Trident - always seems a bit off?

[squarereefer]

I have owned a Trident for several months now and love the idea. I also realize there is some margin of error in all hobby grade testing. However, I am driving myself in sane with the Trident because my CA and All always seem to be low. For example, ALK currently reading 7.88, Calcium 398. Cross checking a few times with a Hannah meter for Ak and Salifert for Calcium shows 8.1 all and 450 calcium. Magnesium on the trident always seems to be pretty close to my Salifert test.

The trident is calibrated to my Hannah/salifert test using the tank water method. If I re-calibrate, it will seem ok fora. day or two then start wandering off again. Does this seem like too big of a difference given the accepted margin of error on tests? I'd Leo to one day trust it enough to drive my DOS pumps, but with a 50 point difference in calcium I don't see that happening.

 

[BigKid4788]

Have you ever tested the calibration fluid for the trident w salifert to ensure accuracy? Do you recalibrate after you change reagents w the calibration fluid?
I’ve let mine dose for over 2 yrs.
Alk difference of .3 is nothing to worry about.

 

[Syntax1235]

I view the value of a trident is with keeping track of trends and not necessarily a specific number.

I know the trident is fairly close (at least according to my salifert tests); however, being able to see an increase or decrease in one of the three values helps me to make adjustments to dosing.

 

[vetteguy53081]

I have owned a Trident for several months now and love the idea. I also realize there is some margin of error in all hobby grade testing. However, I am driving myself in sane with the Trident because my CA and All always seem to be low. For example, ALK currently reading 7.88, Calcium 398. Cross checking a few times with a Hannah meter for Ak and Salifert for Calcium shows 8.1 all and 450 calcium. Magnesium on the trident always seems to be pretty close to my Salifert test.

The trident is calibrated to my Hannah/salifert test using the tank water method. If I re-calibrate, it will seem ok fora. day or two then start wandering off again. Does this seem like too big of a difference given the accepted margin of error on tests? I'd Leo to one day trust it enough to drive my DOS pumps, but with a 50 point difference in calcium I don't see that happening.

It generally is. Instead of calibration fluid, do manual tests for alk-Ca-mag and use those numbers

 

[squarereefer]

Thanks everyone for the replies - perhaps I didn't explain well enough that I've never used the calibration fluid. I use the "tank water method" where I test with my Hanna's / Salifert and then calibrate based on those numbers. Once I calibrate, it seems accurate for a day or two and then starts reading progressively lower. I most recently calibrated about 10 days ago after changing reagent A and now I am back to being a little off. It's weird that Mag seems to test accurately, it's the 50 pt calcium I am more worried about.

 

[gbroadbridge]

Thanks everyone for the replies - perhaps I didn't explain well enough that I've never used the calibration fluid. I use the "tank water method" where I test with my Hanna's / Salifert and then calibrate based on those numbers. Once I calibrate, it seems accurate for a day or two and then starts reading progressively lower. I most recently calibrated about 10 days ago after changing reagent A and now I am back to being a little off. It's weird that Mag seems to test accurately, it's the 50 pt calcium I am more worried about.

I can appreciate the frustration, but chasing numbers drives people nuts.

Tank water is not a method I would use to calibrate any measurement instrument as the composition of tank water can and will vary during the day. Use a calibration fluid and if the device is then within roughly 50ppm of another measurement device call it quits.

Keep Ca around 425 and then either instrument is likely correct.

 

[squarereefer]

Note taken - time for me to relax and stop stressing!

 

[Waters]

My Trident was actually closer to correct numbers that I had originally thought. Twice I have checked numbers against ICP testing (over a 8 month span) and both times the Trident was closer to the ICP tests than any of my manual test kits, which previously I thought were more accurate. Maybe get an ICP test to verify how inaccurate your trident actually is?

 

[Cnidaria]

I have owned a Trident for several months now and love the idea. I also realize there is some margin of error in all hobby grade testing. However, I am driving myself in sane with the Trident because my CA and All always seem to be low. For example, ALK currently reading 7.88, Calcium 398. Cross checking a few times with a Hannah meter for Ak and Salifert for Calcium shows 8.1 all and 450 calcium. Magnesium on the trident always seems to be pretty close to my Salifert test.

The trident is calibrated to my Hannah/salifert test using the tank water method. If I re-calibrate, it will seem ok fora. day or two then start wandering off again. Does this seem like too big of a difference given the accepted margin of error on tests? I'd Leo to one day trust it enough to drive my DOS pumps, but with a 50 point difference in calcium I don't see that happening.

I agree with BigKid I use the calibration fluid and check my test kits against it. Most of the time I find I have a bad test kit or I need to calibrate the Trident with the calibration fluid provided.