is sali STILL having realiability issues?

Acroholic · Nov 5, 2009

gregr said:
Not exactly what I expected. The Sera kit gives 7dKH and the Salifert 7.5 on newly mixed saltwater. On my tank water Sera read 9 and Salifert 11.5. Did both tests two times on tank water and new saltwater. Results were the same on all four tests.

Have you tested against the reference solution Salifert includes in the Alk test kit?

I'll test my Salifert vs my reference and report back.
Dave

Acroholic · Nov 5, 2009

I just tested my Salifert alkalinity test kit against the reference solution they provide in the kit itself. There is a statement at the top : "This is a version introduced, on basis of received feedback, in February/March 2008."

The reference solution is 7.3 dKH +/- 0.3. I got a color change when the reading on the 1 ml syringe was .54 ml, which corresponds to 7.4 dKH.

So at least my test kit seems to be accurate.

Anyone else test vs the reference solution?

Ike · Nov 6, 2009

Be weary of reference solutions that come with test kits. Not saying this for Salifert in particular but in regards to all reference solutions provided with any test kit... One example is the Seachem calcium test kits. Not sure if they're still as bad as they used to be, but about the only thing they test accurately was the refenece solution, everything else was off by 50-100ppm.

And yes, I have tested vs. the reference solution with all 3 of my Salifert alkalinity kits, one of them is pretty close (the old expired one), another is a little high (this is the "fixed" version of the kit), and the other is bewteen 2.5 and 3 dKH too high.

Acroholic · Nov 7, 2009

OK...but how can a chemical test kit be accurate on a reference solution check, but be bad otherwise?

If the Alk test tests accurate with the reference solution, then it should test acurately at other KH values, right?

Is there something shady is going on, are you saying?

Ike · Nov 7, 2009

Acroholic said:
OK...but how can a chemical test kit be accurate on a reference solution check, but be bad otherwise?

If the Alk test tests accurate with the reference solution, then it should test acurately at other KH values, right?

Is there something shady is going on, are you saying?

Call it what you will... But, it seems it's far easier to design a reference solution to be read where you want it to than it is to make a test kit that is accurate.