What to aerate with?

Problems relating to pH and total alkalinity.
Increase ph, increase TA. Reduce pH, reduce TA.
pH chemistry advice and techniques for the pool.
Henry_R
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Location: Houston, Texas USA

What to aerate with?

Postby Henry_R » Mon 15 Aug, 2011 01:10

Ok, I've tried to use the search function for this but it's not helping or I'm not asking the right question, GIGO I guess.

What do you use to aerate a pool? I saw mention about using an air compressor.
I have a 110psi compressor, but it's only a 1 gallon unit and so likely not usable here.

What do people with limited resources use?


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chem geek
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What to aerate with?

Postby chem geek » Mon 15 Aug, 2011 02:04

You can point your returns upwards and run your pump on high (if it is 2-speed or variable speed) so that the water breaks the surface creating waves. If you have fountains, spillovers, waterfalls or other aerating water features, you can run them. A picture of using a compressor with a hose with tiny holes is shown here or you can create your own aerator attached to a return as shown here and here .
Henry_R
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Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

What to aerate with?

Postby Henry_R » Mon 15 Aug, 2011 08:47

chem geek wrote:You can point your returns upwards and run your pump on high (if it is 2-speed or variable speed) so that the water breaks the surface creating waves. If you have fountains, spillovers, waterfalls or other aerating water features, you can run them. A picture of using a compressor with a hose with tiny holes is shown here or you can create your own aerator attached to a return as shown here and here .

That's an interesting device. I wonder what I'd use for a weight? I'd have to think of something. I don't have anything like the black weights shown in the photo.

That compressor in the photo is lot more robust than mine. My compressor has a 1 gallon tank and that one looks like a 3 at least maybe 5. He didn't mention what pressure output he set his compressor to either.
My one gallon tank empties fast at full output and take 10 minutes to refill. For $50 I can't complain since all I use it for is cleaning my computer and it's long paid for itself (cheaper than $5 for compressed air cans).

But my neighbors would complain about the noise it would make refill constantly if I had to use it for this purpose. I have to put it in another room to fill whenever I use it to clean my computer. It's like having a jet engine in my room. :shh:

We don't have any adjustable jets on our return ports. They're just straight. They're what was here before the replaster last year so they didn't bid to put anything new in there. Neither do we have anything like a fountain, spillover or waterfall. Those are on our HOA wishlist though. :)

How long do people usually aerate? The only reason we would need to is if I convince the powers that be here to add some borates to the pool. I was talking yesterday about it, but since the first step is lowering TA
I need to know about aerating beforehand so I can get it back up once it's down. The borax is cheap and likewise the muriatic acid. I just want to know how to do this so I can present it to laypersons I have to deal with here.

We just drained down to 1' in the shallow end yesterday, and refilled last night. We probably cannot do this anymore since we are in a drought but voluntary water restrictions.

We had a bunch of alum in there to pick up debris(yes I know there are better flocs, but this is what my HOA was sold. The last time they were given a freebie and it worked so they got a sale this time). Anyway I vac'd the remaining stuff from the bottom to waste after we let the pool settle overnight without the pump running and no addition of chlorine...yet until we get the water tested. With a 50% drain it should have drop half the CYA... I hope. :shifty:

Last time it only seemed to go down 20 points or the test was off. (pool store people again!) Finally going to different pool store vs only one though.

There's still some particles in the water even after vac'ing and with it having settled.
Perhaps that will be ok once I get the filter going normally. I have to wait for the water level to get higher since I vac'd to waste and there's not enough water to keep the pump happy yet.
Money talks!? All it ever says to me is "goodbye!".
chem geek
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What to aerate with?

Postby chem geek » Wed 17 Aug, 2011 23:45

As the lowering TA procedure describes in this post you aerate with the pool at low pH. The lower pH plus aeration has the carbon dioxide outgas faster. As for how long, it's a fast process when the TA is high (noticeable pH rise in an hour or so), but a slow one as the TA gets lower. Think days, not hours. Keeping the pH low by adding acid whenever you see the pH rise makes the process go faster (as does more aeration). On the other hand, if you have that hard of a time getting the pH to rise when the pH is low and you are aerating, then your pH is apparently already reasonably stable so you may not need to lower the TA any more at that point.
Henry_R
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Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

What to aerate with?

