Trying to lower pH

kaymaza

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Dec 27, 2022
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Jandy Truclear / Ei
Hey everyone so over the last week, I've been trying to get my pH to an ideal level (7.6). For the last 3 days, I've been getting the same pH reading 7.9 despite adding about 4 oz per day for the last 3 days. I checked it today and the pH was 7.9 again with a TA 100. I've been cautious with adding the muriatic acid as I don't want to lower the pH significantly. Pool math says that I should be adding 12 oz based on what my numbers but today I just added 7 oz out of an abundance of caution. Are my concerns warranted? Should I have just went by what pool math is suggesting an added the 12 oz instead? Also, I've been adding the muriatic acid in front of my skimmer basket in the main pool but I've been collecting the water samples from the spa. Is that okay to do? The pool water should be cycling and shared between the pool and spa.

I apologize if this is a dumb question. It's my first pool and my first time managing the chemistry so I just don't want to screw anything up. I've added pictures of pool. It otherwise looks great and clear. Thanks everyone.1000004534.jpg
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mknauss

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pH in the 7's is ideal. Do not try to get to a single number. Test your pH every few days, if 8 or above, test TA and use that information in Poolmath to determine how much acid to add to lower pH to 7.6.
 

bradgray

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Like Marty said, I'd also start with a loose aim at mid 7s. Water is generally pretty happy and forgiving in this range. As you become more accustomed to the personality of your pool, dial it in further.

Being cautious with acid is fine. If you have to lean one way, lean basic (higher pH). But don't stress too hard; it's extended periods outside of the 7s that have consequences.

It's also helpful to note that you have 3 obvious features that will contribute to rising pH. These are partly why your dosages seem to do nothing.

- Saltwater Chlorine Generator
- Spillway on your spa
- Sheer descent feature

 

mgtfp

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Also, I've been adding the muriatic acid in front of my skimmer basket in the main pool but I've been collecting the water samples from the spa. Is that okay to do? The pool water should be cycling and shared between the pool and spa.

Bperry already touched on the acid.

You also shouldn't collect your water samples from the spa. I assume you have direct return lines from the SWG to pool and spa. You keep adding freshly chlorinated water to pool/spa, where it gets diluted into the main body water. The spa has a much lower volume than the pool, so while the SWG is running, FC in the spa will end up being higher than in the pool.

If you want to know the water parameters in the pool, you should take the samples from the pool. Best is as far away from the returns as possible, near the skimmer.

I understand that it's tempting to take samples from the spa because it is raised and you don't have to get down on your knees to take a sample. If that's what you are trying to avoid, then try this:

I made a simple "sample taker" out of a length of PVC and a couple of PVC caps with holes drilled in them. It allows me to grab my sample from well below the surface. It's also great in the winter when the water is cold. And it's much easier on my old bones than lying prone on the deck and sticking my arm down into the water.

I sample at least twice. The first time to rinse out both the sample container and my PVC pipe. The trick is to cover the hole in the end of the pipe before it is plunged into the water, then release the hole once fully lowered. The cap on top remains above the pool's water level. Then cover the hole again while removing from the pool. Release the hole again while holding the other end over the sample container. In this way, the sample is taken from depth, without any of the "higher water" getting into the pipe. I also use a Leslie's sample container. They get just the amount I need for testing, and the squeeze top makes metering out the correct test sample amount very easy and very accurate.

sample pipe 1.jpg
sample pipe 2.jpg


leslie sampler.png
 

Dirk

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You add acid in front of a return, with a slow 1/4" stream, while the pump is running, so that the flow from the return instantly dilutes it and broadcasts it out across the pool, rather than letting it pool in one place or drop to the bottom or get sucked into the skimmer. It's not a huge deal, but it's just good practice, to eliminate the possibility of a chunk of very low pH water doing any harm to your finish or equipment.

If you like my sampler pipe invention, you're gunna LOVE this one:

#85

That whole thread is about my adventures, and mis-adventures, with adding muriatic to my pool. I had a lot to learn back then! (Still do!!), so the whole thread will make you feel a lot better about yourself in terms of being new to pool chemistry. But the "fun" part starts around post #85.
 

mgtfp

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If you like my sampler pipe invention, you're gunna LOVE this one:

#85

That whole thread is about my adventures, and mis-adventures, with adding muriatic to my pool. I had a lot to learn back then! (Still do!!), so the whole thread will make you feel a lot better about yourself in terms of being new to pool chemistry. But the "fun" part starts around post #85.

