Alkalinity test kit readings

[gregr]

Anybody use a Salifert alkalinty test kit? I have been for a while now and I was getting worried that high alkalinity might be hurting my corals. I heard from a couple different people that the Salifert kit was hinky. Well, today I got a Sera test kit. It's not as precise as the Salifert but the results were significantly different. With the new kit the dkh is 9.5-10. The Salifert consistently reads 12.2-12.8. Big difference!

[charlie]

I use Salifert Greg, and I am not having that problem. If anything, mine is low, but I think it is pretty accurate, haven't compared anything. Is it a new kit?

[gregr]

It's maybe 6 months old. It's always given me 12's, even when it was new. The two people that told me Salifert reads high are extremely experienced- in fact, both of them make their living in the business (not selling test kits though!).

[charlie]

I misspoke before. I had some Elos test kits about a year ago and they tested alk about the same the Salifert kit I had at the time. I don't know, I have taken my water over to Kevin before, and his Salifert kit read the same as my Elos and Salifert. I don't know?????

[gregr]

Well, I guess it's not an absolute then. But look at my system- calcium reactor that has been working consistently for a long time, kalk drip (5 gallon jug lasts about 5 days), calcium pretty steadily around 420, pH 8.1-8.3. Would you expect alkalinity over 12 with a system like that? I can't figure it out, but then, I'm no chemistry whiz. I did some searching for how to solve high alk problems and most of what I found was for systems that had high alk and low calcium. So I wasn't sure what to do because if I added calcium chloride (what one expert says to do in cases of high alk/low calcium) it might shoot the calcium too high. Then I got this new test kit and thought I might not have a problem after all.

[charlie]

Have you tried taking a couple of water samples to the stores near you?

[gregr]

Been meaning to do that... The store I go to most often uses Salifert kits.
By the way- that needle valve we were talking about-- I changed out the media in the reactor 4 days ago and the drip rate has stayed consistent since then.

[charlie]

That is good knowledge. That is the first one from US Plastics?

Do they have an elos kit they would break open for you?

[Ninong]

What is the expiration date on the Salifert alkalinity test kit? For the past five years or so Salifert has been putting expiration dates on all their test kits. Prior to that, I purchased boron test kits that turned out to be more than six years old and a phoshate test kit that was too old to work. Not sure how old the phosphate test kit was, I just know that when I gave the president of Salifert the batch numbers, he told me the kit was too old to provide useful results. He promised to have the vendor send me a replacement. I received a new, fresh phosphate test kit two months later. The replacement boron test kit they sent me was another one that was more than six years old. I ended up getting a refund on the boron test kit because they didn't have any fresh ones in the U.S. at that time.

My experience with Salifert test kits has been mixed. Usually they were okay most of the time. My experience with LaMotte test kits was always good. For calcium and alkalinity, I used only LaMotte.

[gregr]

I'll have to brush up on my Nordic language skills but I think the expiration date is 12/12
Tomorrow I'm going to visit the LFS and will take some water to get it tested there. I've never seen LaMotte kits locally- have to see about buying them on-line. Thanks Ninong.

[Ninong]

Haha! I don't think Dutch is considered a Nordic language. Anyway, December 2012 is more than three years from today. That seems like a long, long time to me. I just checked the shelf life of the alkalinity titrant LaMotte uses in their alkalinity test kits (the ones I'm familiar with) and it's 24 months. Maybe Salifert's alkalinity test kits are different. LaMotte's test kits are coded with the week and year of manufacture as well as the lot number. Their website has a handy shelf-life chart for all of their reagents and titrants. Some of their test kits have a shelf life of only six months and others last 18 months, 24 months or even 36 months, but none of them has a shelf life longer than 36 months.

Anyway, if the expiration date is still more than three years ago (according to Salifert), then it sounds like the test kits must be fresh.

BTW, 12.8 dKH is not an unreasonably high reading on alkalinity, provided your calcium levels are not depressed. Some people actually shoot for a range of 10-12 dKH, while others prefer 8-10 dKH. A lot depends on where you're keeping calcium and magnesium.

[gregr]

Dutch... couldn't remember where they were from so I put "Nordic" down and embarassed myself even more
The last part of your post is what I was looking to hear. I've read before that high-ish dKH numbers might even be good, assuming you want fast coral growth, but I wonder if having your dKH up around 12-13 does not exacerbate sps tip burning. About a week ago my calcium reactor clogged because the media needed changing. So, for about two days the reactor was not consistent. On the third day, when I was changing the media I noticed a couple of burnt tips on one acro and another, a red mille, has an area where the tissue died. Both corals appear to be super healthy otherwise (great polyp extension and color) and from what I can see both corals have not had any more tissue loss. Do you think it was merely the abrupt change in reactor output that caused the problem? Do you think the high alk was a contributing factor? And if yes, how can I get the dKH down without raising the calcium too high? My limited understanding is that if I want to lower the alk I should add caclium chloride.
Sorry for the longwinded reply and questions

[charlie]

The high alk will come down on it's own Greg, over time. At least that is what I have found. Ninong always liked his alk and calcium alot higher than I prefer it!!!