Postby Henry_R » Thu 18 Aug, 2011 02:13

chem geek wrote:As the lowering TA procedure describes in this post you aerate with the pool at low pH. The lower pH plus aeration has the carbon dioxide outgas faster. As for how long, it's a fast process when the TA is high (noticeable pH rise in an hour or so), but a slow one as the TA gets lower. Think days, not hours. Keeping the pH low by adding acid whenever you see the pH rise makes the process go faster (as does more aeration). On the other hand, if you have that hard of a time getting the pH to rise when the pH is low and you are aerating, then your pH is apparently already reasonably stable so you may not need to lower the TA any more at that point.
Hmm... I was finally able to convince my HOA to listen to reason. :clap:

I've been talking of the benefits of adding borates at your suggestion in the previous thread.
(I'm finally getting through to the powers that be here after almost four weeks. They've even just bought a TFT100 kit too! It should be here mid next week.)

However the addition of borates requires lowering pH w/ muriatic acid to lower TA and then balancing pH back up to 7.2-7.4 (If I've understood the method right) so I would need to find an effective way to aerate.
I think? I'm not sure I'm going to be able to find a suitable method though for my situation.
I guess we'll have to live without additional borates for now. We still might need to lower TA a little though at some point. It's latest test put it at 120 which is high side of normal IIRC.
Money talks!? All it ever says to me is "goodbye!".
Henry_R
Swimming Pool Pro
Swimming Pool Pro
Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

pH and TA changes

Postby Henry_R » Sun 28 Aug, 2011 11:22

chem geek wrote:As the lowering TA procedure describes in this post you aerate with the pool at low pH. The lower pH plus aeration has the carbon dioxide outgas faster. As for how long, it's a fast process when the TA is high (noticeable pH rise in an hour or so), but a slow one as the TA gets lower. Think days, not hours. Keeping the pH low by adding acid whenever you see the pH rise makes the process go faster (as does more aeration). On the other hand, if you have that hard of a time getting the pH to rise when the pH is low and you are aerating, then your pH is apparently already reasonably stable so you may not need to lower the TA any more at that point.
I'm getting to the point where we might need to aerate, but I'm still not able to find an effective aerator.

On Tuesday we got the TF100 kit, btw. After a long time of lobbying. :clap:

Over the last 5 days TA has risen from 150 to 170 then back to 150, and pH has been bouncing a little up to 8.2 twice then to 7.8. On Tuesday we got the new TF100 test kit. I'm partially familar with how to do the tests, but it's been almost a year so I'm having to re-learn. The FAS-DPD chlorine test is brand new though so I hope I've been doing it correctly.

Anyway, on Wednesday morning I tested the chlorine using the FAS-DPD for the first time TC/FC/CC were all zero. FAS didn't even change color at all. I did a pH test and it was higher than 7.8, but not quite as dark as 8 or so it seemed to my eyes. TA=150 CYA=50 CH=300
My neighbor had the water tested at the pool store where she got more 10% chlorinating liquid.

Their test showed showed pH as 8.2, TA=120. It said to add 2 pts+3oz of muriatic acid on their printout.
We had some 31.45% muriatic from some cleaning last summer so I put in about 1/2 the dosage recommended since I also needed to add chlorine and I wasn't sure how to compensate for it's acidity when adding MA. I used my own pH test that night again after my neighbor added 1 gallon and 8-10oz cups of chlorine to the pool and the FC was around 11 and CC=1. She must have not added the stuff very accurately or being new I did the FAS-DPD chlorine test wrong (possible) The pH was still 8.2 and TA=160 by my test so I added the MA late.
It rained very hard for 30 min-1 hour, not long after I added the MA.

On Thursday morning pH=7.5, TA=150 FC=3. The rain dumped dirt and leave in the pool so it burned off most of the chlorine overnight. Added more chlorine to bring FC to 8 which is high end of normal for CYA=50.
No CC showing up on FAS-DPD chlorine test at all, btw.

Friday, TA went up to 160 but pH remained normal 7.8. FC=5.5 more chlorine added.

