inaccurate alk test

[Bonsai_Reef]

ok how are your accuracy on the alk test using the hydros x10 and iv?

ive replaced the ph probe with a milwaukee, followed the video instructions, mixed the reagent using a scale 1 part solution and 4 parts rodi water.
re-calibrated the dosers using a graduated cylinder, bought a bigger one to callibrate the fill doser as well. after all that im getting readings 2+dkh over my hanna test and even bigger gap when compared to the salifert test kit.

 

[JeffB418]

Highly suggest using a scale to calibrate both the sample and reagent pumps. See here the details on how to do so and account for density for salt water: iV/X10 Setup Suggestions

Other things to check:
- make sure the iV is no more than 3 ft away from the X10, closer the better
- also try to keep the iV around the similar height to the X10 if possible, not required
- Make sure the dip tubes are as such:


- Make sure the pH probe is between 1/4" and 3/4" from the beaker bottom
- Try to start with the Trimetric pH 4.5 mode for alk detection first if you arent using that method

 

[JeffB418]

Also check if your reagent is mixed correctly:
Reagent Testing:
- There is a way to use Salifert Alk testing kit to verify your diluted reagent.
- First test your sample water using the salifert kit as directed, note the ALK value produced by the test.
- Second, re-test again using fresh sample water but this time instead of using the salifert liquid reagent, use your mixed iV reagent in the syringe. Run the test the same as before, ended at the same color conversion. Then note how much reagent from the syringe was USED, IE if the syringe has 0.4mL left, you USED 0.6ml. Take the USED value and calculate dKH using this equation: dKH = iV Reagent Used (mL) x 250 x 0.056.
- Compare the ALK value generated by the standard salifert test and the second test with iV reagent. If your reagent is mixed correctly, these should be close. If your iV test dKH is really high or low compared to the salifert baseline, your reagent is mixed wrong.

 

[Adamc1303]

Ok the reagent is bad! The Salifert test came in at 8.9 which matches my Hanna checker and close the 8.5 that I aim for. I expected all to be a little higher as I did a 3 day lights out and fingers crossed with a lot of trial and error may have finally beat Dinos! I am happy it’s just reagent as it seems like an easy fix. Where do I get reagent? The last batch was directly from Coralvue and came premixed. What other options do I have?

 

[Adamc1303]

Sorry replied to the wrong thread