Hanna checker readings way off?

[Mydoghasfleas]

I have been using the HI772 DKH checker for the past month, and have been consistently getting DKH 8.0. This is where I have been trying to keep it, and reflected that with my dosing. Today I ran out of reagent so went to go get more from LFS. New reagent showing DKH around 9.3. I got two bottles of the stuff, and tried both to rule out a bad bottle. Also changed batteries. Was my last bottle bad? Has anyone else encountered this? Can I rely on this checker, or should I go get something else, and what is recommended?

I have maybe 6 SPS frags, two LPS frags and a torch. Old checker reagent showed them going through about 0.1 DKH daily. Does this sound right?

thanks!

 

[Biologic]

I have been using the HI772 DKH checker for the past month, and have been consistently getting DKH 8.0. This is where I have been trying to keep it, and reflected that with my dosing. Today I ran out of reagent so went to go get more from LFS. New reagent showing DKH around 9.3. I got two bottles of the stuff, and tried both to rule out a bad bottle. Also changed batteries. Was my last bottle bad? Has anyone else encountered this? Can I rely on this checker, or should I go get something else, and what is recommended?

I have maybe 6 SPS frags, two LPS frags and a torch. Old checker reagent showed them going through about 0.1 DKH daily. Does this sound right?

thanks!

I like to keep a Salifert KH test on back up. A note though, you still perform it with the same methodology. The same every time. Same color change as your end point. This is a good thing to have on hand. So good consistent skill makes a consistent testing result.

Then you should always have a standard available. Such as salifert's standard you can test against using their instruments.

A good alternative would be to monthly test your saltwater for water changes at the salinity you always keep. Like 1.025 of the same brand at the same temperature, freshly mixed 24 hours old -- could be used as a standard.

With regards to your tests, at least you are consistently at a proper range for a reef. 8-9 dKH. Most importantly, you are consistently testing the same values. Repeatable instruments are most important. So what you decide what you want to do with your values is up to you.

Definitely get a manual test kit as a back up.

 

[Reef.]

People say you are not meant to use the last bit of reagent, think the bottle holds 30, you are meant to stop at 25, also it's important to keep the lid on the bottle, and replace the lid as soon as you can.

 

[guylaga]

Your not the first person to run into issues with the accuracy of the Alkalinity checker.

Like others have said once the reagent gets older and toward the bottom I start to trust the results less. I think its important that you have a back up red sea or salifert test to verify results every now and then.

But so long as I am getting the same or similar results from the Hanna checker I don't worry if I'm off by .5 or 1 dkh from the true level in the tank so long as the readings are stable and in the generally accepted range of 7 to 9 or 10.