Pool not warming up after water change?

[shooter57]

I'm a little stumped that my pool has not returned to previous temperatures after draining and refilling. I had expected to pretty much lose the rest of the summer, but became much more optimistic when my temps were in the mid 70s after the refill was complete. I hoped that I'd be back into the 90s in no time, especially with Indian Summer coming on.

I'm stumped that my temps have gotten stuck at about 85 degrees despite some really scorching days.

Could the higher temps we saw prior to the water change possibly have something to do with the extremely high CYA levels (>200, my motivation to drain the pool) we had before?

My numbers are currently pretty close to where they want to be (though I am fighting to get the TA down).

My current numbers:
FC - 2.5
TC - 2.5
CC - 0
PH - 7.0 (added muriatic acid to reduce the TA, busily trying to aerate the water to bring this number back up)
TA - 140 (still have more acid to add, but don't want to reduce my PH any more than I have)
CH - 300
CYA - 40 (wooHOO!)

With the chemical levels before we drained (CYA thru the roof and NO chlorine) we'd have to leave the solar cover off at times like these because the water got too warm (high 90s).

So... what's going on to keep the pool from reaching water temps we had before?

 

[polyvue]

I'm stumped that my temps have gotten stuck at about 85 degrees despite some really scorching days.

Could the higher temps we saw prior to the water change possibly have something to do with the extremely high CYA levels (>200, my motivation to drain the pool) we had before?

I'd guess that your freezing 85 degree water is a result of cooler make-up water used during the refill, lower overnight temperatures and reduced sunlight (reduced time and less direct) typical for the autumn equinox, which is fast approaching. My Sacramento pool dipped into the mid-70s after only three days without a solar cover. Brrrrr!

Morgan Hill isn't far from San Jose - I'd say you are lucky to have 85 degrees after the cool weather we've had during this past week. Fortunately, the forecast is a warming trend through Monday, so... swim swim swim!

 

[Bama Rambler]

PH - 7.0 (added muriatic acid to reduce the TA, busily trying to aerate the water to bring this number back up)

I think I've found your culprit! Aeration not only raises pH, it also lowers the water temp.

FC - 2.5
CYA - 40

With a CYA of 40 lets bump that FC up to at least 4. After all you've done you don't want to have an outbreak.

 

[anonapersona]

Near San Jose your daytime temps are below 90 and nightime around 60 -65 which give you an average temp around 78. The temperature below ground has something to do with it also and I have no idea about that there but I did once look up the below ground temp in central Mississippi at 3' below ground and was amazed to find it was a balmy 55 degrees in midwinter. I suspect that there is info somewhere out there for subsurface temps in California but the idea is that the ground temp lags the average air temp as the seasons change. But it does cool down.

We are cooling down here in Houston, it actually has felt like Fall for a week or so -- that means that while it still may hit even 100 at some point, it is a pleasant 70-something in the AM. So my pool is struggling to stay at 85, I see it at 82 sometimes.

I had thought that running the waterfall in the heat of the day would keep it warmer, taking heat off the rocks that face the sun. But, I may be wrong, the evaporative cooling may overcome those hot rocks in a short time. I need to check the morning temps when I am running that waterfall, the past few days the air was cooler than the pool so I may have been importing cold instead of heat.

 

[shooter57]

Aeration not only raises pH, it also lowers the water temp.

Wow, that was pretty clueless of me. Thanks Bama.

With a CYA of 40 lets bump that FC up to at least 4. After all you've done you don't want to have an outbreak.

Ya got that right enough. I am following the pool calculator to the letter, but after a day the FC drops from what I'm assuming is 4.0 (based on what the calculator has calculated with the numbers I've entered and 4.0 being the goal) to about 2 to 2.5.

Am I loosing Chlorine quicker than I should be, or should I put more chlorine in than recommended in order to stay at 4.0 over the course of a day? (If that was the case, you might expect the calculator to offset the recommended amount?)

 

[Bama Rambler]

If you look at the Chlorine/CYA chart in Pool School it says that you should target 5ppm so you don't fall below 3ppm. I said 4 just as the middle ground. About 2ppm per day seems to be the normal loss. My CYA is 50 and I loose about 1.5 per day when it doesn't rain a ton (which it has every day for more than a week).

The PC (pool Calc) recommends a range when you set the suggested goal levels at the bottom as "troublefreepool.com". It's up to you to enter "your" target FC in the column.

 

[shooter57]

If you look at the Chlorine/CYA chart in Pool School it says that you should target 5ppm so you don't fall below 3ppm. I said 4 just as the middle ground.

The PC (pool Calc) recommends a range when you set the suggested goal levels at the bottom as "troublefreepool.com". It's up to you to enter "your" target FC in the column.

Ahhh, thanks. I didn't know that the user set the goals, I thought that was done automatically by the program (and yes, I do have troublefreepool.com selected). Sounds like the program provides suggested values but they can be altered.
Thanks once again.

