for the salt mix).

I contacted the manufacturer and got a nice response that confirmed that the salt should have 400 ppm potassium. They thought it was strange that calcium and alk would be good, but potassium only half. They suggested that I get some calibration fluid - but I don't know where to obtain that.

So - I'm curious if anyone out there uses the HW Marinemix - and have you tested your makeup water for potassium? What are your results?

Anyone know where to get calibration fluid for a potassium test kit??

 

Did both of those things already. The manufacturer responded to my email that potassium should be at 400 ppm. And on the 2nd box I opened - I mixed it - what I thought was pretty good.

I also calibrated the refractometer with ro water in the interim. No change.

 

Great! Where are you located?

 

Are you planning to come to spring fest on Saturday? If so, want to bring a sample of your makeup water?

 

That would be great. I'd really appreciate it!

 

Thanks to @hart for bringing me a sample of his salt. I performed a test using his sample and came up with a potassium result of 400.

After further communications with HW, they identified a problem with their automated system which adds the potassium element to their salt mix - and they are fixing the problem. They are sending me an appropriate amt of potassium to make up for the low readings. Here was their response:

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Note from Jeanette: I have removed the additional details. The information was copied directly from my email. I did not realize when I did it, but the email contained a legal disclaimer about not sharing the email. So, I could paraphrase it, but not copy verbatem. By error.

 

I imagine its a huge deal. Although it may be true that being low is better than being high - as being 'high' can cause serious problems, I find the low potassium level to be an issue with coloration of SPS. Who knows how many boxes of the 'low' potassium level salt mix they have on the market and have sold - and the number of people that don't know that this is a problem.

 

I just now saw Randy's response.

Everyone - here is the response from Randy on my thread on Reef-2-Reef. HW Marinemix Reefer salt mix & potassium levels

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OMG, I lost interest in that ridiculous explanation when they uttered this total fabricated nonsense.

I mean, really, fess up to making a mistake. Don't compound it by saying things that are simply untrue.


Potassium has a molecular weight of 39.1 g/mole.
Potassium chloride has a molecular weight of 74.6 g/mole.

Consequently, KCl is 39.1/74.6 = 52.4% potassium by weight.


Potassium sulfate has a molecular weight of 174.3 g/mole.
Consequently, K2SO4 is (39.1 + 39.1)/174.3 = 44.9% potassium by weight.

Neither potassium chloride nor potassium sulfate typically form hydrates.

So there is just no sense to claiming that KCl has half the potassium of potassium sulfate, except that it seems to have 2 K ions in the formula.

Unbelievable.

 

Thanks for the offer, but I don't think it will be necessary. Using hart's sample, I'm able to conclude that my test kit is fine, and that the problem lies with the box of salt mix that I received.

 

That's a tough one. I go back and forth on the issue. I definitely see your point.

Maybe I'm just too much of an optimist. The other way I look at it is that they could have simply replied to me that they had a problem and it has been corrected. But they went a step further to try to give me an explanation on how it happened. They didn't have to do it. I think that part of their explanation was also impacted by a language difference. Now they should have been able to have someone with better English skills write the response, after all they are selling their product internationally. But the language in the response definitely had some translation issues.

Everyone will need to make their own conclusion. In my mind there is not a right or wrong answer whether I will continue to use this salt mix after the current box is exhausted.