Accuracy of Salifert test kits (quality control issues found)

[Rascal]

I picked up a new KH kit (K2) yesterday b/c my old one (K1) was getting low and I have been having some issues (more later). Turns out it was the exact same batch # - 1207-D on the reagent I think. Guess what? In back-to-back tests with each kit they turned out to be 1.5 KH off, with the older kit being higher than the new one. Funny thing is, when I first got K1, I tested it against what was left in the kit I was using at the time, another members brand new Salifert kit with a different batch #, and my salt mix, and I was convinced it was spot on. Towards the end of the bottle I started to have strong suspicions it was testing at least 1 Kh high. Based on the way each kit tests my salt mix, I now believe I was right. Somehow I think it started getting higher as it got older.

 

To be fair, I had gotten in the habit of squirting the unused portion of reagent back into the bottle after each test, so contamination is a very real possibility.

 

To address Chip's point, the root of my problem has nothing to do with test kits. I am afflicted with a POS Milwaukee regulator/bubble counter on my Ca. Reactor. It takes forever to get it dialed in, then it works great for a few months, then it sticks and takes forever to get dialed in again. When it is working correctly, I don't think it really matters that my test kit may be off by a point or so. As long as the levels are stable and within range (I aim for 11 Kh) it shouldn't cause any harm. The frustration with the test kits comes when I have a problem and I am trying to figure out just how bad that problem is. For example, my bubble counter decided to give me problems about a week before I left for vacation. I thought I had it fixed before I left town, but it turns out I didn't. When I came back the bubble count was like 1 every 10 sec and my Kh (with K1), was 7.8. That is bad. Corrective actions were taken. I'm not sure I would have done anything differently if I had known it was really 6.3 Kh instead, but at least I wouldn't have had any doubts about why my zoas weren't looking so hot and I am seeing a little bleaching and/or STN (can't tell yet) on my Chip's Acro and one of my Monti Caps. :(

[Valab]

I'm not up-to-date on the status of the Salifert Alk test kits, but it should be possible to use Arm & Hammer baking soda and RO/DI water to make a reliable alkalinity standard. I suspect that quality control on A&H baking soda is darn good since it is 'food grade'.

 

On a separate note, www.armandhammer.com has one of the most annoying splash pages I've ever seen. Even after hitting 'skip', Jill continues to pester you!

Edited August 22, 2007 by Valab

[flowerseller]

First offf,

"Chip's acro" is not "MY" = (Chip- flowerseller) namesake acro as many have or may think or used to think.

I understand it was lovingly named after a guy at ORA named Chip.

 

second offf

I have always squirted the left over KH reagent back in the container. I've thought of the issue you mentioned, just never acted on it.

I have two kits with the same batch and get the same readings from both, give or take a drop one way or the other

What do others do?

I know what many do because we do the same thing.

 

blast off

I'm just unsure which to believe because all the noted reefers, including myself, on this and other boards have suggested Salifert as the test to believe if two different where used with different end results.

 

We had confirmed differences with LaMotte Ca test kits back in the early/mid 90's testing same water with different kits even switching kits and testers around.

 

I play at a higher ALK than many and higher than some of our "experts" so as long as my kits continue to read near that, I feel comfortable.

Bottom line, if I had a test that some did even in a issue mode, I would not jump to dump and make a bunch of drastic changes.

 

You will be hard pressed to find a better solution to almost every non pest issue than remaining on a good routine water exchange schedule. Hands down!

 

In the event of an obvious issue, stepping up that schedule slightly, but not massively, is the next best course of action. As most cases I would not change more than 20% every other day.

I have rarely suggested much more radical exchange but IMO they were merritted based upon PO and not from some discription given over the web.

I would do this myself and not be as concerned with what any test showed, if I even tested, during it also.

I'm also saying this KNOWING, I have much more high $ value in large and long term colonies than 90% of those I know.

Some of these I've had 2x longer than some advise givers have even been in the hobby itself.

Not that I'm an expert, I am experienced, but if anyone ever wonders why I don't jump up to offer advise on a RTN issue it's because I have not seen it. It has nothing to do with "post count" either because I've been active on this board a long time so post count comes with the territory.

Not an attempt to belittle any member or is it out of arrogance either.

 

I just don't know which kit to honestly believe.

[dandy7200]

Chip gives good advice here. Low alk is bad for corals. Alk swings are worse for them. If you happen to find your alk low, correct it slowly. Nothing is going to kill a stressed coral faster than a big alk swing after being stressed from low alk in the first place (well a heat wave followed by a power outage in my case ). I found my alk was in the low 6's or even the high 5's for a period of several months, while I lost some things it was slow. I made the correction over the period of about a month to 8dkh and am now working on getting it back to 10dkh over the next month.

 

FWIW, you can make a reference solution with distilled water and baking soda. It is 0.9 grams of soda to 1 gallon of distilled water. I have no accurate way to weigh 0.9g though and the local CVS looked at me like I had bugs coming out of my head when I asked them to weigh it out for me. I could measure 9.0g accurately and add it to 10 gallons of water but what would I do with 10 gallons of solution..........