 

[polyvue]

I'd like to revise my previous amazement at your being able to maintain 85 degree water to utter astonishment.

In light of the astute comments made by anonapersona (ground temperature effect) and Bama Rambler (evaporative cooling due to aeration) your 85 degree water is closer to a miracle. My advice stands: swim and enjoy, while it lasts. :-D

 

[shooter57]

I'd like to revise my previous amazement at your being able to maintain 85 degree water to utter astonishment.

In light of the astute comments made by anonapersona (ground temperature effect) and Bama Rambler (evaporative cooling due to aeration) your 85 degree water is closer to a miracle. My advice stands: swim and enjoy, while it lasts. :-D

Boy, pretty sharp contrast to those good folks who are actually trying to be helpful. Didn't your momma ever tell you if you can't say anything nice.....

PV - the real question here is not why is my water is colder or warmer than yours. Maybe if you could get past your envy you'd see that. My question is based on trying to gain an understanding of the factors at play, and are centered solely on my personal experience with my temperatures before and after the water change. Based on previous experience I've had enough warm temps to drive my pool temp above what I'm reading now. The only issues that pertain to this question have to do with what factors may be causing the drop in temperature relative only to my isolated conditions.

Continue to be utterly amazed all you want, maybe my pool' s just better than yours.

 

[polyvue]

Boy, pretty sharp contrast to those good folks who are actually trying to be helpful. Didn't your momma ever tell you if you can't say anything nice.....

She did. I guess I wasn't paying attention.

Continue to be utterly amazed all you want, maybe my pool' s just better than yours.

Surely true. Let me know when your pH is good... I'll send my rambunctious grandchildren (and all of their friends) over to swim in it--they live very close to you--and we'll let them decide.

 

[shooter57]

Let me know when your pH is good... I'll send my rambunctious grandchildren (and all of their friends) over to swim in it.

Maybe them splashing around is just what I need to aerate my pH back to where it should be!

 

[anonapersona]

[quote="shooter57 My question is based on trying to gain an understanding of the factors at play, and are centered solely on my personal experience with my temperatures before and after the water change. Based on previous experience I've had enough warm temps to drive my pool temp above what I'm reading now.

One more idea, does your water come from a reservoir? When water is drawn off a reservior it may come off near the bottom and at the bottom of a reservoir the water temp is very very cold. That cold may persist through some of the water treatment processes I suppose.

But I'd guess that it is more the mean subsurface temperatures as the pipes move water below ground to your home that gave you that cold water.

When cold water comes out of the tap at your house, what is the temperature? The first few gallons might have been warmed by the pipes in the walls but eventually you'd get water that had been mostly underground in at least shallow pipes, the water main is a bit deeper than your home pipes are.

Sorry if you thought I was being unhelpful

 

[shooter57]

Sorry if you thought I was being unhelpful

AP - no, no, no. I never intended that comment for you. Sorry! Your reply was thoughtful and I guessed your intention to be sincere. I thank you for your willingness to try to help.

With respect to the water temp, everything you say is true enough. However, the initial temperature is not what I'm concerned about. It is what it is, and in fact I was pleasantly surprised that the pool temp was as warm as it was once the refill was complete. I expected worse. Sorry if I didn't make that clear in my initial post.

I'm just trying to understand why it doesn't seem to be responding to the elements like it used to before I drained it. I think it's all part of a big chlorine puck conspiracy.

Thanks again for your posts.

 

[fordsbyjay]

I live in south Louisiana and our pool temps have been 80 on cloudy days and 82 on sunny days for several weeks now. Seems to me that 85 sounds about right for this time off the year.

 

[shooter57]

I live in south Louisiana and our pool temps have been 80 on cloudy days and 82 on sunny days for several weeks now. Seems to me that 85 sounds about right for this time off the year.

You know, after we resurfaced the pool with "Tahoe Blue" plaster our typical temps went from the mid 80s to the low 90s. I was always a little surprised about how warm our water was (like I said, there were spells where we'd leave the solar blanket off for a day or two because the temps were in the high 90s.) Now I'm not bragging or intending to make anyone feel bad by stating these facts. Please do not take it that way. My question is strictly academic. The numbers were what they were, after draining the pool and finally getting a reasonable chemical balance in my pool the temps are not normal (based strictly on my own circumstances, mind you.)

It's getting close to the point where I conclude that CYA = degrees :lol:

 

[PaulR]

I think it's not as warm as before because the sun is lower than it was 2-3 months ago.
I think it warmed up as much as it did because the N.Cal. sun is still pretty strong, even though my idiot trees think it's fall and have started turning already.

Air temp would not be much of a factor except as it influenced evaporation; your water won't gain much by conduction from the air, it's essentially all from the sun.
Ground temp also would not be much of a factor, growing up in NE I learned varmints know how deep to dig their burrows so they don't freeze over the winter, and I'd expect the temp that deep (which is only a few feet) to be pretty stable year round.

CYA has nothing to do with it, of course.
--paulr