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Changing water how long to aerate?


jrspa

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First time changing the water this weekend.  PH of our water is high, will drop it and aerate it.  From what I read, this will raise the PH back up.  

How long do you aerate it to gas out the acid and how frequent can I keep adding PH down to get it where it needs to be?  (Every hour, every 6 hours?)

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Please correct me if Im wrong about the question your asking.    I'm not here to start anything, just to help those who need it.  Do you have the understanding that Aerating your water, it will somehow change water chemistry?

Aerating your water will not Change your water chemistry in any way.  Do you have test results of the Alkalinity and also the PH?  If your not familiar with Alkalinity, its is a buffer for the PH.  Generally speaking PH will follow ALK.  If your Alk is high, PH will follow it high, and if the ALK is low the PH will follow it low.  Properly balanced ALK will hold the PH balance.  Proper levels for ALK is 80-120.

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Thanks for replying. 

I remember reading, if ph is high, lower it with dry acid to where you want it, run the jets,  this will gas out the acid and raise the PH.  Continue to do that till the PH doesn't rise.   

My personal experience and I am a complete novice, I had issues with the ph.   I would get it down to the 7.5 area.  If I didn't use it, it would stay, but once I used it, the next day, the PH would be high 8s.  

My water ph didn't stabilize till the TA was around 30.

Any suggestions?  

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 Because I don have a water sample for a full analysis, I would suggest taking your water to a pool professional.  If they use a computerized water lab, it will use the Langlier Index to get it balanced.  Your statement about the ALK being at 30 before the Ph would stabilize, tells me that the water is way out of balance.  Without a full analysis, its just shooting into the dark.

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On ‎3‎/‎20‎/‎2017 at 2:27 PM, Patrick Doyle said:

Please correct me if I'm wrong ...

Do you have the understanding that Aerating your water, it will somehow change water chemistry?

Aerating your water will not Change your water chemistry in any way...

In actual fact, you are wrong. Aerating the water in a pool or a hot tub will increase the pH. Aeration drives carbon dioxide out of the water by increasing the surface area of contact with air. When carbon dioxide is dissolved in water, it forms carbonic acid. Reducing the amount of carbon dioxide in the water reduces the concentration of carbonic acid, thus raising the pH.

 

@jrspa: As to how long it takes to raise the pH by 0.1 depends on how much aeration you have going. The best way to find out is by doing it. In a hot tub, the increase is not very fast. You might try running everything you can for a few hours and retesting to get an idea of how fast. If your hot tub has a feature that actually blows air into the water, then it might be faster.

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@MPurcell  

Thanks for posting, just drained and filled my spa.  Added some bromine reserve, 1 TSPL dry acid, 1.5 chlorine free shock, some scale, and let it run for a hour and added 2 bromine tabs.  Currently water is at 65 degrees... 

I'll post my water analysis once it's at temperature.  

I notice a difference in the water appearance already.  After chasing PH and TA numbers after initial fill, maybe a month later, I noticed when the jets were on high, almost a seltzer effect of the water.  Almost like when you pour a glass of soda into a glass, you get a lot of fizz.  I guess it happened slow enough over a month that it wasn't noticeable but I just ran the pumps on high and that effect is now gone.  I do know I was adding dry acid, then baking soda, that acid, then soda etc... 

Would love some advice after I post my numbers...  Seems this site is getting less traffic but if anyone can help I would so much appreciate it

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TA is around 110 PH is at 8.2 temperature is 74, bromine is just showing some color on the Taylor drop kit.  Long way to go to get the temp up but wanted a reading before bed.  I put 2 bromine Tabs into a float when the water was filled.   Will let it run overnight.  

My meter is spinning out of control LOL....  Gofundme for my next electric bill???  LOL 

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I'm not very experienced, as I have had my hot tub for only about a month and a half. But, I have been doing a lot of reading and may be able to help out a little. I am managing a bromine spa using 1" BCDMH bromine tabs in a floater and potasium monopersulfate (MPS) as an oxidizer. I also use standard 8.25% bleach as an oxidizer sometimes. I used 100% sodium bromide to create a bromide bank of approximately 30 ppm by calculation. I will be happy to help out with what I have learned so far.

