PH question.

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inkdrip

0
Sep 1, 2018
8
Henderson
After changed the water last fall I’ve always been following the TFP method. It makes a lot of sense and is effective. I have question about how often you guys have to adjust the PH. I couldn’t quite find a direct answer and it has been troubling me because I think my PH goes beyond 8 very quickly. I feel I need to adjust the PH weekly using a whole gallon of 20% muriatic acid. Is this normal for folks living in Vegas area?

So here’s the condition of my pool:

1. Live in Henderson NV. Lots of sun in summer and very hard water.

2. Pool is not new. Definitely more than five years. Maybe more than 10 years. Before it was serviced by some company when previous owner lived here. Water was not changed for years. Everything was way way off the chart. Like diluted by four times and still off the chart. There are cracks here and there but not very noticeable. We fixed one hole when changing the water.

3. Just change the pool water last fall. Used tap water so very hard water. CH is about 400-500. There are still scales but we removed most when changing the water.

4. 40 cya. Not sure if I should use more.

5. Use 10% bleach from Lowe’s.

6. TA is at least 170. Maybe higher.
 
Welcome to the forum!
How are you testing your pool water chemistry? Can you complete your signature so we know pool type, volume, equipment, etc?

With our Colorado River water, your fill water TA is 130 ppm. CH is 250 ppm.
You do need to continually add acid to lower the pH and work down the TA. I push the pH to 7.2 from 7.8 after a new fill or during high evaporation rates as that helps lower the TA.

You should try to get full strength muriatic acid. 31.45%. I get mine at Home Depot.

I suggest you read ABC's of Pool Water Chemistry and consider reviewing the entire Pool School eBook.
You may also want to get the Poolmath app.
 
Thank you mknaus!! Good to know you have to adjust constantly but how often do you do that? Is one gallon per week too frequent? It sounds expensive to me. The 31% acid is almost $10 a gallon.

I used the TFP kit. For CH, I never get that low even with tap water. I always waited until the blue color doesn’t become bluer anymore. Could this cause our reading differences?

Let me figure out the signature. My pool is plaster. I think it’s 16000 gallon? There’s a vacuum running around for eight hours every day. It’s the setting from previous owner. Not sure if it’s too excessive... I do have the pool math. It’s good app.
 
inkdrip said:
but how often do you do that? Is one gallon per week too frequent? It sounds expensive to me. The 31% acid is almost $10 a gallon.
Click to expand...
The amount of Muriatic Acid (MA) use will depend on how quickly your pH bounces back up to 7.8 or so. But as times goes on, with each MA dose, the TA will slowly fall lower & lower. As for the cost, $10 is a bit steep. MA is one of the few things I get at my local pool store only because it's a decent bargain at about $14 for 2 gallons. Shop around and you should find something a bit better. And once you get the TA where you want it, and the pH rise slows down, you'll use less MA.

For the CH test, are you using a speedtir? If not, I would highly recommend it as it really helps (and can impact) the CH, TA, and FC tests. Also, don't forget to update your signature!

I was just in Henderson a couple weeks ago. Wow has that place grown over the years. Yikes! Welcome.
 
Thank you! It makes sense - with ph lowered, co2 comes out and TA is lowered. Then I may not have to use MA as much.

I’m trying to see if other people living in Vegas use a lot of MA or there’s something wrong with my pool or my approach. It may be that with our Colorado water we do need a lot more MA. Based on my measurements the TA from the tap water is as much as 150...this may be an infinite battle. On top of that, we still have residual scales in the pool that would also contribute. But still I think you are right that once I gave it enough acid I will use less.

I’ll shop around to see if I can find cheaper MA. I do shake reaction diligently but I guess stirrer is always better.

Haha, many places in Henderson looks fabulous now. Wouldn’t have moved here if it doesn’t look this nice.
 
Thank you for the article! It seems I should start reducing the run time. It’s not a SWG...sorry if my signature was not clear enough. I now capitalized the NON... I’m just afraid if I don’t do non SWG, people would think I forgot to mention and ask.
 
Ink,

pH rises gradually due to aeration of the pool. We have a similar situation to yours and I think most people with pools have this. Non-TFP methods that use trichlor tablets often require no acid because the tablets are half cyanuric acid. But they require much more CL and frequent water changes... not a good option in my opinion. MA is about half the cost you describe at HD in our area ($11 for a 2-pack). Borates can be added to reduce pH fluctuations. I switched to this a couple of weeks ago and pH is definitely more stable albeit at the high end of the acceptable range. The one-time cost to switch was under $100 for me.

