Trident error range for Calcium testing is +/-50ppm??????

[jkobel]

I have a new Trident (2 months old) and calibrated per instructions. My Calcium readings are all over the place to the point where i had to turn off my dosers in order to get a clear idea of whats actually going on in the tank. What I expected was to see a somewhat steady decrease in Ca over several days as it was consumed, although there is a margin of error with the unit so there could be variation.

What I found is the attached graph with Ca readings continually going up while nothing has been dosed.

I contacted Trident support and their answer was this-

"The error range of the TRIDENT for Calcium testing is Plus or minus 50 PPM, so if you are seeing a "shift" that is less than that 100PPM window, I believe what you are seeing is natural variation in the Trident testing, and not an actual shift of your tank chemistry, since those readings that are 25ppm off, could technically be the same value, because of the error range."

The stated range is +/-15ppm for Ca according to the web site and literature. Am I misunderstanding somethgin here? Since the target range of Ca is only slightly higher than 400, an error range of 100ppm is a significant variance.

I pointed that out to support and havent heard back but asking this community of your experience. Unfortunately the Neptune forums dont seem to be very well used as most of the recent posts are weeks+ old.

any insight is appreciated.

 

[Reefer Matt]

What’s your salinity looking like? It looks like the tank isn’t getting topped off or getting dosed too much.

 

[jkobel]

1.025 and stable.

Thats the first thing I thought as well but water levels are stable and ATO is spot on

 

[Reefer Matt]

1.025 and stable.

Thats the first thing I thought as well but water levels are stable and ATO is spot on

Ok. What are you dosing for alk, Ca, and Mg?

 

[jkobel]

BRS 2 part, mixed per instructions. Currently, dosers are turned off so this reading is showing an increase that shouldnt exist.

 

[jkobel]

Something interesting to note - I think I'm watching your video on calibrating the Trident right now and I dont recall the instructions telling me to "prime" the Trident with the calibration fluid. Its possible i did that but it doesnt ring a bell.

Thats not going to change whats happening now with Ca but it would explain the variance i see with Alk and Mag from my Hanna

 

[Borat]

This still better than a +/- 400ppm

 

[Reefer Matt]

Something interesting to note - I think I'm watching your video on calibrating the Trident right now and I dont recall the instructions telling me to "prime" the Trident with the calibration fluid. Its possible i did that but it doesnt ring a bell.

Thats not going to change whats happening now with Ca but it would explain the variance i see with Alk and Mag from my Hanna

It doesn’t look too bad though. You may have to tweak your dosage. It’s not always a 50/50 on alk and Ca. Do you know what your daily consumption rate is? And is alk going down as Ca is going up?

 

[Js.Aqua.Project]

Not that this will be the most useful tidbit but I've had a Trident for almost 4 years now and here are my observations over that time:

• Temperature fluctuations impact testing results
  • I've noticed that as the house gets colder my readings (especially Alk) will have wider swings
    • I live in Central Florida so during our version of winter we usually will just turn off the A/C and open the windows - fresh air also gets a bonus pH boost sometimes (unless it's going to be down in the 20s or 30s, the tank's heaters still keep the tank warm enough)
• Variance in testing changes based on intake hose location
  • When I put my intake hose closer to the return pump vs keeping it in the first chamber of my sump impacted testing ranges, have generally found more consistent test results with the hose in the first chamber
    • Not sure the reason for this, just an observation, my only thought is that because of the larger mass of water in one location that maybe that makes it more consistent verse the turn over of the return chamber??? (Brain says shouldn't matter as in theory everything should be homogenous and not matter where the water sample is pulled from - hence I have no clue if this is just an issue of correlation not causation)
      • only "logical" answer for me here is potential of air is higher for me in the return chamber
• When reagents get low (especially Alk) readings can start to vary
  • Just be on top of changing reagents, yes in theory there is more in the bottle that required for the number of tests but maybe due to exposure/outside influence on the reagent
• Calibrate, calibrate, calibrate
  • While I have not personally done this, I remember seeing a post of someone else using a known reference standard and calibrating their Trident every 2 weeks
  • Having that calibration standard at close to the same temperature as your tank does seem to have some impact on accuracy but not sure if significant enough to add to calibration procedure like having it at the same height as your water in take