ACO Test Strips - How hard is my water?

[TravisN]

I've been using the ACO test strips for a while, and I've always kinda ignored the hardness reading because this color doesn't look like any of the colors on the side of the bottle to me. I've never tested it any other way, and my house have other symptoms of hard water, but I've always wondered. Might be hard to see in the photo, but what do others think? 

[HelplessNewbie]

My middle aged eyes tell me that GH is past 300. Hope that helps.

[Galabar]

From what I've seen here (and what I see when I use ACO test strips), anything purple (light or dark) is 300+.

 

[nabokovfan87]

On 7/28/2023 at 2:54 PM, TravisN said:

Might be hard to see in the photo, but what do others think? 

I would re-test using the method in this video.

Try to use the plastic color scale that comes with the strips to take your photo.  Having the strip side by side with the scale helps a ton.
 

 

[Tanked]

I have always gone with 300+ for similar coloration. 

A newly purchased liquid test kit indicates a lower value. In my case  the numbers are between 232-250 ppm.  A single drop of water will change the reading.  Lacking a more detailed color scale, my thought now is that as the GH scale changes from blue-purple-violet.  A lighter shade of violet is something less than 300.  Close enough for non-laboratory conditions.

[TravisN]

Thanks for the input, everybody. I retested to day using the towel method above and got more or less the same results. Just for a point of comparison, I dipped a test strip into a bottle of store brand "natural spring water" and got a similarly not-on-the-chart purple color. 

The results from the bottled water are attached. 

 

 

[Tanked]

"Natural spring water" can come from a variety of sources.  The hardness could be that high.   Just for fun, I  just tested some Aquafina water and Ice Mountain "Natural spring water".  The Aquafina is said to be RO water and as expected, produced zeros across the strip.  The "Natural spring water" produced a color that would be between the 100 and 200 mark on the Nitrate chart.  Drop tests indicated 214. 

In the end, I like the idea of being able to test all of my aquariums in under 10 minutes using the strips.