I have a few questions. What did you use to create the "bromine reserve" and how much? You say you added some "scale" so what product is that exactly? I would assume your bromine tabs are BCDMH (BromoChloro-5, 5-dimethylhydantoin). What is the chlorine free shock, is that MPS? I also need to know what test kit you are using and in particular which bromine test. Is it the OT shades of yellow or the DPD color comparator shades of pink? Or do you have the FAS-DPD titration bromine test?

With pools and maybe also chlorine spas, the normal problem with pH is rising numbers, but I have had the opposite problem and have had to push up my total alkalinity to keep the pH from falling. The BCDMH tabs are acidic and the MPS is also slightly acidic, if your total alkalinity is low, around 40 to 60 ppm as is often recommended for a hot tub, then the pH will push down pretty quick. Your TA of 110 ppm is probably about right. Your pH is a little too high at 8.2. You should probably be down to at least 7.8 before using the tub. I try to keep mine around 7.5.

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On 3/20/2017 at 11:18 AM, jrspa said:

First time changing the water this weekend.  PH of our water is high, will drop it and aerate it.  From what I read, this will raise the PH back up.  

How long do you aerate it to gas out the acid and how frequent can I keep adding PH down to get it where it needs to be?  (Every hour, every 6 hours?)

You should read this thread.

 

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On 3/22/2017 at 0:21 PM, MPurcell said:

I'm not very experienced, as I have had my hot tub for only about a month and a half. But, I have been doing a lot of reading and may be able to help out a little. I am managing a bromine spa using 1" BCDMH bromine tabs in a floater and potasium monopersulfate (MPS) as an oxidizer. I also use standard 8.25% bleach as an oxidizer sometimes. I used 100% sodium bromide to create a bromide bank of approximately 30 ppm by calculation. I will be happy to help out with what I have learned so far.

I have a few questions. What did you use to create the "bromine reserve" and how much? You say you added some "scale" so what product is that exactly? I would assume your bromine tabs are BCDMH (BromoChloro-5, 5-dimethylhydantoin). What is the chlorine free shock, is that MPS? I also need to know what test kit you are using and in particular which bromine test. Is it the OT shades of yellow or the DPD color comparator shades of pink? Or do you have the FAS-DPD titration bromine test?

With pools and maybe also chlorine spas, the normal problem with pH is rising numbers, but I have had the opposite problem and have had to push up my total alkalinity to keep the pH from falling. The BCDMH tabs are acidic and the MPS is also slightly acidic, if your total alkalinity is low, around 40 to 60 ppm as is often recommended for a hot tub, then the pH will push down pretty quick. Your TA of 110 ppm is probably about right. Your pH is a little too high at 8.2. You should probably be down to at least 7.8 before using the tub. I try to keep mine around 7.5.

For the "bromine reserve" I used Leslie's Bromide Started 3 TBS.

Also put in Spa Stain Scale 16 oz.  from Natural Chemisty.

Put in 1/4 cup Fresh N Clear Spa Oxidizing Shock.  38% Potassiuum Peroxymonosulfate 62% other ingrediants.

PH is still 8.0-8.2 range.

TA is down to 60

Adding 1.25 oz dry acid now and will check in the AM.

Have 4 tablets of bromine in a floater but getting barely and color on my Taylor drop test.

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On 3/23/2017 at 0:26 PM, arobbert said:

You should read this thread.

 

Still trying to find out what my total TA should be, and wondering how long to let the water sit before retesting.  

TA is at 60 with a 8.0 PH and adding 1.25 oz of dry acid now will check it again in the morning.

 

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19 hours ago, jrspa said:

For the "bromine reserve" I used Leslie's Bromide Started 3 TBS...

You need approximately 30 ppm sodium bromide in the water, which would be 1/2 oz by weight per 100 gallons of water. I'm not sure of the weight of a tablespoon of sodium bromide so you should check to make sure you've put in enough to get the bromide bank up to 30 ppm.

Have 4 tablets of bromine in a floater but getting barely and color on my Taylor drop test.

You need to use an oxidizer, either MPS or bleach, to convert the sodium bromide into bromine (hydrobromus acid). Both types of oxidizer will bring the bromine level up very quickly, within minutes if the water is circulating and the oxidizer fully mixed in. Once you have the bromine level up where it should be, 3 to 6 ppm is recommended, then the tablets will keep the level up over time. But the floater by itself may not get the level up to where it should be, thus you need to use oxidizer first, and also after using the tub to oxidize bather wastes.

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