Yesterday, pH spiked to 8.2 again, TA=170 FC=1.5 The pool was clear and I didn't have time add MA or chlorine in the morning. I added chlorine late last night. I don't remember if I added MA and I didn't write it down. I was tired and I forgot. pH this morning is down to 7.8, TA=150 again so perhaps I did add some MA.

I added 2-8oz cups to reduce the pH a little more and maybe the TA too this morning. I wish I could get the TA to 120 and keep it there. BTW, how long after adding MA should the water show a pH change? Turn over rate of the pump/filter maybe 6 hours?

TA and pH are rollercoastering and TA bounce seems to be the source. Does this sound right?

Is there such a thing as connecting a hose to a return port of a pool? If I could do that I could use the pool returns as aerators. As I've said before we don't have jets on the returns so aeration is really a challenge.
I do have a neighbor with a compressor, but if we need to aerate for a long time we're not going to be able
to do it for lack of AC outlet power near enough to the pool. One tank fill at a time is going to be hard to do.
Money talks!? All it ever says to me is "goodbye!".
chem geek
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What to aerate with?

Postby chem geek » Wed 31 Aug, 2011 20:47

Your pH is rising because your TA is too high. 120 ppm is NOT the target you should be shooting for. When using hypochlorite sources of chlorine, it should be far lower, usually no higher than 80 ppm and if your pH is still rising too quickly at that TA you could go even lower, but for now get it down to 80 ppm using the procedure I gave to you. If you lower the pH to 7.0, then it should rise reasonably quickly so that you can add more acid to keep it down -- the early phase of lowering the TA will be faster and easier. Right now with the pH rising so quickly, you don't really need to worry about aerating -- you should instead be adding acid more frequently to keep the pH down at 7.0 during this process. As the TA gets lower, the rate of pH rise will slow down so the process takes longer, but then again that's near the end of where you need to be since the goal is to slow down the rate of pH rise.

The TA moves a little with the pH so don't worry about the "bounce" of it. It's just way too high and is causing your pH to rise, period. Remember that it takes 25-1/2 fluid ounces of full-strength Muriatic Acid (31.45% Hydrochloric Acid) to lower the TA by 10 ppm in 10,000 gallons. Use The Pool Calculator to calculate dosages but you won't be adding the total amount of acid to lower the TA at once, but instead add enough to get to 7.0 pH during this TA lowering process (again, read the procedure I linked to).
Henry_R
Swimming Pool Pro
Swimming Pool Pro
Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

What to aerate with?

Postby Henry_R » Thu 01 Sep, 2011 02:23

chem geek wrote:Your pH is rising because your TA is too high. 120 ppm is NOT the target you should be shooting for. When using hypochlorite sources of chlorine, it should be far lower, usually no higher than 80 ppm and if your pH is still rising too quickly at that TA you could go even lower, but for now get it down to 80 ppm using the procedure I gave to you. If you lower the pH to 7.0, then it should rise reasonably quickly so that you can add more acid to keep it down -- the early phase of lowering the TA will be faster and easier. Right now with the pH rising so quickly, you don't really need to worry about aerating -- you should instead be adding acid more frequently to keep the pH down at 7.0 during this process. As the TA gets lower, the rate of pH rise will slow down so the process takes longer, but then again that's near the end of where you need to be since the goal is to slow down the rate of pH rise.

The TA moves a little with the pH so don't worry about the "bounce" of it. It's just way too high and is causing your pH to rise, period. Remember that it takes 25-1/2 fluid ounces of full-strength Muriatic Acid (31.45% Hydrochloric Acid) to lower the TA by 10 ppm in 10,000 gallons. Use The Pool Calculator to calculate dosages but you won't be adding the total amount of acid to lower the TA at once, but instead add enough to get to 7.0 pH during this TA lowering process (again, read the procedure I linked to).
Do I need to correct for CYA when reading TA? My neighbor had the water tested for phosphates to see if we needed some phosfree (I know we shouldn't need that if the chlorine is right, but I cannot talk her out of using it). Anyway, inspite of my reading 170-160-150-130, etc over the last week the pool store reading is 110 now. I'll test this for myself in the morning.

