Tetra 6 in 1 strips and a blue result

[Inkylee]

I got a blue reading in the alkalinity reading and there is no blue on the chart. Does anyone know where on the spectrum the blue would land? My water ph is just between neutral and alkaline closer to neutral. 

Any help would be appreciated, so, thanks in advance.

[daggaz]

What are you measuring again? Alkalinity/acidity is measured by pH, but you say you measure your pH and get it just a smidge over neutral.  That's normal and fine.  So are you getting a blue color (that doesnt exist) on the pH section of the Tetra 6 in 1?   Sounds like the strip is defective, or you contaminated it somehow.   

For test strips, you want to leave them submersed until they stop changing color, and this can take a good ten minutes if you have a lot of buffer in the solution (KH).  Then you should read them immediately after taking them out of the water.  Some strips will start reacting with air after being immersed and give you erroneous results (often moving towards very high pH).  

[Rube_Goldfish]

On 6/21/2024 at 12:49 AM, daggaz said:

For test strips, you want to leave them submersed until they stop changing color, and this can take a good ten minutes if you have a lot of buffer in the solution (KH).  Then you should read them immediately after taking them out of the water.  Some strips will start reacting with air after being immersed and give you erroneous results (often moving towards very high pH).

I've never used Tetra test strips, but I use Sera test strips and the instructions on that product are very different. Sera wants you to dip the strip for one second, then set it somewhere flat for one minute, then read it.

[daggaz]

I dont know, thats the standard for pH strips in the lab, really.  Buffers slow down the availability of H+ ions and that can give falsely high readings if you dont give the strips time to react.  They all work on chemical reactivity principles so the physics there should be the same.  

I'd recommend getting a pH meter tho if it was anything but the standard aquarium tank.  Strips are just generally bad when it comes to precision and accuracy.