Need Help Reading pH with TF Pro

[MyBikeIsAwesome]

Hi, I’ve been using the TF Pro test kit, but can’t seem to figure out how to read the pH. I try to hold it near a light source and put a white paper a few inches behind the comparator, but I’m rarely able to compare the colors with confidence. This is what I’m trying to read tonight. I’m guessing it’s somewhere between 7.5 and 8.2 but not sure.

Any tips for reading it? If I capture an image and extract the RGB value does looking at one or a combination of the values help?

 

[proavia]

Try using 4 drops instead of 5.
I find this works better for my eyes.

 

[pjt]

A consistent background is key. To get a consistent backlit background, hold the block in front of your computer monitor with a blank white screen displayed (I use Google's homepage). Also, try holding the block sideways or upside down. Sometimes that helps distinguish colors better. I also use two old hotel keycards to mask off areas and narrow down my decision.

 

[SoDel]

I don”t have “the answer” for your question but I can say what works for me. First off, keep in mind that pH can move around a bit in response to many things that can end up or happen in your pool over the course of a swimming day — what I’m getting at is don’t sweat an exact pH value; just make sure you can get to an “about” as of the moment you sample it. If I understand what’s taught here correctly, you want to keep your pH in the 7’s. Mine is almost always in the high 7’s and I try to avoid letting it creep up into the 8’s. High 7’s will look “reddish” just like 8’s but it will still have that little hint of an ”orangish” cast in it if you look at it in natural light. When it’s reddish with no hint of orangish, time to add acid. Hope that helps.

P.S. to my eyes, your sample definitely has plenty of orangish. I’d go with 7.5.