[Ninong]

A sudden spike in alkalinity is always harmful to corals, especially mushrooms. The only question is whether or not the harm is apparent.

I wouldn't actually recommend maintainly alkalinity above 12 dKH. I always tried to keep mine between 10-12 dKH. It was usually closer to 10 than to 12. I do know at least one successful hobbyist who likes to keep his alkalinity between 12-14 dKH but he's definitely not in the mainstream for lots of reasons. He maintains his magnesium around 1500 ppm, and calcium around 500 ppm. He also has a very high flow SPS-dominated tank with very high lighting. He uses one of those fancy bio-additive methods. I can't remember if it's the German one or the Italian one. Anyway, it can be done, I guess, but that's not for the faint of heart.

Randy Holmes-Farley has posted that alkalinity below 14 dKH is not a problem unless it depresses calcium. According to Randy, alkalinity has to get above 18 dKH to really cause problems. Personally, I would definitely start taking corrective action at 14 dKH but I wouldn't freak out over 12.8 dKH. As I'm sure you already know, calcium, alkalinity and magnesium are all related and are best kept in balance. Most hobbyists prefer to maintain alkalinity higher than NSW levels (2.5 mEq/L, 7 dKH) just as a safety measure. I didn't like seeing mine fall below 9 dKH because I was afraid bad things would happen to me that had never happened before, like hair algae, for instance. I always tried to maintain 10-12 dKH alk, 475 ppm Ca and 1300-1350 Mg.



P.S. -- If you want to go all natural, then 425 ppm Ca, 1300 ppm Mg and 8 dKH alk (slightly above NSW levels of 7 dKH) would be perfectly acceptable. Anything below that would be considered unnatural.

[gregr]

That's what I've read but it's not what I've experienced- the dKH in my tank seems to always be in the 12 range per Salifert. I'll start keeping track of it with the Sera kit now though.

[gregr]

That last response was to Charlie, obvisously. Ninong- I will keep all that in mind. I haven't tested the magnesium in a while- it was always around 1350 and I just stopped testing because it was so consistent. Will test it today. I use Ocean Pure Pro salt and the mag/calcium has been consistently great.
More later- gotta head out to run some errands now.

[Ninong]

It's quite possible that there is something wrong with your Salifert alkalinity test kit. If it measures 12.8 dKH and another brand of test kit measures considerably lower, then one of them is off.

[zhenya]

I use Ocean Pure Pro salt and the mag/calcium has been consistently great.

Greg, have you tried testing freshly mixed water with both kits? It would be interesting to see if the difference was the same on the Sera kit.

As far as test results could be higher with Salifert's test kit it is nothing surprizing to me. I once had a calcium test kit that read consistently 500ppm of Ca. I mean it was 500 ppm no matter what I tested...
Once I bought another kit it was all solved. Sheesh...

Now, on the levels themselves. I used to keep my Alkalinity (when I had sps dominated tank) at 12 dkh most of the time with Calcium around 425-450 ppm. Never had any problems at all unless you think corals growing out of the water are the problems. However, I was told by few very respected people in the hobby that it is not needed, so I let it drop naturally by slowing down my reactor and kalk additions. And then again, water change will do wonders. ;)

[Ninong]

Gene,

Not to derail Greg's thread, but it is sort of related. Remember back around 18 months ago when the Salifert sponsor's forum was 'removed' from RC because of certain threads pointing out problems with their test kits, one of which was their alkalinity test kit? And then it wasn't very long after that before Habib Sekha disappeared from the board. He hasn't been on RC in more than a year now. Whatever happened to him? Surely you must have heard something at one of those conventions.

You can't even search for those threads anymore because that forum no longer 'exists.' It was removed at the request of the sponsor.

[gregr]

That's too bad- I liked Habib and thought he was a good guy. Not sure if you knew it or not but I moderated the photography forum on RC for a long time.
Anyhow- good idea Gene- I'll test some new saltwater with both kits and see what comes up. I bet they will be different by a point or two. Will post the results here in a few days. I have a feeling the Ocean Pure salt has fairly high dKH to start with- that would help explain why I get temporary lower alk occasionally, like when I started dripping kalk. But it seems to always creep back up. I wouldn't worry about it at all if it weren't for the burnt acro tips I get every once in a while.