Trouble Reading PH Color

[Jabooh1]

So I have been having trouble reading the ph color for a while. I can tell if it is in the orange range or the pick range but when it's the 7.5-7.7 it's hard for me to tell.

Is there a way to determine PH like the chlorine test where you look for it to go clear?

If not, what is a good recommended ph handheld tester? I don't mind spending the money to make sure I don't have a ph issue.

 

[Patrick_B]

It's a fairly frequent question. I've been considering a MyronL PT2. If you look on Taylor's (Taylor Technologies) website. They sell it for about $100. I know this brand well, and have heard good things about these from others in my industry. As a rule, inexpensive pH meters are problematic. Experience has taught me this as well.

 

[jrs_diesel]

You can try using 4 drops or even 6. It does not change the color of the sample, just the saturation of the color. I have a much easier time using 4 drops. You can also take a piece of thin white cardstock (business card can work), and cut a slot in the side of it so you can compare the sample to the scale one at a time. That makes it easier than looking at the sample and all 5 color scales at the same time.

 

[gilbee]

Patrick, about the PT2, is it impaired in the same way as the strips/drops in that it doesn't work well with high FC counts?

 

[Jabooh1]

LaMotte seems to have a lot of pocket ph testers as well.

 

[Patrick_B]

Patrick, about the PT2, is it impaired in the same way as the strips/drops in that it doesn't work well with high FC counts?

No, it wouldn't be. One thing though, is that they need care and attention to perform consistently. So you have to keep calibaration solutions on hand. No big deal, but it is critical. They also have to be stored with the tip where it never dries out. These like others will come with a storage cap to ensure that they stay wet. Stored for the off season, you'd want to get it out frequently (every couple of weeks at most) to make certain it doesn't get dry. The sensors on these can be replaced for about half the price of the whole unit however. I don't know about the Lamotte ones, but if I saw a picture, I might be able to tell you who makes it.

 

[duraleigh]

Let's go back to the first post.....if you can tell below 7.5 and above 7.7, then simply keep it in that 7.5 - 7.7range and your pH will always be perfect

 

[Jabooh1]

Yes, by process of elimination I could do that. However since I have had scale issues and I am concerned about the CSI over winter, I want the piece of mind that knowing the ph gives me.

 

[jblizzle]

So then shoot for slightly less than 7.5.

You can also get the acid / base demand reagents that let you change the color. I found this helpful to know what colors to look for.

- - - Updated - - -

EDIT: Really you will likely never need the base demand. I use the acid demand almost every time I test to see how many drops it takes to get to 7.5 or 7.2

 

[Jabooh1]

That was my original question. Using the acid demand, let's say my pool is 19k gal. and it takes 2 drops to get to 7.2. Other than checking with PoolMath is there a way to back calculate the starting ph?

 

[jblizzle]

There should be a table in the test kit manual (AT least I think it is in the K-1000 that comes with the TF-100). Or you can find it online I am sure.

 

[Jabooh1]

I have the table that is drops vs pool size and gives you MA required. What I was wanting to know is if there is a formula like:

ph(starting)=equation based on "number of drops", "after drops ph", & "pool size"

 

[jblizzle]

You can sort of figure that out using the table and PoolMath. Although I am not sure why it matters.

Just count drops to get to desired pH and use the table to tell you how much acid to add. I wrote down the amount of acid per drop for me ... it is around 1/4 gallon.

 

[Jabooh1]

That's what I am doing. Guess it's the best way. Just thought that if there was a formula I could keep it on my phone and it would be a little quicker.