KH test kit. TM and Salifert does not get same result

[MBruun]

I've always used Salifert KH test kit, but bougth a TM KH Alkalinity-Test (the cheap) since LFS was out of Salifert.
Making a few double check Salifert show more than 1 higher than TM.
Anybody have any expirience with the TM KH test kit ? Don't know which to trust now...

 

[MnFish1]

I've always used Salifert KH test kit, but bougth a TM KH Alkalinity-Test (the cheap) since LFS was out of Salifert.
Making a few double check Salifert show more than 1 higher than TM.
Anybody have any expirience with the TM KH test kit ? Don't know which to trust now...

The only way to be 'sure' is to get a third test done. Hopefully this will help determine which one is correct. I assume you mean tropic Marin tests?

 

[MBruun]

I also "feared" that would be the option - to use a third test kit ;-)
Yes I mean Tropic Marin

 

[homer1475]

Have always trusted salifert, even over the hanna egg.

I would trust the salifert kit.

 

[Koigula]

I just do weekly 20% water changes instead of relying on lots of additives and accessories. It seems obvious but hobby is overly complicated. I use Hanna checker but very critical to use bottle up quick and refrigerate once open otherwise test results drops and mold gooey stuff eats reagent.

For test kits, I use following after decades in hobby.

Salinity - Tropic Marin Density stick to 1.026 sg
Alkalinity - Hanna ppm KH Checker - refrigerated open reagent bottles or use another kit
Calcium - Aquaforest
Magnesium - Aquaforest
Potassium - Salifert
Phosphate - Hanna ULR ppm Checker
Nitrate - Hanna HR Checker

I am not convinced +/-5% matters on tests much other than salinity and alkalinity. It would be basic high school chemistry to run 250 flask with 200 ml sample with indicator and 0.1 N acid reagent to reduce error in alkalinity testing. I am always amazed coral farms buy hobby kits if livelihood depends on it.

 

[Randy Holmes-Farley Verified Community Expert]

I just do weekly 20% water changes instead of relying on lots of additives and accessories. It seems obvious but hobby is overly complicated.

Well, it seems obvious to me that 20% weekly water changes cannot possibly hope to maintain alkalinity on any tank except with very low demand for alkalinity, and then only if you use a salt mix with alk far higher than your target in the tank. Simple math shows that.

Dosing is also ALWAYS cheaper than water changes to maintain calcium and alk, unless you are already doing those same changes for other reasons.

 

[MBruun]

To determine which of my test kit to trust, I would like to make a liquid with a known alkalinity. But how ?
Using TM pro reef salt I cannot find the exact amont of salt to mix to get a specific KH value .
Like xx gram salt in 1 liter ro water = yy dKH

 

[homer1475]

Easiest way to test the test kit, is with a standard.

Fauna marin makes a standard. I realize you are in Denmark and cannot use BRS, but this will give you an idea of what it is:

Saltwater Multi Reference Solution

The only reference solution based on a saltwater matrix that includes 8 of the most popular parameters for saltwater aquariums in a single solution. Fauna Marin’s Multi-Reference Solution is used to check your home water test kits for accuracy. Using your water test kits at home, you can measure...

www.bulkreefsupply.com

 

[rtparty]

This may help or confuse you more lol

Alkalinity titration endpoint pH & Salifert endpoint color

TL;DR: The endpoint pH is 4.41, and the endpoint color is that "lavender" color I've been telling people about. Over the years, there have been many threads on R2R and other forums debating a couple of basic details relevant to testing for alkalinity in reef aquaria. One of the most...

www.reef2reef.com

 

[MBruun]

Super now it actually makes a little sense.
When aiming for the hot pink (thought was the colour for the endpoint) on Salifert, I then read a higher KH value than what the test kit actually show.
Might be that TM and Salifert is not that far apart as I thought, I just have to learn how to read the Salifert data lol

New endpoint reading - funny how colours change on pictures, but the colour actually match the endpoint colour on the screen

 

[Koigula]

Well, it seems obvious to me that 20% weekly water changes cannot possibly hope to maintain alkalinity on any tank except with very low demand for alkalinity, and then only if you use a salt mix with alk far higher than your target in the tank. Simple math shows that.

Dosing is also ALWAYS cheaper than water changes to maintain calcium and alk, unless you are already doing those same changes for other reasons.

Well not quite so literally as to not add alkalinity! I add plenty of kalk metered carefully at night and make up with bit of soda ash twice a week to stay on target 155 ppm . 50cc BRS Soda Ash jug raises my system 5 ppm alkalinity.

I do 20% weekly IO reef crystals water changes on smaller system. I do this instead of gadgets like roller mats, denitrators, ozonizers. I am having long term success with simple and enjoy hobby again. T5, Kalk, Barebottom siphoning detritus weekly, but never leave it too clean!

 

[doubleshot00]

I've probably got 5 different KH test kits and they are all off from each other. Why I just use the hanna alk and keep my alk at 8.5 to have wiggle room incase there are testing errors. Same with cal and mag test kits.

 

[Koigula]

I've probably got 5 different KH test kits and they are all off from each other. Why I just use the hanna alk and keep my alk at 8.5 to have wiggle room incase there are testing errors. Same with cal and mag test kits.

I went same route. It is good enough. I found tip to refrigerate reagent to be be helpful.

I would see if new version of Hanna Magnesium works but found I really only need to test once a month.

 

[doubleshot00]

I went same route. It is good enough. I found tip to refrigerate reagent to be be helpful.

I would see if new version of Hanna Magnesium works but found I really only need to test once a month.

Same

I found by using the syringe to puncture a hole in the top to keep the light and air out it works great for me. I got enough crap in the fridge my with doesn't like another. Sometime worms are in there.

 

[homer1475]

I have found the mag kit from hanna still reads consistently high. Even with the new powdered reagents. Its very consistent, but high none the less. Not that it really matters if mag is 1300 or 1350. As long as it is "in range" I'm good with it.

I wish I had never bought it with the amount I actually test MAG. Pretty sure my reagents will expire before I use them all.

 

[Koigula]

Same

I found by using the syringe to puncture a hole in the top to keep the light and air out it works great for me. I got enough crap in the fridge my with doesn't like another. Sometime worms are in there.

I use an old college beer fridge for basement. She is low key and tolerant but fish food was in refridge was a trigger.