[Rascal]

First offf,

"Chip's acro" is not "MY" = (Chip- flowerseller) namesake acro as many have or may think or used to think.

 

LOL. Yeah, I know. It is a pretty nice looking coral to have associated with one's name, though.

 

second offf

I have always squirted the left over KH reagent back in the container. I've thought of the issue you mentioned, just never acted on it.

I have two kits with the same batch and get the same readings from both, give or take a drop one way or the other

What do others do?

I know what many do because we do the same thing.

 

I've never even looked at batch numbers before. My method has been to buy a new kit before the old one runs out, make sure they both test the same (or close), and then start using the new one when the old one ran out. I've never had them come up that far apart before.

 

I'm not ready to dump Salifert either. As I said, my real problem has more to do with a screwed up bubble counter than any test kit. When my reactor is working properly and keeping everything stable, +/- 1 or KH is probably good enough for me.

 

I found my alk was in the low 6's or even the high 5's for a period of several months, while I lost some things it was slow. I made the correction over the period of about a month to 8dkh and am now working on getting it back to 10dkh over the next month.

 

What if the drop is quicker and less prolonged. For example, mine had been steady at 10-12 for several months, then dropped to 5-6 in a matter of 6 days. In that case would it make sense to act more quickly to bring the levels back up to what everything had been accustomed to?

[dandy7200]

Well I git my 6.5dkh reference solution today.

 

Salifert Kit #1 reads 5.5dkh

Salifert Kit #2 reads 7.5dkh

Salifert Kit #3 reads 7.5dkh

Lamotte kit reads 6.5dkh

 

 

My feelings about the results are this: I may have been over titriting my test, I think this because of the pictures Habib has provided and the new kit I got with the reference solution in it test at 1dkh higher than the reference solution. So if I were titriting to the correct endpoint the results would look like this:

 

Kit #1 reads 4.5dkh

Kit #2 reads 6.5dkh

Kit #3 reads 6.5dkh

 

So the kit I was having problems with and tank problems as well looks to be indeed faulty while the two newer kits read spot on (if I could see the color change at 6.5dkh). I don't see the color change clearly at 6.5dkh with the Salifert kits, while I do see it clearly with the Lamotte kit. Habib needs to include a color card with his test kits since "first noticeable color change" is vague at best.

 

For now I'll stick with Lamotte since I can see a clear color change and it corresponds to the reference solution.

[Almon]

I thought you said your test kit was reading "high"? But Kit 1 is now reading low?

[flowerseller]

Rascal

My Alk can shift 2 points over the course of less than a week so I would adjust it back up.

 

Dan

How did you get your referance solution?

Can I test my kit against it?

Have you been keeping your KH at the low end to begin with?

 

 

 

I feel, and no one has confirmed this as a good thing other than me, that at a higher ALK range, a few point swing up or down is not nearly the issue as if you were at the lower end of the range to begin with. I figure at the lower end, it's a higher % change than being at the higher end would make it. Make sense?

I would not consider having my ALK any lower than 9ish to begin with anyway, but that's just me. I prefer between 10&14 and Ca in the 390/410 range.

Now if RHF said I should then I would invite him over to test my water and see what I don't appear to be having issues with by keeping it were I do.

 

That said, now I can't wait to see where I have really been keeping it.

 

 

Now if RHF said I should then I would invite him over to test my water and see what I don't appear to be having issues with by keeping it were I do.

 

That said, now I can't wait to see where I have really been keeping it.

 

Or I should say were I think I have been keeping it according to my Salifer test kit,

[YBeNormal]

I received my replacement Alk test kit today with the reference sample. I haven't had a chance to check it against my older test kits though. Maybe later tonight or tomorrow. I still can't figure out why the reference sample is at 6.5 though. Any idea why Salifert didn't go with a higher dKH?

 

IRT to which test kit to believe if two of them give different readings--I say neither one! Try a third test kit and go with best two out of three.

[Rascal]

Rascal

My Alk can shift 2 points over the course of less than a week so I would adjust it back up.

 

But with a 5 point drop over a week how quickly would you adjust it back up? I did 1 point a day, figuring that the stress of the swing was offset but the advantage to getting the Alk back to the level that everything had become accustomed to.

 

FWIW, I also have chosen to keep Alk at a range significantly higher than NSW, and in my mind episodes like my current one provide an additional reason for it. At 11 KH, I have a considerable buffer zone before things get really really bad. If I had lost 5 KH from a starting point of 8.5 I think I would be looking at a lot of white sticks in my tank right now.

 

Back on topic with the test kits, Dan's posts have convinced me that it is probably worth it to get a Lamotte kit. I will still stick with Salifert as my every day test kit, but it would give some piece of mind to have a more reliable kit on hand to check things with every once in a while. Then again, I probably just ought to start saving my money to replace my POS regulator/bubble counter and I wouldn't have to worry so much about test kits in the first place.