pH: how much is too much muriatic acid?

Jacquelyn1215 said:

PoolMath has been recommending 2 cups give or take. It's usually 18 oz - that's what I added this a.m.

Click to expand...

Cool - so keep adding it until it is down. I'd go every 15-30 minutes or so with the pool running. That should be well enough mixed. You can walk around brushing the pool to mix it quicker. Wait to swim when adding acid at least 20 minutes.

Jacquelyn1215 said:

Yes, we have a water feature in our sundeck that we haven't been turning on since our pH has been so high. Once we get that down we'll turn it on to work on the TA.

Click to expand...

You'll need to run the water feature 24x7 while adding acid to get your TA down. I went through it it took me a week to drop like 30 points and I added more than 4 gallons of acid.

Do not lower the pH below 7.0-7.2
With each addition of MA to lower the pH, the TA will come down a little.

What is the pH, TA and CH of your fill water?

Are you using PoolMath?
If so, in PoolMath, turn 'Track CSI' on and also share your PoolMath logs so they show in your forum profile. You must use the same username/password in the forums and PoolMath.

Jacquelyn1215 said:

Wow. Okay, so turn on water feature and just keep adding the muriatic in 15-30 min increments til we get it down. Got it. Thanks.

Click to expand...

Just to clarify...

You're adding muriatic acid every half hour with the pump running to bring your pH down. Every time you bring down your pH, your TA will come down some, too. You can actively pursue lowering your TA, which will help with the constantly rising pH, but you might not need to. Your new finish is drinking acid, which needs to be replenished, and this might be all you need to do to stabilize your TA at the same time.

When I first took over my pool, I was obsessed with lowering my TA. I built in-pool sprinklers for that purpose, and ran my pump all the time to aerate the water. And it was working, but it was a lot of hassle. Marty kept telling me "leave it alone, and it'll come down on its own" but I was determined. So I battled TA for a while, and it was coming down, but then it got old, dealing with the sprinklers, so I finally gave up and left it alone, and it ended up coming down and stabilizing all by itself, just as Marty said it would.

So it's up to you, and it wouldn't hurt to post your fill water TA, so we can see what you have. But I have high TA in my fill water, and my regular acid additions control both my pH and TA just fine, no special attention needed for the TA.

Regarding your concern about the constant pH battle... Your pH test is reading 8.0, so you plug that into Pool Math and then add the recommended amount. Only to later see that your pH is still 8.0. Sound familiar? This is probably what's going on: your kit only reads to 8.0, but your pH is likely somewhat higher. Maybe 8.2, or 8.4, who knows. But you plug in 8.0 and you dose accordingly, and your pH does come down when you do. But only from 8.4 to 8.2! Or 8.6 to 8.0. Whatever. You can't tell. But each time you test, you get 8.0, regardless if you actually lowered it some, because you're never getting below 8.0, to a level you can actually read from your test!

So what you need to do is what PoolGate is suggesting. You keep dosing acid until you get into the 7s. Then, and only then, do you actually know what the pH is.

So, you test, you get 8.0 and dose accordingly, say down to 7.6. Then you test again in 30 minutes (pump running) and see what you get. If you get 8.0 again, then you dose again, down to 7.6. You keep repeating that until you actually get 7.6. Then ideally you figure out how many times a week you need to dose with acid to maintain your pH in the 7s. If you test the next day, and it's above 8 again, then even once a day might not be enough. Try to keep your pH in the mid 7s, that's what's good for your new finish.

And because your pool is new, and possibly because you have high TA in your fill water, pH is going to be a constant battle for a while. Maybe a year, maybe indefinitely. That's how my pool is. I'm well past the one-year new-finish break-in period, but I still have to add acid constantly because of the TA in my fill water. Oh well. That's why I automated acid injection, so I don't have to deal with pH every few days. I decided to add the system early on, regardless if I later found out my pH would stabilize once the new plaster was done being new. I figured it'd be nice to have, even if I didn't need it to inject every day, and I might as well get good use out of in in that first year, when for sure it was going to be needed. As it turns out, it's been a good investment, because it's been four years now, and my pool still drinks a lot of acid.

Anywho, just some extra info for you. Hope it helps...

If you're hanging the sock in front of a return, out in the pool, then 24-48hrs after the granules dissolve should be OK, But if you're putting it into the skimmer, you should wait longer. I wait a week, at least, between adding CYA granules (in a sock) in my skimmer and testing for it. There are a lot of variables: the batch of CYA you used, the size of your filter, water temperature, how clean/dirty your filter is, how long you run the pump each day, etc.

Maybe @Leebo should answer: "What's the reason for the "recommended" and "ideal" levels that you see in PoolMath?"

Perfect!

