HW Marinemix Reefer salt mix & potassium levels

[Jeanette]

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??

 

[Randy Holmes-Farley]

I'd personally be surprised if it is really that low, or if it is, its a bad batch. They claim much higher levels, and its easy (e.g., not expensive) to make it that way.

That said, I've not seen any recent hobbyist measurements.

 

[Jeanette]

I agree - I've very surprised. That's why I've been searching to find something wrong with my test - but haven't found anything yet. I'm trying to find someone locally that uses the mix so that I can get a sample of theirs. Although I've got the same results from 2 different boxes - they were both purchased at the same time, and thus could be from the same lot.

 

[jwshiver]

I use to use HW. When I tested it with Sailfert test kit it was 400.

 

[Jeanette]

I use to use HW. When I tested it with Sailfert test kit it was 400.

Thanks for the reply. That's good to hear.

 

[dragon99]

I switched to HW Reefer last month, but haven't checked my Potassium since the switch. Guess I'll be doing that tonight.

 

[Darth George]

Same here. Been using it for about a year and never tested the potassium levels. Will be now. My tank has never looked better though...

 

[Jeanette]

I will be looking forward to what you get for results. I just got new calibration fluid for my refractometer and calibrated it. Made up 4 gal of water and tested again. Got 250 ppm for potassium.

 

[Randy Holmes-Farley]

I will be looking forward to what you get for results. I just got new calibration fluid for my refractometer and calibrated it. Made up 4 gal of water and tested again. Got 250 ppm for potassium.

Mixing up a small amount from a bucket can lead to confusion if there is some nonuniform settling of the contents.

 

[dragon99]

Tank tested at 332ppm.
Last triton test came back @ 362mg/L, and following that result I dosed enough to raise it to 400, but that was ~3 months ago.

So best case, my potassium has dropped 30, worst case it's dropped 70. I made a small dose tonight (red sea colors B) and I'll retest tomorrow. Not planning a WC until Sunday, so I'll test a fresh mix then.

 

[Jeanette]

Mixing up a small amount from a bucket can lead to confusion if there is some nonuniform settling of the contents.

Usually I mix up a 12 gallon batch. The HW salt comes in a bag for preparing 160 gallons. Are there any recommendations on how to mix the salt (prior to adding it to RO water) to alleviate any problems of elements having settled? What I tried was to pour the salt into four 5 gallon buckets (a little into each bucket at a time - so each bucket rec'd salt from the bag about 4 times). Then I stirred the salt in each of the buckets. Finally I merged them back together - again a little at a time from each bucket.

 

[Randy Holmes-Farley]

Usually I mix up a 12 gallon batch. The HW salt comes in a bag for preparing 160 gallons. Are there any recommendations on how to mix the salt (prior to adding it to RO water) to alleviate any problems of elements having settled? What I tried was to pour the salt into four 5 gallon buckets (a little into each bucket at a time - so each bucket rec'd salt from the bag about 4 times). Then I stirred the salt in each of the buckets. Finally I merged them back together - again a little at a time from each bucket.

That might be good enough, depending on how you did it.

 

[dragon99]

So I tested a fresh mix tonight of ~18g and came out with 217ppm for Potassium. Tested twice w/ red sea.

 

[Randy Holmes-Farley]

Have you gotten "normal" readings with this kit?

 

[dragon99]

Fair question. My tank tested at 332, then 360 a couple days after dosing. I expected to see only ~350 based on the amount I dosed. So it was close, but not perfect.

I plan to mix and re-test with some IO salt tonight. Hopefully that sheds some light on whether the salt or my testing is faulty.

 

[daelie]

Ah, I knew I couldn't be the only one.

I've been using HW for about 2 years-ish. I buy once a year during black friday from BRS. The first two years it was really solid, and I never had any trouble. I run two tanks, one of which gets a weekly water change and one that really never gets a water change. I noticed some corals not extending their polyps as much and montis starting to look dull in the one getting water changes. This thing had been solid for months and months, and I hadn't added anything or changed anything. I tested the potassium in the tank and it was 300, which struck me as odd so I tested my non-water change tank and got 390. Hmm I thought. So I mixed up 5 gallons of new salt, and dang, 310 ppm. I retested a friend's freshly mixed 5 gallon of HW, and got 400.

I think there must be a bad batch floating around. I buy two boxes each black friday that lasts a year and this is the first time I've ever seen a parameter be off on them. I bought a new box, and I use the bad batch for culturing phytoplankton and copepods now. The new box tests at 390, as well as another local using AF Probiotic, which I tested at 390 as well. So the 310 seems to be believable.

 

[dragon99]

IO tested @ 410ppm

So it's not the test kit. HW has a bad batch.:mad:

 

[Randy Holmes-Farley]

That's unfortunate.

 

[hart24601]

Usually I mix up a 12 gallon batch. The HW salt comes in a bag for preparing 160 gallons. Are there any recommendations on how to mix the salt (prior to adding it to RO water) to alleviate any problems of elements having settled? What I tried was to pour the salt into four 5 gallon buckets (a little into each bucket at a time - so each bucket rec'd salt from the bag about 4 times). Then I stirred the salt in each of the buckets. Finally I merged them back together - again a little at a time from each bucket.

Have you had a chance to test the salt from my box of Marinemix I gave you are FragFest yet?

 

[Jeanette]

Just finished making up two 4-gallon buckets of makeup water. One contained the salt sample that I received from @hart24601 . The other was from the box I received from BRS. Potassium level for the salt sample from Hart came in right at 400.
Potassium level for the other sample measured 250.

I too got my salt from BRS on their Black Friday sale. 3 boxes of it! They have refunded me my money. I'd really like to try this salt, but don't know what to do next. I don't see anything on the box that has any reference to a lot number.

One interesting thing I noticed was that the salt sample I got from Hart, was a difference in the texture of the salt. My box from BRS was very fine - like table salt. The sample from Hart seemed almost as if it had a bit of moisture left in it. Not sure how to describe it.

@daelie - Did you get your new box of salt (the one that tested good on potassium) from BRS also? Did you talk to them about the problem? If not, it might be good to do so. Although they refunded my money w/o any problem, I couldn't get them to perform a test on the potassium level.