High Ca and Mg in Tunze Reef Excel Salt?

[austinaqualung]

I recently bought a bucket of Tunze Reef Excel Lab Grade Salt. After mixing about 40 gallons (using RODI with 0 TDS) to SG of 1.025 and circulating it for 24 hours, I measured the alk at 7dKH. Seemed kind of low, since I heard others were getting around 9.5. I then measured Ca, and it was really high at about 600. I then measured Mg at around 2000 (again really high). I measured alk, Ca, and Mg twice each, and got the same readings again (24 hours later).

I was skeptical of these readings, so using the same testing kits (Salifert), I measured my tank saltwater, and it measured fine with alk=9dKH, Ca=450, and Mg=1350, so I doubt it is a problem with the test kits (plus I've been using the tests kits for months without any issues). All test kits have been purchased in the last 2 months, so they are not close to expiring.

Roger, any thoughts on what the problem is? Seems like a bad batch of salt. Have you seen any other issues with this salt?

 

[rvitko]

Well, we only have received one batch of salt and it is made in an ISO certified facility, everyone should have the exact same salt. I have to suspect something is wrong with the kit or the sample collection.

 

[Jar*Head]

Good morning, What did you use to measure your salinity? Can you share with us the temp of your salt mix. Have you try to test the pH before you test for Ca, Alk, and Mg.

IMO, the number you provided is very abnormal .

 

[austinaqualung]

Good morning Jar*Head. I measured the salinity using a refractometer and a conductivity meter. Both showed a reading of 1.025. I'll measure the temp of the salt mix this evening, but I suspect it is around 70-75F. I measured the pH at 8.1.

I agree, the numbers seem pretty abnormal.

 

[Jar*Head]

Austin, do you calibrate your Refractormeter everytime you test the salinity? I always rinse mine out with RO/DI water making sure it at 0 before i do any testing.

Another tip, make sure you mix the salt bucket or bag real well before you start to mix. Sometime stuff get shifting during shipping. I did that with all my salt... Either roll it around in the parking lot for a few min or take it out, shake it really good then start to mix.

Something else that i learn in the past. Make sure you add water, get the temp to where it suppose to be, add circulation pump then salt. Some people put the salt in the bucket first, then add water. This will cause recipretation

 

[austinaqualung]

Jar*Head, thanks for the suggestions.

I didn't calibrate the refractometer, since it correlated with the conductivity meter almost exactly.

I didn't mix the bucket before mixing. I wasn't aware that the stuff would shift that much. I'll try that, but since I've already used about 1/3 of the bucket, it may not help.

When I mixed the batch, I added the water first along with the circulation pump, and then the salt. I don't see any precipitation at the bottom of the can.

 

[rvitko]

Logically if the reading was correct there would be precipitation, it wouldn't be possible to have that much dissolved. I would guess either some undissolved salt got in the test tube or there was a residue from a previous test.

 

[tbone28]

Subscribed. About to order this salt.

 

[Jar*Head]

Terry, you have use this salt before. What is your parameter after the mix? Don't tell me you did not test the new salt either....

 

[tbone28]

mine came out really nice, as did all the other people who got the free bag. I can't remember exactly now

Ca 420
Alk 8
pH 8.1
Mg 1300

something like that

I really hope this measurement was done in error, because I can't deal with bad batches of Tunze salt at this price.

 

[rvitko]

As I said, only one batch has been made, every bag or bucket we have came from that batch. The salt is made by Hans Weigandts and I can't imagine there is any variation. I think there is another explanation for this. Everyone who got a sample bag from this same shipment/lot posted very similar results.

 

[austinaqualung]

Well, I did a few more measurements after getting home from work. Water temp = 74F. Ca = 580. Didn't bother with measuring Mg, since the Ca was pretty much the same as before. I rinsed out the test tube several times before testing. And I confirmed that the mixing can was very clear with no detectable residue.

Like I said, Ca, Mg, and alk measure fine on my display tank, so I don't think it is the test kits.

When I have some time this weekend, I'll thoroughly mix the salt in the bucket before adding it to any water (as Jar suggested), and I'll mix up a couple of gallons. Maybe it settled in the bucket. Hopefully that will give me the same results that everyone else is seeing...

 

[rvitko]

These levels excede the amount that the water could hold in solution. You should have a precipitation if they are correct. I would ask that you bring a sample to myself, Brian at Kingfish or Bruce at AquaTek for verification with a different brand of test kits, I would bring one cup of the dry salt. Brian uses Elos, Bruce uses Machery Nagel Calcium and Seachem Magnesium and I would be using the same. I contacted Mr. Tunze this morning and he felt some testing error has occurred. It is possible for salt to settle with the lighter salts on top and Mg would definitely be a lighter salt and in an ideal world you use the entire container at once to avoid this issue but the case you present is extreme. I have used hW Marinemix exclusively until we came out with this new salt and never noted any variation between batches. hW Marinemix is what the majority of labs use in testing off shore oil well equipment for EPA certification and what the majority of institutions working with cephalopods use for just the reason, it is very consistent. This salt is made at the same factory by the same processes only with some changes in the formula to better suit the needs of stony corals.

 

[austinaqualung]

I guess since I'm using a circulation pump, the precipitation could be floating in the water rather than at the bottom of the can. I talked to Bruce earlier this week about this issue, and he referred me to you, so I can bring over to your place some of the water and dry salt. Just PM me when would be a good time as well as where.

 

[rvitko]

I don't have a Mg test so I would need to go to AquaTek to get one or use theirs. I also don't have RO water here which I would need to use the Machery Nagel CA test. You could drop off a sample here but I wouldn't be able to test it on site. 512-833-7546, just call first but I should be here Mon-Fri 9:30-5:30 unless I am running an errand or getting lunch.

 

[rvitko]

I just spoke to Bruce and he is willing to test it and he has everything he needs there. Bruce is probably the best since he actually has a Masters degree in Limnology and spent many years testing water professionally for the state.

 

[austinaqualung]

Ok, I'll bring some over to Bruce to test either tomorrow or Sat. Thanks.

 

[Jar*Head]

Austin, i don't mind doing the test for you using Elos test kit on everything and Hanna on PO4 but it doesn't worth your shipping cost.

 

[tbone28]

Thanks for being willing to test your salt, austinaqualung. I"m sure many are curious about the results. Like Roger mentioned, those of us who received the free bag were all very close in numbers.

 

[Jar*Head]

I should have the result for the Tunze salt soon.