Jacquelyn1215 said:

1. What's the reason for the "recommended" and "ideal" levels that you see in PoolMath? I know they're mostly close but messes with my head every time I see that.

Click to expand...

The reason I couldn't answer this question was because I base my levels on Pool School (here), and what I've learned about my pool, not what the app says. I don't use the apps recommendations, unless they coincide with my own numbers.

For FC I use the TFP-recommended target amount as my minimum, and then I add 1 or 2 for my target. So, for example, this page and my CYA of 70 suggest FC3 as my minimum, and FC5 as my target. But I want to play it safe, so I use FC5 as my minimum, and try to keep my pool from ever getting anywhere near FC3. That minimizes the chance of some odd event trashing my FC to the point where I might get a little green. I target FC6 for my "normal" and sometimes goose to FC7 when guests are expected (extra swimmer load). But if I see FC4 or below, I treat that as an "emergency" and immediately dose back above FC5. It's not unlike setting your clocks fast so you're never late! I know my minimum is 3, but by "pretending" it's 5, I am virtually certain I'll never accidentally get below 3. It's not exactly TFP gospel, but it's what works for me and my pool (and many others here use the same MO). A little extra FC won't harm the pool or the swimmers, and it's cheap insurance. It might burn off a slight bit faster than if I maintained TFP's numbers, but with an SWG a little chlorine loss is no big deal.

For pH, I use the Pool Math calculators. I plug in a full suite of test results, and then fool around with pH values in the CSI calculator until I can get my CSI between -0.3 and 0.0, ideally around -0.15. Whatever pH value gets me in that range, is what I dose for. Right now, with all the other parameters that affect CSI, I'm using pH7.6, which is just about perfect for my eyeballs and skin!

If you don't yet use or understand CSI, that's OK, we'll get you there when you're ready. For now, keep that pH in the mid 7s if you can, and use this chart to determine your FC target.

Jacquelyn1215 said:

1. Our CYA seems to be in a good place now at 60. My limited understanding of CYA is that there's no way to get it out of your pool once it's in, but does it diminish over time or should we anticipate it more or less stabilizing at 60 now?

Click to expand...

It drops over time. Check it once a month (or less if you find it's not dropping enough each month to merit testing each month). And be sure to check it in the Spring before the summer heat starts.

Jacquelyn1215 said:

1. It feels like we are constantly adding muriatic acid to keep our pH in line. I checked and so far for the month of Sept. we've added 2 gallons, 3 quarts. I keep reading that this is relatively normal for summer and for a new pool (ours was just opened in March). Keep in mind we are in Austin and so unlike some lucky northerners, we are nowhere close to "fall" weather. Still very hot. Is this "normal" to add this much this often? I'd say we add acid every other day or so based on what Pool Math recommends.

Click to expand...

Normal is what's normal for your pool! Trust the testing. Dose as needed. My "new" finish, after five years, still drinks acid as much as ever. It has to do with the high TA of my fill water. It's why I automated acid dispensing. Your pool is going to need what it needs. Your TA looks OK, so your acid consumption is going to be what it's going to be. You can wait until next year to see if it's going to come down any. Or at any point we can talk about automating acid dispensing if you tire of doing it manually.

Jacquelyn1215 said:

1. Our FC has been increasing this week. I don't even know the last time we added chlorine- months ago for sure. We have a SWG and to be completely honest I don't know much about it though under the Chemistry tab on the IntelliCenter2 app that we use, there is an area for IntelliChlor where we can change output. For a long time we had it at 100% and then when our chlorine got where it needed to be we dropped it to 50%. We've had it at 25% for about a week now and I'm wondering if that needs to be further lowered? Pool Math indicates our FC is outside of the recommended range and it recommends SLAM (which I've never done so maybe more questions on that!), BUT it also says: "There is no recommended chemical to lower FC levels. Exposure to sun can help to speed up the process." That last part confuses me because we've had nothing but exposure to sun every day. So I'm confused about what to do here re: FC.

Click to expand...

Your pool's FC consumption will vary by season (amount of sunlight and air temp). And also by pool use (the more swimmers, the more you'll lose FC). Expect to adjust your SWG output regularly, all year round. That might be three or four times a year, or every month, if your pool's conditions change that often.

You don't try to remove FC. If it gets too high, you just turn off the SWG for a while and the sun and the other conditions will just use it up. Then you turn the SWG back on when the FC has dropped to your target level. Simple.

You just have to keep playing with the SWG runtime and/or output settings until you find the combo that works for your pool. But here's a tip that will help. Don't try to raise and lower your FC by adjusting your SWG. You'll get into a never ending yo-yo cycle, because the SWG can't add a bunch of FC quickly, nor can it remove any (of course). The SWG is only intended to maintain the correct level. So:

If your FC is low, dose it back up to the correct level using liquid chlorine, then turn up your SWG by 5%. Test the next day, at the same time each day, and repeat the process until FC holds. Always dose back to the correct FC level using liquid chlorine, then adjust the SWG. Don't try to raise the FC using the SWG.

