Test kits have me going crazy!

[tpack17]

I have a 150g tank with a 40g and 60g sump.Mixed reef, have about 11 SPS frags and 20 LPS varieties. Nothing huge but med size hammer, torch and BTA.
I have been using salifert alk test and just recently bought a new hanna alk tester. Now here is the problems. Usually a few days after a water change I would get 7.8ish on salifert. It was going down to 7.3 after a week. Figured I would need to start dosing a little so I picked up dosers.Not in use yet.
First test with hanna was 7.3. Right on. Every test after has been 8.5 ish. Tip on, tip off.Vials rinsed
in rodi after.
So I am really confused. Before WC today I just tested my tank and fresh fritz salt at 35p.
Salifert: tank 6.9 Fresh Fritz 8.7
Hanna: tank 8.5 Fresh Fritz 10.4

I will also mention I have 2 salifert alk tests since this craziness. No difference there.

Took sample to LFS and they used salifert and came in at approx where I am with my salifert. What gives here? Any thoughts on what you would do? I am leaning salifert at this point.

 

[KJ]

Salifert for NO3 Ca Mg Alk
Hanna for PO4

 

[KJ]

I am leaning salifert at this point.

Good choice.

 

[tpack17]

Is this typical with hanna for alk?Just wondering.

 

[Angrywalnut]

My Hanna Alk is typically within .3 of Red sea Pro test kit. I have not checked it against another kit.

 

[JimWelsh]

Good choice.

+1

 

[PatW]

Your two tests, Salifert and Hanna, say the the alk in your tank is 1.8 or 1.7units lower then the salt mix. It looks like agreement to me. The problem is the calibration of the results. You could decide that your salt mix is a standard and use that as a reference. I suppose that you could mix up your known reference solution on your own. It seems to me that the real danger is a low enough ALK to cause a tank crash. So you could use the higher value to play it safe. But if you are thinking of running an ultra low nutrient level, you want to run about 8. So if that is your desire, you are kind of stuck. Generally, it is better to run a stable ALK than any particular level within reason. If your tests give consistent results, either will work.

 

[XNavyDiver]

Is this typical with hanna for alk?Just wondering.

Not for me. I use Hanna and Fritz also. I measure 8.5 to 8.6 when I make a fresh batch for a water change everytime.

 

[XNavyDiver]

You can see if your checker is reading within tolerances by getting their alk standards cuvettes.

 

[tpack17]

You can see if your checker is reading within tolerances by getting their alk standards cuvettes.

That is my plan. It seems that it is clear it is off based on my testing. Ill try that next.TY
Pat, my plan is to stay at 8. It just was confusing me with the hanna. Still stumped why first use was on money then bam,high.

 

[cracker]

My Hanna is also .2/ .3 lower than the redsea kit. Close enough for me.

 

[madweazl]

Every time I measure with Hanna and Salifert they are .3 different in regard to alkalinity. No clue which one is "correct" but they're consistent. Not sure why your delta is so much larger.

 

[rkpetersen]

Over the last 6 months, I've tried out most of the major hobbyist test kits against identical samples sent to Triton, ICP-Analysis, ATI, & AWT. So much testing. These are the tests I prefer, based on accuracy and reproducibility in my hands. (Less optimal kits, but still useful for confirmation of primary results, are in parentheses.) Some of these might not be ideal for others, e.g. the Hanna calcium test requires precise technique to get consistent results.

Alkalinity - Hanna (Elos, Giesemann)
Calcium - Hanna (Salifert, Giesemann, Aquaforest)
Magnesium - Salifert (Giesemann)
Potassium - Salifert
Nitrate - (Red Sea, Nyos, Giesemann)
Phosphorus - Hanna (Hanna phosphate, Elos phosphate)
Iron - (Hanna)
Iodine - No good test
Strontium - No good test
Oxygen - Lamotte

 

[Berlibee]

This + 100

Salifert for NO3 Ca Mg Alk
Hanna for PO4

 

[madweazl]

I hate bottle B of the Salifert calcium kits; I screw up getting eight even drops pretty often. Last week I bought the Red Sea Pro kit for calcium and it was considerably more user friendly. Results between it and Salifert were < 5ppm so it is my go to kit for calcium now.

 

[Berlibee]

I've tested twice Salifert test kits with Triton and ATI Lab water test each time they were absolutely identical to my readings at home.

 

[tpack17]

I've tested twice Salifert test kits with Triton and ATI Lab water test each time they were absolutely identical to my readings at home.

Good to know. I have just started dosing alk so I need consistency.

 

[tpack17]

Just a follow up guys. It was the reagent for the Hanna that was bad. Tested Hanna and was okay. Bought new bottle of reagent and it is same as salifert now.