WHY

[Unitylover]

My salifert test kit i got is faulty, it claims it expires in 2026, but it is reading fresh saltwater at 12.5, and reads my tank, with three 20-38 water changes done last week, with IO salt (which mixes at 10 DKH), at 6 DKH. My calcium is at approx 420.

 

[Randy Holmes-Farley Verified Community Expert]

Why exactly do you think it is faulty? All of the things you mention can be true.

 

[Unitylover]

Why exactly do you think it is faulty? All of the things you mention can be true.

it was going at 6DKH for my tank, but arent alk and calcium linked? calcium is fine, so is it wrong?

 

[Unitylover]

just to see if it is faulty, ill do a WC today later on. If theres no change, then its prob broken, but if its higher, then you're right

 

[Chrisv.]

If you really think this is the case, try the following, which will be a little more controlled:

Mix up a fresh batch of salt water, let it sit for a day. Prepare a few samples of newly prepared water mixed with tank water and test at different mixing ratios. E.g. 100% new water, 0% tank water; 75% new water, 25% tank water; 50% new water, 50% tank water; 25% new water, 75% tank water; 0% new water, 100% tank water.

Doing this in isolation will tidy up a few variables, like water mixing, alkalinity consumption, etc.

Is there any chance that you're missing the end point on the titration, or not cleaning all of your testing supplies between tests (with rodi)? Those can both throw things off.

 

[Unitylover]

If you really think this is the case, try the following, which will be a little more controlled:

Mix up a fresh batch of salt water, let it sit for a day. Prepare a few samples of newly prepared water mixed with tank water and test at different mixing ratios. E.g. 100% new water, 0% tank water; 75% new water, 25% tank water; 50% new water, 50% tank water; 25% new water, 75% tank water; 0% new water, 100% tank water.

Doing this in isolation will tidy up a few variables, like water mixing, alkalinity consumption, etc.

Is there any chance that you're missing the end point on the titration, or not cleaning all of your testing supplies between tests (with rodi)? Those can both throw things off.

i dont use rodi. ill try this tho.

 

[EeyoreIsMySpiritAnimal]

Did you test freshly mixed saltwater at 1.025-1.026 salinity. With IO, you don't need to wait after mixing...
If so, what was the result?

 

[Unitylover]

I would test freshly mixed saltwater at 1.025-1.026 salinity. With IO, you don't need to wait after mixing...

Ik i did that. It got 12.5 -13

 

[EeyoreIsMySpiritAnimal]

Ik i did that. It got 12.5 -13

Then it seems like the test kit is accurate

 

[Unitylover]

Then it seems like the test kit is accurate

Ill do a WC today. If the alk doesnt change, Ill return it.

 

[EeyoreIsMySpiritAnimal]

i dont use rodi. ill try this tho.

Definitely rinse with distilled water then. You don't want the alk of your tap water to interfere with the results

 

[EeyoreIsMySpiritAnimal]

Ill do a WC today. If the alk doesnt change, Ill return it.

Why would you think the test kit is bad if it accurately measured new saltwater?

 

[Unitylover]

Why would you think the test kit is bad if it accurately measured new saltwater?

It measured my tank at a high 5 or 6, when i did 50% worth of WC last week.

 

[EeyoreIsMySpiritAnimal]

What is your system volume, and what coral is it stocked with?
You can have low alk with normal, even high, calcium.

 

[Unitylover]

What is your system volume, and what coral is it stocked with?
You can have low alk with normal, even high, calcium.

No corals yet, 10 gal

 

[EeyoreIsMySpiritAnimal]

It measured my tank at a high 5 or 6, when i did 50% worth of WC last week.

But new IO SW tested around what it is supposed to, so the kit seems to be ok.
Before returning it, I'd buy a different brand and compare the results with what you're getting with the Salifert.

 

[EeyoreIsMySpiritAnimal]

If your tank is new, with no coral, there's really no reason to even be testing alk, calcium, or magnesium yet.

 

[EeyoreIsMySpiritAnimal]

What's the salinity and temp of the aquarium water? (before a water change)

 

[Chrisv.]

I tested all when cycling a tank a while back and I was shocked by how quickly it was consumed. I too thought something must be up. How long did you wait between doing the WC and testing? I never came to a conclusion about where my alk was going. Could have been bacteria, algae, or even some sort of inorganic binding to my rocks or something.

If you did the WC, waited a week and then tested and got a low result, my bet is you're seeing something similar.

If it's that (whatever "that" is) it will level out soon.

 

[Unitylover]

What's the salinity and temp of the aquarium water? (before a water change)

The temp of the water is usally 1.025-1.026. The temp stands around 80, and im testing because I want corals soon, was planning this weekend. The only other brand i know and can trust and afford is API, which went bad and tested 2 alk. It was testing like 8-10 alk around the day before a WC. My tank is also 7-8 months old rn