Neptune Trident Alk readings maybe off, a tale of 3 different test kits.

[TheDragonsReef]

Protip: use whatever test kit you trust the most to test Alk, ca, Mg of your tank. Then run a calibration using your tank water and enter the reading from the test kits.

It might not give you the true value, but it will have all your test methods' reading line up. This trick saved my sanity. Also that's the reason I recommend keeping Alk target at 9. So if the test are off by 1, it will still be between 8 and 10. Any number within it is perfectly fine. Stability is more important. Trident reading does tend to be pretty consistent, so everything works out well.

I do this too, that way when i manually test and the result is different i know something is up.

 

[lefkonj]

Funny I use my trident to view major changes and track them in my tank. If I just mix a fresh batch of ALK I know the readings will be off for a few days but then stabilize. Same with changes to the trident chems.

 

[PatW]

This is a precision vs accuracy issue. Think of a rifle range. The grouping of the shots is precision. Accuracy is actually getting the right answer. If you have a really precise measure and know which way it tends to be off (by using a standard), then all you need is to correct the test result to get an accurate result. But if you have a really accurate test which is not very precise, you will have to take a pot load of measures and average them to get a precise and accurate result.

I measure ALK daily using Salifert, Hanna and Red Sea Pro. In my results, Salifert reads the highest (like 9.3), Hanna reads next (like 8.2) and Red Sea reads about (7.8). So which one is “Right”. I don’t know. It is the right ball park. I look for a trend day to day and try to keep a constant level.

I could make an Alkalinity standard to see what the REAL value is. Randy has instructions on how to do it. But I would have to buy a scale and I have not bothered. Sometimes I think of the days when I had access to a decent laboratory and had volumetric flasks, pipettes, centrifuges, photospectrometers, analytical balances, fume hoods, ahhh happy days.

 

[trmiv]

FWIW I did make the Alk standard that Randy posted about because I was getting the same thing where my Trident tests differently than my Hanna and Salifert kits. The standard has an alk of 7.0 and after calibration my Trident tested it at 7.01. I feel pretty good about trusting the Trident for alk after that.

I did have a lot of alk consistency issues with my Trident for awhile until support walked me through cleaning the cuvette. It was fine and then just started suddenly giving me readings all over the place. I guess it finally got dirty enough to impact the consistency. When we opened it go my cuvette was crazy dirty with black gunk. The cleaning made a huge difference.

 

[Cjeippert]

My hanna alk checker has always read higher than trident for alk. For example when trident reads 7.6 the Hanna will be 7.8 or up to 8.2 depending on which Hanna bottle of reagent I draw from.

Magnesium: salifert test 1450, ICP triton 1500, Trident 1325.

yes I recalibrate but magnesium often reads way to low on trident.

my calcium is typically spot on, with trident and salifert and ICP. However I have had problems with trident reading higher and higher calcium like 435 to 500 in 2 days. I panicked and shut off calcium dosing and trident showed calcium at continually high levels. I tested with salifert and bam calcium 390. That tells me calcium never sky rocketed. So I cleaned the trident sample in line and primed everything, then bam calcium matched both trident and salifert. Trident gets air bubbles and sucks in gunk which throws things off.

I feel many tridents act differently and when you learn through the many problems you encounter and understand the repeatable discrepancies you sort of know where you are at.

 

[Cjeippert]

Another nightmare I had was to allow Trident to determine how much alk and calcium my system needed. It was constantly thinking it needed more of each because it would dose at the exact same time. Weeks of uping both soda ash and CaCl turned into a precipitation nightmare. Ended up with a sand box for return chamber, a return pump that seized up every couple of days. And a nice coating of precipitate inside plumbing.

I prefer to dose alk and calcium during different periods and when I stick to the same amount each day the system stays stabilized as opposed to algorithms making the dosing amount go up and down.

also high flow powerheads in return chamber helped the precipitation issue. This was a very stressful time and a good lesson I learned with automation. I had to stop dosing for a couple days to see the drastic drop to identify true alkalinity needs and go from there with calculated dosing amounts. Surprised my corals handled that big dip, I thought for sure all acros would die over next few months. , but everything ended up fine.

 

[ROX'S REEF]

@PedroYoung try this