What's my Cl and pH - color test included.

another one

Well-known member
Jul 1, 2010
49
Seattle area, WA
Hopefully a decent picture, white background, sun at my back. Two pictures of same sample. I took 8 pictures, half were out of focus and the ones with the sun shaded had reflections.

Any ideas for getting decent pictures as well?

Cl 5?
pH 7.5?
 

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kal2002

LifeTime Supporter
Jul 4, 2010
241
Sacramento, CA
This is my problem too. Sometimes I cannot really tell if my pH is 7.5 or not. The color does not match 7.2 and it is a little darker than 7.2 and 7.5 so I would record it as 7.6. The CC test is worse for me. The yellow colors for 2, 3, and 5 sort of blended together. The only time I can kind of tell them apart is when I hold it up agaist the PC monitor when the screen is white.
 

Henry Porter

LifeTime Supporter
Nov 7, 2008
604
Sweden
IMO PH is easier to read than FC with this test. But I have callibrate my eyes with a droptest after each taylor in the beginning, so now I'm pretty sure I can trust my readings a bit better.
I would say that your ph is 7,5, FC is harder to say from the pics but it looks to be up there where you've said.
 

Jersey Devil

Platinum Supporter
Aug 4, 2007
61
Jackson, NJ
Obviously this test is subjective, but it is usually good enough for day to day readings. Get the TF-100 full test kit (there's a link in Pool School and many other places on this site) and use it every week to get accurate FC (and other readings). I have also "calibrated" my eyes against the TF-100 test for FC and agree that your FC is around 5 (as far as I can tell from the pictures). The test is only good up to 5 ppm and you might actually be a tiny bit higher. As far as pH, I guess you might be at 7.6 but that is perfectly fine.

As far as pictures, don't waste your time. It's your pool and you need to control it. Unless you have a super-duper macro-focus camara with lots of pixels your eyes are going to be as good or better than anyone viewing on a computer screen. Get the test kit.

It is much more helpful if you post your full set of readings, including CYA, to get the best advice. That's where the TF-100 comes in if you don't already have one. Very few of us trust pool store analysis.
 

JohnT

Admin
Mod Squad
TFP Expert
Apr 4, 2007
9,614
SW Indiana
The key to the pH isn't dark/light, it's yellow-ness/purple-ness. Yellow is acidic, purple is basic. You can add an extra drop of reagent to make it match more closely without messing things up too badly.
 

tim_pool_newbie

Bronze Supporter
LifeTime Supporter
Oct 6, 2009
168
Nazareth, PA
Do you know what your CYA level is? If you're CYA level is 50 or more, you'll need to be targeting an FC level of greater than 5, therefore this test kit won't accurately tell you your FC level - it will max out at 5. Check out the Pool School on good test kits if you don't already have one. My CYA is at 60 and so I never even do the CL test that you show, and just do the FAS/DPD test included in my TF100 test kit.

As for PH, the test you're running is the only option and I have the same issue as kal2002 where my reading is slightly darker than 7.5 but not quite 7.8 so I usually record that as 7.6. I know the instructions say to do it that way.

Best advice I can give is to just keep testing every day, and after a while you'll find the right place to hold it up to a light source for best viewing and you'll become more comfortable reading your own results.
 

another one

Well-known member
Jul 1, 2010
49
Seattle area, WA
Thanks for all the replies. I have a TF-100 and a speedstir, here's my numbers from a few days ago and 2100 gallons have been drained since then - I'm in the process or lowering my CYA by draining 700 gallons per day - we're on a well that does 3 gallons per minute with a whole house water softner, so I'm trying not to overload it. So far I've drained about 10,000 gallons.

pH - 7.5? - see picture
CL - I get 4.5 with the other test - so I expected to see 4 - 4.5 with the color test.
TA - 85
CH - 220
CYA - 38 (estimate - lower than 40, higher than 30), was 55-60 when I started to drain, want to get it to 20-25 - indoor pool.
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
When I do the pH test, I actually look at the block caddy-corner to compare colors, somehow that removes some of the "it is so close but I can't decide" business. So in your photo I look at the color for 7.5 and compare it to the 2nd down sample (next to 7.8 color block). The shadows behind the vial make it tricky in the photo but even the top block (across from 8.2) looks more like 7.5 than anything else. Maybe higher or lower so I'd say 7.5 on the nose.

As for FC, no way to tell for me. I'd use the drop test.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,849
Sebring, Florida
One caveat about those photos. The color block I see on my screen is significanly off from the colors we see on the OTO test block in real life.....there is no purple at the 8.2 mark.

Subsequently, I suspect the color of the pool sample within the test block is off as well.
 

kal2002

LifeTime Supporter
Jul 4, 2010
241
Sacramento, CA
I am still confused when reading the pH. Seems like my sample always turns out to be much redder in color. When I was trying to get pH to go down to 7.2, my sample did not get that pale orangy color. It was pale but with more red. I just got done shocking at 24 FC. When FC came down to 9.5, I tested for pH and my sample was flaming red. I assumed that it was higher than 8.2 so I added some myriatic acid to bring it down. The question is: are we supposed to try to match the colors on the test block? pH at 8.2 is sort of purplish and I never anything but red red. Thanks.