old news new #'s

[tuberider]

Went crazy with the Alk. test kits today. Normally I'm sick of drops in vials at the end of the day, today I was motivated here you go...


Alk in my tank according to our precious test kits

API-> 9dKH (brand new)
Hagen-> 10dKH
SeaChem-> 6.7dKH
Salifert #1 -> 9dKH (one step type with orange/red tritrant)
Salifert #2 -> 7.4dKH (two step less than 6 mos. old)
Salifert #3 -> 6.7dKH (about one year old lives in my apt. with no light and stable temp, two step)


Here's the kicker, chem people help me out->

One step Alk test (Salifert w/ Salifert reference solution)

Salifert #1 -> 5.8dKH reference solution is supposed to be 7.0dKH


Strange huh? I kept hearing Flava Flav "You can't trust it" playing in the back of my mind.

 

[Gomer]

These tests were all CE certified (Close Enough)

 

[fishnfst]

I had a salifert alk test kit that was consistently off 1.5dkh.. Salifert sent me a new test kit with reference solution.... check out the salifert forum on RC... I haven't looked in awhile but that was about 6-7 months ago when they sent it to me...

 

[tuberider]

What's off? I dunno, what's reading right? I have no idea anymore

 

[sfsuphysics]

Well as long as they are all constantly off the same amount in the right direction every time you test you're golden! It's not about low alk (at those levels they're fine IMO regardless of which one is the true number ) but as long as you don't fluctuate you're golden.

 

[tuberider]

Did some ore tests this morning using the salifert reference solution and am now ready to give up testing Alk

Salifert #1 gave me 9dKH from my tank, & 5.8dKH using the 7.0 reference solution (repeated twice)

API gave me 9dKH from my tank, and 7dKH from the reference solution

Hagen gave 10dKH from my tank, and 8dKH from reference solution

I think my tank is around 9dKH, right where I like it. I think ???

 

[tuberider]

Sea chem with reference solution 5.4 dKH

 

[sfsuphysics]

Aquarium pharmaceutical for the win!

 

[alve]

Interesting. I have an API and an Elos test kit and both of them show my tank is 8dkh.

Looking at your results API is the only one that comes up with the correct reading for the reference solution.

And the winner is..... API, I guess Isn't there another post somewhere on here about API being off about 2dkh?

 

[tuberider]

Yeah, that was Norman, I trust him more than me ;D IIRC at higher values the #'s are skewed with API. When I was testing though I was thinking to myself no sh*t the cheap one wins? It can't be true, I do use API on my customers tanks, and couple of those tanks do amazingly well so who knows.

 

[seminolecpa]

If you want to use my Elos kit to add to your data let me know.

 

[seminolecpa]

BTW did you see this thread? Interesting. Not sure I would mess with it but interesting.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1370029

 

[bluenassarius]

hey bryan,

whats your #. i lost it from yesterday. or call me at 9168020105 por favor

 

[tuberider]

[quote author=seminolecpa link=topic=3559.msg40727#msg40727 date=1208283713]
BTW did you see this thread? Interesting. Not sure I would mess with it but interesting.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1370029
[/quote]Haven't seen it, I'll look into it, AFA Elos I'm outta reference solution so my little tests are over. I'm no chemist, I'm just confused as to how the reference solution can test different with two kits, yet those very same kits can produce the same results with my tank water, again cue Flava Flav.

 

[Mr. Ugly]

[quote author=seminolecpa link=topic=3559.msg40727#msg40727 date=1208283713]
BTW did you see this thread? Interesting. Not sure I would mess with it but interesting.

http://www.reefcentral.com/forums/showthread.php?s=&threadid=1370029
[/quote]

I've done the pH meter titration method a few times before. More involved than the typical hobby test. Works well, but probably not something you want to set up and maintain for everyday use.

 

[Mr. Ugly]

[quote author=tuberider link=topic=3559.msg40737#msg40737 date=1208299687]I'm just confused as to how the reference solution can test different with two kits, yet those very same kits can produce the same results with my tank water, again cue Flava Flav.[/quote]

Can't think of the mechanism for that right now, but it's probably relates to interference or lack of it from from others ions not being tested for. Similar to how some Ca tests are affected by Mg, or some alk kits are affected by borate.

 

[Gomer]

Similar to how some Ca tests are affected by Mg,

But that is why we add NaOH to precipitate out Mg(OH)2..hmm..since you are titrating with EDTA, I guess you could do the test twice with and without the base and get Mg+Ca and Ca :-D