I know they shouldn't be relied on, but my question is, is it possible their computer system is correcting for CYA and so a lower reading results? I saw a chart that was supposed to be the TA correction factors for a given pH.

pH has been stable for the last few days I really don't want to mess with it. Not to mention I don't control the money and I'm uncertain if I can convice those to who to buy more muriatic acid or even dry acid.
The MA we have been using is from last year when we had the pool light conduit replaced, the man who did the work left the MA for getting rid of some cement stains on the deck. We had almost a full gallon when I first added 4 cup fulls almost two weeks ago now. Before then I've never added acid to this pool.
Whether the pool man did routinely I don't know. I know I don't remember his carrying any around with him.

I have less than 2 qts left. One more reason I was conservative with the MA usage.

I will have to work on this. We should have less bathers over the next few weeks too so that will make lowering the pH and TA less of an issue to the pool being used.
Money talks!? All it ever says to me is "goodbye!".
chem geek
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What to aerate with?

Postby chem geek » Sun 04 Sep, 2011 00:54

You do not adjust TA by the CYA. The only time that adjustment is needed is for calculating the saturation index, but tools such as The Pool Calculator will make that adjustment for you automatically. You just enter in your actual TA reading. I have no idea if the pool store is adjusting their TA reading, but I wouldn't worry about that and would trust your own results from your own test kit.

Your pH may be becoming more stable due to the TA getting lowered. As I posted in another thread you started on another forum, it's a pay-me-now vs. pay-me-later situation with lowering TA. The procedure simply accelerates a process that occurs anyway over time. There is no escaping having to add the acid -- it's just whether you lower the pH and aerate (if possible -- just lowering the pH helps by itself) to accelerate the process and add the acid over a shorter period of time vs. adding less of it (per unit time) over a much longer period of time.
Henry_R
Swimming Pool Pro
Swimming Pool Pro
Posts: 126
Joined: Fri 20 Mar, 2009 21:41
My Pool: HOA Community Swimming pool built approx. 1971.
In-Ground, Plaster 34x18 3.5-6' deep, Sta-rite P2R A5D-120L pump, A.O. Smith centurion 1HP (uprated 1.25HP) motor,Hayward S244S filter(new 2011), Rainbow Lifegard Chlorine/Bomine feeder; new replastered June 2010
Location: Houston, Texas USA

What to aerate with?

Postby Henry_R » Sun 04 Sep, 2011 22:02

chem geek wrote:You do not adjust TA by the CYA. The only time that adjustment is needed is for calculating the saturation index, but tools such as The Pool Calculator will make that adjustment for you automatically. You just enter in your actual TA reading. I have no idea if the pool store is adjusting their TA reading, but I wouldn't worry about that and would trust your own results from your own test kit.

Your pH may be becoming more stable due to the TA getting lowered. As I posted in another thread you started on another forum, it's a pay-me-now vs. pay-me-later situation with lowering TA. The procedure simply accelerates a process that occurs anyway over time. There is no escaping having to add the acid -- it's just whether you lower the pH and aerate (if possible -- just lowering the pH helps by itself) to accelerate the process and add the acid over a shorter period of time vs. adding less of it (per unit time) over a much longer period of time.
I've not tried to use any correction for CYA. I just wonder if the pool stores do since it would clear up some reasons their tests show way lower. It's going to have to be pay-me-later, I guess. Since even if pH goes up now I don't have an MA nor other acid to lower it anyway. So far so good though.

pH is staying steady for today at least. I just measured pH to be between 7.5 and 7.8. The color is too light for 7.8 and too dark for 7.5 so it's between them, 7.6-7.7? I put the sample up to a light with CFL bulbs and it shows up better.

TC=5.5, FC=4.5, CC=1 I added chlorine to bring FC to 8 this morning so I lost 3.5ppm FC during the day and CC went up by 0.5 ppm. This is with windblown debris primarily leaves and some dirt in the pool and about three bathers this afternoon. I vac'd, but the wind makes it hard to keep up with. I'm going to vac again tomorrow.
It's going to be hard to keep up with this as autumn sets in. It's usually late coming in Houston, but leaves begin blowing off trees right about now.
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