Just skimmed through a few posts, but this is gold. I'll have to go through the complete thread on a weekend when I'm supposed to do something unpleasant. :ROFLMAO:
 

kaymaza

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Dec 27, 2022
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Henderson, NV
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Jandy Truclear / Ei
Bperry already touched on the acid.

You also shouldn't collect your water samples from the spa. I assume you have direct return lines from the SWG to pool and spa. You keep adding freshly chlorinated water to pool/spa, where it gets diluted into the main body water. The spa has a much lower volume than the pool, so while the SWG is running, FC in the spa will end up being higher than in the pool.

If you want to know the water parameters in the pool, you should take the samples from the pool. Best is as far away from the returns as possible, near the skimmer.

I understand that it's tempting to take samples from the spa because it is raised and you don't have to get down on your knees to take a sample. If that's what you are trying to avoid, then try this:

Okay so should I be testing the pool chemistry for the spa and the pool then? I just thought that they could be treated and treated the same and so I've just been collecting from the spa primarily because I've been using the spa since it's cold out here in Vegas/Henderson. Thank you for the info.
 

Dirk

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Just skimmed through a few posts, but this is gold. I'll have to go through the complete thread on a weekend when I'm supposed to do something unpleasant. :ROFLMAO:
I can't guarantee that slogging through that thread will be any less unpleasant! ;)
 
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mgtfp

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Okay so should I be testing the pool chemistry for the spa and the pool then? I just thought that they could be treated and treated the same and so I've just been collecting from the spa primarily because I've been using the spa since it's cold out here in Vegas/Henderson. Thank you for the info.

I usually don't care about the overflow spa. When there's enough chlorine in the pool, there will be enough in the spa, as long as water is flowing through it. But not necessarily the other way round.
 

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kaymaza

Member
Dec 27, 2022
20
Henderson, NV
Pool Size
15000
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Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Truclear / Ei
Hey everyone just some updates I checked my pH this evening and it was 7.8 with a TA of 100. Because my TA was on the high side and with my pH still on the high side of ideal, I went ahead with the Pool Math app recs and added about 30 oz instead of the suggested 37 oz to lower both the TA along with the pH.

I'm kind of worried that I may have overshot it. My pH meter is getting around 7.1-7.2 and the comparator block looks like the pH is between 6.8-7.2. I've included a pic for reference. What do you guys think? Will I need to raise the pH now? 🤦‍♂️ Disregard the Cl from the comparator block. I didn't add the reagent to check the range of chlorine.

1000004603.jpg
 

Bperry

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Hey everyone just some updates I checked my pH this evening and it was 7.8 with a TA of 100. Because my TA was on the high side and with my pH still on the high side of ideal, I went ahead with the Pool Math app recs and added about 30 oz instead of the suggested 37 oz to lower both the TA along with the pH.

I'm kind of worried that I may have overshot it. My pH meter is getting around 7.1-7.2 and the comparator block looks like the pH is between 6.8-7.2. I've included a pic for reference. What do you guys think? Will I need to raise the pH now? 🤦‍♂️ Disregard the Cl from the comparator block. I didn't add the reagent to check the range of chlorine.

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It’ll be higher tomorrow without doing anything. And the next day it’ll be even higher as well. It’ll be fine. Just keep it in the 7’s. pH is not something you can expect to be stable at a certain number. Best case is you bounce around between 7.2 to 7.8.
 

Dirk

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Not only will it move around a lot, especially now, it takes months of your pH being way out of whack for it to affect your pool finish.* On the low end of the scale for a day is not that, and not something to worry about. As Bperry points out, it'll bounce right back, and is probably OK even today.

* That's not to say you should be lazy about maintaining your pH. I'm somewhat fanatical about it and have taken great lengths to make sure it is always dead on, but that's just me. You don't have to be that compulsive about it, but good water chemistry balance is always the goal.