The two most popular chemicals available to help you lower the Total Alkalinity in your hot tub are muriatic acid and sodium bisulfate (also known as dry acid). After you’ve added muriatic acid, dry acid or another alkalinity decreaser product, be sure to check the pH level in the hot tub, as the pH level may have dropped as well. I know it seems like a lot of muriatic acid to use to get the TA down but if done properly it will get the alkalinity in range without touching the pool pH level too much. You can go to the swimming pool total alkalinity link to learn how to do that.
The problem with lowering Total Alkalinity (TA) in general is that when you add acid to lower TA, pH also decreases. This limits the amount you can lower TA without pH becoming too low. However, there is something you can do to raise pH that leaves TA alone, Aeration. Aeration is the process of turning on all the jets and air features in your tub, in order to pump as much air into the water as possible.
By adding Acid and Aerating you can lower TA, while keeping pH the same. I won't get into detail why you would want to do this here, but I will say this. The key to a balanced tub is, you should NOT try to adjust pH directly.
Instead, you should focus on Tuning TA to an ideal level, in order to keep pH in an ideal range.This method is a slight variation to the Acid/Aeration method. The main problem with the old method is that it's difficult to know how much acid to add each time. The amount of acid it takes to lower pH to 7.0 will vary a lot depending on the TA. Also, if you have a very high TA (300 ppm), it can take a long time to lower it if only small amounts of acid are added. So, I decided to refine the method a little.
If done correctly, you can lower TA quickly, without pH ever dropping below 7.0.The first thing to remember is, the amount that TA decreases is directly proportional to the amount of acid you add. That is, in a 350 gal tub, 8 oz of Dry Acid will lower TA by 100ppm. It is important to know (by calculating) how much Total Acid you need to add to your tub in order to get to your Target TA. The second (key) thing to remember is, the higher your TA, the less effect acid will have on your pH. If your TA is really high (300), adding acid won't effect pH much at all. This confuses beginners (and some experts alike), which causes them to take much longer to lower TA, or give up altogether.
Because of this key point, you need to add more acid in the beginning, and less as you get closer to your Target TA.So, here is the process.1. Turn on all your jets and air features and keep them on the entire process.
Check starting TA/pH.3. If pH is 1 cup nor Target and pH is 7.8, goto step 48 If TA Target and pH is Target and you can't get pH 7.8 via aeration, Target too low. Stop here.10 If TA = Target and pH is 7.8, Target too high. Lower Target TA and goto step 4.Example:Your TA is 300ppm, you want to lower it to 60ppm, in a 350 gal tub.To lower TA by 240 ppm you need to add a total of 2.4 cups (19oz) Dry Acid.Turn jets/air on.Add 1 cup acid and Aerate 30mins.Check TA/pH. TA=200 and pH8.0Add 6 oz acid and Aerate 30mins.Check TA/pH. TA=125 and pH8.0Add 3 oz acid and Aerate 30mins.Check TA/pH.
TA=90 and pH8.0Add 2 oz acid and Aerate 30minsCheck TA/pH. TA=65 and pH=7.8Add 1 TBS acid and Aerate 30minsCheck TA/pH.
TA=60 and pH=7.6Again, the main thing to remember is, you add more acid in the beginning of the process, and taper off toward the end. This method will allow you to lower your TA in just a few hours, regardless of how high your TA is, without pH ever dropping too low.Lastly, safety is priority one. Be careful with any type of acid, especially Muriatic. If you're using Muriatic acid, wear rubber gloves and eye protection.
![]()
Muriatic Acid is nasty stuff. Dilute all acid in a bucket of water and slowly pour mixure over a return flow, or middle of tub. Be careful not to splash. Turn the Air off when adding if necassary. When mixing Acid and Water, always add Acid to water! NEVER ADD WATER TO ACID!!!Happy Tubbing! IF you have an acid demand test there is an even faster way.Determine the total amount of acid needed to lower TADetermine how much acid is needed to drop your pH to 6.8 or 7.0 (depending on your testkit) and not any lower and add it, turn on aeration and leave it on.in thirty minutes repeat acid demand and add full amount of acid needed to drop ph to 6.8 or 7.0Do this until the entire amount of acid needed to lower TA by desired amount has been added and then just continue aeration until pH is where you want it.
This is an interesting variation on the basic method. I was a little concerned about how low the pH might get with the method, so I ran some calculations using the pH 7.6 starting point and various starting TA levels and the 'half the remaining acid' (ignoring the 1 cup. Richard,Aeration must have an extreme effect on raising pH when it's. If you think about it, if you tell someone to add enough acid to lower pH to 6.8-7.0, considering aeration, that might turn out to be more than this method. The only reason I'm purposing this method, is so you know exactly how much acid to add each time. I see a lot of users try to lower pH, but have know idea how much to add.Also, Richard, I see you're using a target of 50 ppm TA.
I wouldn't recommend anyone lower their TA that low to begin with. That might be too low for some tubs, especially if using Dichlor. If you use 60 ppm TA, what do the pH values come to?
Total Alkalinity acts like a buffer for your PH level in thespa, if your alkalinity is too high your pH is also probably toohigh. These acid levels can affect the feel of the water which canirritate the skin and the eyes. It is not harmful but should beadjusted using a chemical like PH down (sodium bi-sulfate).The real problem with Alkalinity being too high is that this canaffect how well the chlorine is sanitizing the water, the higherthe PH and Alkalinity the less effective the chlorine or bromine iswhich leads to your water not being properly sanitized.Also remember when adding PH down to lower your Alkalinity youshould stay out of the hot tub for a few hows as that is a granularacic that your are adding and you want to give it time to dissolveinto the water.-Jay BroyerPrecision Pool Construction.
Comments are closed.
|
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |