Does pH change when covered/with lack of sunlight?

[elsie]

Hi Janet, thanks! I have 8-ft-long double-tube end-to-end water bags around the pool so not even a piece of pine straw or snail will make its way into the pool until I uncover next June (curiously, snails come from the ground here in central AL, far from the coast--can you tell I'm not a native?)! Virtually nothing has changed since I covered it except lack of sunlight. I sure wish I could keep it open year-round like you do (but then there would also be the expense of running the pump). The trees really preclude that. In my naïveté 8 years ago when I moved from the north and landed here and bought the property I uncovered it Jan. 1st after all the trees were bare, only to experience week after week of trees dropping various things in the spring - I mean, the stuff gets so deep you can almost shovel it. You can imagine what it has the capacity to do to a pool/pump, esp. the impeller.

Chem geek, when I took a test sample last night, the water was still fairly warm - I'd guess 81-82 (although this will change fast now that the nights are cooling off). By "anemic" I mean that there was no intensity of hue - it was weak, or, anemic. If I had to extrapolate at all, I'd say it was low vs. high. There was no pink to it at all. I'll retest tonight and look at it more critically. Still, I don't understand why it would abruptly change since the time it was covered when the pH was stable all season long except for having to add two cups of acid every few weeks. That's why I wondered if sunlight is the change component. Nothing else seems to make any sense. Alas, it was easier these past two seasons just not testing pH as I never worried about it. That said, with pools, ignorance is not bliss.

[chem geek]

It sounds like maybe the pH drops you are using are the wrong one for your test kit. The R-0014 drops are for the K-1000 type test kits with the smaller (20 ml ?) viewing tube while the R-0004 drops are for the K-2000 type kits with the larger (44 ml) viewing tube. Either that or the pH indicator dye might be too old.

[elsie]

No, it's the right phenol red - I use the AquaChem OTO kit, buying the Aquachem replacement phenol reds as the tube never needs replacing. It's the same kit I used all summer and when I covered the pool. In fact, for this most recent test I used both an almost-empty phenol red and a new replacement phenol red I had not yet opened, and both times the colors were the same, which is an ever-so-pale orange. Clearly, my pH is not high, it must be low. It's just so pale it doesn't begin to match any of the colors on the tube and frankly I don't know how to extrapolate that reading.

The other night I took a water sample and left it outside in the light and retested at night, and got the same result.

The only variables which changed when I covered the pool 2-1/2 weeks ago and now are:

1. Pump is run only an hour a day vs. 24-7 when pool uncovered;
2. Water is devoid of natural light;
3. New cover; and
4. Water sample taken at pump basket instead of directly from pool.

So, the conundrum continues. I guess I should add some Borax?

By the way, early on in the season I happened to be at an Ace Hardware store and bought their brand OTO kit. When I tested the water after uncovering the pool it was a similar weird color. I remembered this happened once before when I bought another brand OTO from Home Depot. So I went back to the AquaChem sold by Walmart (in both cases), and got the correct pink color. I should've brought Ace's back and told them that their OTO test kit could be ruining a lot of liners because it was so inaccurate. At least that was my conclusion - and a very scarey one at that.

[chem geek]

So, the conundrum continues. I guess I should add some Borax?

Yes, you can use 20 Mule Team Borax to raise the pH. If the TA were very low as well, then you could use Arm & Hammer Super Washing Soda (careful: NOT the laundry detergent) instead or some of each depending on how much the TA needs to be raised.