If your FC is high, turn off the SWG for a while until the FC drops to the correct level, then turn the SWG back on and adjust it down by 5%. If it's high the next day, repeat that process.

If you try to lower FC just by turning down the SWG, without first letting it drop down naturally, you'll overshoot the proper setting. Same for if you try to raise FC using just the SWG. That's the yo-yo affect.

Hope that makes sense.

Dirk said:

Your pool's FC consumption will vary by season (amount of sunlight and air temp). And also by pool use (the more swimmers, the more you'll lose FC). Expect to adjust your SWG output regularly, all year round. That might be three or four times a year, or every month, if your pool's conditions change that often.

You don't try to remove FC. If it gets too high, you just turn off the SWG for a while and the sun and the other conditions will just use it up. Then you turn the SWG back on when the FC has dropped to your target level. Simple.

You just have to keep playing with the SWG runtime and/or output settings until you find the combo that works for your pool. But here's a tip that will help. Don't try to raise and lower your FC by adjusting your SWG. You'll get into a never ending yo-yo cycle, because the SWG can't add a bunch of FC quickly, nor can it remove any (of course). The SWG is only intended to maintain the correct level. So:

If your FC is low, dose it back up to the correct level using liquid chlorine, then turn up your SWG by 5%. Test the next day, at the same time each day, and repeat the process until FC holds. Always dose back to the correct FC level using liquid chlorine, then adjust the SWG. Don't try to raise the FC using the SWG.

If your FC is high, turn off the SWG for a while until the FC drops to the correct level, then turn the SWG back on and adjust it down by 5%. If it's high the next day, repeat that process.

If you try to lower FC just by turning down the SWG, without first letting it drop down naturally, you'll overshoot the proper setting. Same for if you try to raise FC using just the SWG. That's the yo-yo affect.

Hope that makes sense.

Click to expand...

In addition to the above advice, if you test every day and can see the FC rising, just directly lower the SWG % a notch and check again the next day. No need to shut it off unless it’s been a while since you tested and it’s WAY over what it should be.

Bperry said:

In addition to the above advice, if you test every day and can see the FC rising, just directly lower the SWG % a notch and check again the next day. No need to shut it off unless it’s been a while since you tested and it’s WAY over what it should be.

Click to expand...

While B's advice will work, it will take longer to dial in your SWG setting that way (and that's fine). My MO will get you to the proper SWG setting faster. Neither method is wrong. The MO I suggested is, in essence, performing mini-chlorine loss tests each day. If you test each day, at the same time, and notice your FC higher or lower, you can adjust the SWG output accordingly. But if you don't restore the FC to the proper level each time, you don't really know exactly how the SWG is contributing to FC rise/fall. This is a confusing concept, I admit. And if you don't want to use it, then that's fine, it'll just take you a bit longer to find the right setting. Your FC can ride up without issue to your swimmers or your pool. Just be sure it doesn't drop too low.

Jacquelyn1215 said:

Pool Math indicates our FC is outside of the recommended range and it recommends SLAM

Click to expand...

This is odd. I don't know why it would do that if your FC is high. Are you testing CC? You can read the SLAM page, specifically the part about what requires a SLAM. If your water is clear, and you see no algae, you're probably OK. But that raises another matter. In your test results chart, I don't see a column for CC. The CC test is a companion to the FC test, and it's very easy to perform each time you test FC. You should do so each time. CC can be used as an indicator that you might have an algae issue.

It's OK to see some CC, like around 0.5 or less. That's normal and expected. It just means your chlorine is "chewing" on something and ridding it from your pool. But if you see CC levels above 0.5, then that's a yellow flag that something might be amiss. So test it each time you test FC.

Dirk said:

While B's advice will work, it will take longer to dial in your SWG setting that way (and that's fine). My MO will get you to the proper SWG setting faster. Neither method is wrong. The MO I suggested is, in essence, performing mini-chlorine loss tests each day. If you test each day, at the same time, and notice your FC higher or lower, you can adjust the SWG output accordingly. But if you don't restore the FC to the proper level each time, you don't really know exactly how the SWG is contributing to FC rise/fall. This is a confusing concept, I admit. And if you don't want to use it, then that's fine, it'll just take you a bit longer to find the right setting. Your FC can ride up without issue to your swimmers or your pool. Just be sure it doesn't drop too low.

Click to expand...

That’s a good point about topping up the chlorine each day. I run mine a bit hot so I can go a couple days of low production without much issue. If I get a few days in a row where it’s low, I’ll crank it up a bit more based on gut feeling. Usually find the right setting within a few days.