Prepared Kent SW has a Alk of 0.6 dkh. Is this normal for SW mixes?

[doccarbon]

Due to problems maintaining the alkalinity of water in my aquarium I recently begain testing the SW I use for water changes. I am using Kent salt, RO water from the lab at work, and Salifert Alk test kit. The last two tests that I took at SG 1.025 and aerating for 24 hours gave me a Alk reading of 0.6 dKH. It only takes 3 drops (low resolution) to get color change.

It is normal for prepared SW to have such low alkalinity values? I thought that most salt would bring the carbonate levels up to near normal. Should I consider changing my salt to another brand? Is there something I am overlooking?

Thank you
Tim

[Randy Holmes-Farley]

0.6 dKH?

I expect that is a testing error of some sort, but it could be a huge error in the salt mix.

How do you measure salinity?

[doccarbon]

Randy,

I measure salinity using a refractometer. My mistake Alk should have been stated as meq/l, but that still seems low.

[Habib]

IIRC there was a similar thread recently and the poster did not understand why the pH was still around 8.

I suggested that it might be due to borate and the bicarbonate/carbonate might have been missing from that batch.

IIRC it was in the RD forum.

[Habib]

Here is the thread... two different brand of alk kits gave a similar low value (2dKH):

http://archive.reefcentral.com/forum...ghlight=borate

[Randy Holmes-Farley]

That would certainly be a huge error in formulation.

If you want to try using it, I'd boost the alkalinity with baking soda. This calculator shows how much to use:

Reef chemicals calculator
http://home.comcast.net/~jdieck1/chem_calc3.html

[boxfishpooalot]

Originally posted by Habib
IIRC there was a similar thread recently and the poster did not understand why the pH was still around 8.

I suggested that it might be due to borate and the bicarbonate/carbonate might have been missing from that batch.

IIRC it was in the RD forum.

I wonder if tap water could contain enough Co2 in it to lower ph on freshly mixed saltwater? That could be his problem also? Or even fresh RO water would contain Co2 if city water is high in it.

[doccarbon]

Thank you everyone for your replies. Guess I will dose with buffer and see if that will get the alk up where it belongs. What a eye opener, very surprised alk could be that low. Unfortunately, I just cracked open this 200 gallon bucket, so I still have 3/4s left. Believe I will be going to IO salt next.

[Randy Holmes-Farley]

I wonder if tap water could contain enough Co2 in it to lower ph on freshly mixed saltwater? That could be his problem also? Or even fresh RO water would contain Co2 if city water is high in it.

CO2 can lower pH, but not alkalinity. Tap water could be acidic in other ways that deplete alkalinity, but not that much.
Believe I will be going to IO salt next.

Sounds good. If the salt mix or the corals/fish seem to react oddly, you might stop using it as it is hard to know if sodium bicarbonate is all they left out, and perhaps the whole mix is odd in some way.

[scyphozoa]

Recently I used a brand new batch of Kent salt and had the same problems with alk. I noticed that the logo/name on the packaging is now yellow---do you think they changed the formulation of their product? (I too may have to switch back to IO.)

[Randy Holmes-Farley]

I don't know what might have happened. It sounds like a manufacturing problem, rather than an intended change.

[turbodiesel01]

Just tested my new batch of Kent also. Same problem. No wonder my tank alk has been crashing lately despite my ca reactor wide open and dosing B ionic.
GRRR

[aquaconnect]

I have super high calcium and 1.9dkh from my batch. I've called Kent, no responce. Emailed then, they said to send them 1lb, like I'm stupid and don't know what's going on. I'm great friends with an individual who owns and sells Kent. He and I both have had super bad problems maintaining calcium, ect, and thought it was our reactors. Boy were we dead wrong. Kent's rep told him they were aware of the problem and went into detail. They told me the exact opposite. Here's the letter I got, after already knowing what they told the owner of the retail store: RC posted link

http://archive.reefcentral.com/forum...hreadid=767696

[Randy Holmes-Farley]

Thanks for the link to the letter. A bit of a disappointment. Mistakes happen, and it is always better to fess up and try to make amends than hide it, IMO.

[E-A-G-L-E-S]

last batch@1.025 w/refrac.)
calc. 380
7dkh
ph 8.1

*mine was a 50g. bag though, not the 200g. bucket........does that have anything to do with it, or did i just not get some of the bad batch by luck?

[Randy Holmes-Farley]

I don't know, but those values seem fine.

[E-A-G-L-E-S]

that frown should have been a smile, sorry

[Randy Holmes-Farley]

OK, that makes sense.

[BrianPlankis]

I recently bought Kent (200 gal bucket), about 2 months ago. Last testing of the salt was about 2 weeks ago:

SG: 1.026 (refractometer)
Ca: 390 ppm
Mg: 1300 ppm
Alk: 9.0 dkH

All Salifert kits

But I will watch my next bucket values carefully! Unless I witness the low Alk I'm sticking with Kent, my corals do great in it.

Brian

[aquaconnect]

Well, the gentleman from Kent finally called me back after a week today and says he's going to send me some 'Kent Merchandise' for all my trouble and admitted knowing there was a 'problem' on the phone. I'll let everyone know how it turns out.

[Randy Holmes-Farley]

I hope it is a useful product that they send. When I had some crappy Coralife mh bulbs explode years ago, all they sent me was salt mix which I never used in a tank but did use in an ice cream maker.
They never even replaced the bulb.

[silverfishar]

Please post what Kent sends you as reparation. A number of people are returning product, including me (0.9 dKH on my bucket) but haven't heard what we can expect yet.

[tridacna5]

Kent recently switched from having salt made at the Ohio facility where Instant Ocean is made to the facility that Coralife uses in California. Only the new buckets (not bags) seem to be the problem, all the lettering is in yellow as opposed to the old buckets which have white lettering.

The dKH does come out to 0.9 when mixed at 35 ppt, but as Randy mentioned, this can be offset by adding some baking soda.

I have been using Kent salt in my store for 6 years and have never had a problem similar to this. Kent is a great company and I am sure they will keep a better eye on QC in the future.

[silverfishar]

I would have to wonder, though, if the components that drive alkalinity are off that far, what else is that far off. I don't claim to know enough to know exactly what that is, but that might be the point. If anything is that far off, can I trust the rest of the chemistry in the components I can't test for?

[Randy Holmes-Farley]

If anything is that far off, can I trust the rest of the chemistry in the components I can't test for?

Yes, that would be my concern as well. Did they leave out one thing (sodium bicarbonate), or did they leave out more than 1 component, which you may not know about.