Chlorine Consumption/high pH in the Desert

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R

rmoors510

0
Nov 8, 2013
25
Las Vegas, NV
Hey all,

Since I've switched to the TFP method to care for my pool, I've learned more about my pool than I would have ever thought. The water looks great, but I have several questions with regards to chlorine consumption and pH. First, the important data:

Test as of 30 minutes ago...
FC - 4
CC - 0
pH - 7.8
TA - 110
CH - Haven't tested recently, but last time was 300
CYA - 50
Borates - N/A

Now the questions:

1 - I'm adding quite a bit of chlorine to my pool every day. Upwards of a gallon a day to keep FC around 6 (per CYA/Chlorine chart in school). The pool HAS passed the OCLT, but after the sun goes down, I'm around 2-3ppm (normally 2). So, my question for you desert dwellers and experts is, does the summer sun really "Chew" off ~4ppm a day? I get 300+ days of sun a year, and during the summer (now) we are around 100-110 degrees F. From about 9am to 4:30pm, my pool is in direct sunlight. My concern is that, at $3 a gallon for 10%, I'm looking at $90 a month! That's not counting the MA, which brings me to my next question...

2 - My pH is constantly on the rise. I drop it down to 7.2 to attempt to lower TA (I've done this at least 5 times... TA was at 120, now at 110), and within a day it's back up at 7.8-8.0. I can continue to try to drop pH to lower TA to hopefully help keep pH in balance, but I'm adding QUITE a bit of MA each time (like 1 to 2 gallons). Again, my cost is now skyrocketing since I'm paying $12 for 2 gallons of MA. I have a spillover spa, so would that amount of aeration cause my pH to rise that quickly?

Bottom-line, I love the TFP practice, but I'm concerned it hasn't been trouble-free to my wallet. If these costs continue, it may be easier to float tabs (blasphemy! I know...) and drain and refill every season. Surprisingly, water costs in a desert are remarkably cheap!

Since I doubt anyone is online this late, I look forward to your responses tomorrow!

Bob
 
My non-expert status says you might want to increase your CYA or perhaps consider a Salt Water Chlorine Generator....might save you some $$

But my pool is half your size, in summer I am in full sun, however I m not in the desert and I lose 2-3 PPM per day....so your numbers don't shock me.

As for the pH - have to resort to the experts...mine is stable...but not spa spillover.
 
Welcome to TFP Bob,

Your use does not seem unreasonable, especially on FC consumption with that kind of desert sun exposure all day. We have people in East Tx with similar loss and Cya levels. Mine is a little less here in West Tx, but I get some shade. I think that 10% you're buying is likely closer to 8%, maybe even less by the time you get it and get it into your pool. I would suggest buying 8.25% somewhere for the same or few cents less per gallon. The 10% you are finding at the Box, Hardware, or even Pool Store sits a while usually, so you likely aren't gaining much by getting it.

Your pH rise seems very normal at that TA and it will slow as that comes down, but yes, your spa is adding to the speed of the rise as well. It's only my opinion, and I am the last person that could be accused of being a tree hugger, but I think you have a responsibility to save as much water as possible in a desert environment. And at some point, it will become more expensive.
 
I am in Florida. My pool gets full sun for most of the day as well. I am adding 80 to 110 oz. a day to keep my FC levels up this summer. For some reason I did not have to add as much last summer. I have passed with flying color the OCLT every time I do it. It is what it is. My pool looks and feels great!

PH-yes your spill over WILL cause it to go up. When I need mine to go up I point my return up and let it make a fountain into the air. It also helps coo the water a little.

Do what works best for you. You have the tools to make an informed decision and you know what will happen if you do X and Z so.............

Kim
 
I don't have the temperatures you do, but pretty much the same sun. Your chlorine consumption sounds a tiny bit high. If they store the pool chlorine outdoors, you're probably not getting a full 10%. Raising CYA up a little bit will also help, and I'd do it via pucks since the slow acid feed pucks provide will also lower TA a bit. I'd start comparison shopping. Watch for the pool guys who come to the neighbors and look in the back of their truck. If you see yellow and orange milk crates, that's chlorine and acid in returnable jugs. Ask where they buy it.

The acid demand sounds familiar. With hard fill water, I've found that every inch I refill is good for two cups of acid. And my pool is a lot smaller than yours. I reduced the flow through the spa to the lowest notch on the multiport valve, and I capped the air intake for the spa jets with an old pan can cap. Less aeration = lower pH rise. Finally, aggressively reducing the TA to around 60 finally got things to settle down.
 
Thanks all. I'm glad to hear it isn't some other issue, but what I suspected... sun. I buy the 10% at Lowes, and it is stored outside (but in a covered area and in a box), so I will look for some stored inside at some other location. I read the articles that discussed raising CYA to limit chlorine consumption, and it sounds like even with a 10ppm bump (to 60), I may not save much as burn-off will be similar, but target FC is higher.

As for pH, I'll continue to drop the TA.

I guess this is just the cost of owning a pool in the summer in Vegas. At least the winter months are easy-going!
 
confirming others comments, I'm in Phoenix, AZ and have full sun on the pool and about 5 degrees warmer than Vegas. I average about 3ppm of chlorine lost per day, which equates to roughly half a gallon for my size of pool. Your pool is a little larger and using a little more daily.
only real difference I see in our numbers is my CYA is around 60.
That might help a little, but like you said, it wont change the equation fundamentally.

The biggest change I have noticed is with a cover. it would appear that a cover drastically reduces the UV elimination of chlorine from the water because my chlorine usage was 75% less when I had a cover on. Now that the water is up to 90 degrees I wont put the cover back on till Sept, but the amount of chlorine protection it gave was a surprise. mostly I just wanted to get in the pool when the kids were in it, and I was hoping it would cut down on evaporation which it also reduced drastically.
 
Just know that the Lowes chlorine could be OLD. At least around here it is. I have seen them take all the jugs off the shelf and rinse them off and clean up the shelf to make them look new!

Is there a date stamp on bleach in stores like Lowes? I am going to look the next time I am there. Hummmmmmmmmmm

Kim
 

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