Chris
 

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setsailsoon said:
Ink,

pH rises gradually due to aeration of the pool. We have a similar situation to yours and I think most people with pools have this. Non-TFP methods that use trichlor tablets often require no acid because the tablets are half cyanuric acid. But they require much more CL and frequent water changes... not a good option in my opinion. MA is about half the cost you describe at HD in our area ($11 for a 2-pack). Borates can be added to reduce pH fluctuations. I switched to this a couple of weeks ago and pH is definitely more stable albeit at the high end of the acceptable range. The one-time cost to switch was under $100 for me.

Chris
Click to expand...
Hi Chris,

Thank you for the reply! Now I am certain my pool is not too crazy to ask for that much acid. I agree with you on the tablets. I don't like the accumulation of trichlor -- it makes no sense. There are 2-pack MA at my local HD but they are all 15%....I see there are 30% 2-pack on their website but they are not available in Henderson. how Sad! About borates, I think my TA is already very high so I am thinking I may have to go the other way around, perhaps eventually reach the point you are at:) I cannot be 100% sure.
 
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homegameroom said:
Ditto for me and my pool. Does your spa "waterfall" into the pool? That can cause your pH to rise as well, and it gets worse if the pump is running too much.
Click to expand...
Yes! I think of that too. Water goes about three stairs down from the spa to the pool. That's why I asked about the running time. I am going to just do 4 hour instead of 8 hour per day. I also set it so that it run at night -- I am thinking this way water evaporates slower... and at lower temperature it probably looses CO2 slower as well...
Did you try running it for a short time and does it help with PH?

A bit conflicted/confused about the aeration or letting CO2 out because it helps to reduce TA but also raise PH... I need more time to think it through. It doesn't seem I am the only one confused lol.
 
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Check at Pacific Pool Supply or Fresh Pool Supply - both in Henderson - for acid and chlorine. Hopefully one or the other is a Hasa dealer and has the acid for around $20 for 4 gallons of 31.45% in refillable jugs. If they are a Hasa dealer, they should also have 12.5% chlorine in a similar 4 pack for around $16 or so.

Seriously consider getting the SpeedStir. It makes testing so much quicker and more accurate.

If your spa is overflowing into the pool whenever the pump is running, your pH is constantly going to rise. If you can limit the spillofer to about 30 minutes a day that would help with the rising pH. And maybe work on getting the TA down to 60-70 too..... difficult if tap water is at a TA of 120-150. In any case, get the TA and pH under control prior to considering adding borates.

Aeration doesn't lower the TA. Adding acid lowers pH and TA. Aeration raises the pH while leaving the TA relatively the same.

What type pump do you have? Single speed, 2 speed, VS?

Can you post a full set of test results?
 
proavia said:
Check at Pacific Pool Supply or Fresh Pool Supply - both in Henderson - for acid and chlorine. Hopefully one or the other is a Hasa dealer and has the acid for around $20 for 4 gallons of 31.45% in refillable jugs. If they are a Hasa dealer, they should also have 12.5% chlorine in a similar 4 pack for around $16 or so.

Seriously consider getting the SpeedStir. It makes testing so much quicker and more accurate.

If your spa is overflowing into the pool whenever the pump is running, your pH is constantly going to rise. If you can limit the spillofer to about 30 minutes a day that would help with the rising pH. And maybe work on getting the TA down to 60-70 too..... difficult if tap water is at a TA of 120-150. In any case, get the TA and pH under control prior to considering adding borates.

Aeration doesn't lower the TA. Adding acid lowers pH and TA. Aeration raises the pH while leaving the TA relatively the same.

What type pump do you have? Single speed, 2 speed, VS?

Can you post a full set of test results?
Click to expand...
Thanks so much!! I’ll definitely check out those stores!

My understanding is that the TA comes from the amount of H2CO3, HCO3 and CO3. So if I add HCL /MA, CO2 will come out and that Reduce the amount of H2CO3, HCO3 and CO3.

I have more than 10 years experience doing biochemical experiments so I’d like to think my mixing is rather sufficient without a stirrer...for CH, the solution turns to purple first and I keep adding drops (4-5 drops more) until it completely turns to bright blue. Same goes for TA, the solution will turn kind of dark and then I keep going it eventually turns to bright red.

My tap water:
TA 140-150
PH 7.9-8
CH 325-350

My pool:
TA 160
PH 8.0 and more
CH 425
 
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