balancing help, please

[padlnjones]

hi,

 

Long time spa owner, just now trying to become a spa water magician...Using a Taylor 2005 kit.

I have a new 340 gal spa, put in fresh water 3 weeks ago.  The Taylor Watergram result was +.08, so I think I did good initially.

 

Lately, I have been trying to more closely balance the TA and pH.  raising the TA made the pH too high, and I have been yoyoing a little with the pH down, and sodium bicarb.

 

tested this morning and showed a TA of 65, and a pH of 7.6-7.7ish.... before I do anything more I would like to consult the oracles  here for advice.  I have read most of what I could find online about the subject, some of which is contradictory.  specifically, is there a way to bump the  TA up near 100, but not raise the pH at the same time?  My thought is to try to lower the pH more first, while the TA buffering is low, so the pH will have more room to rise when the TA is adjusted up.

 

I have read that using the air will cause a greater pH rise, and I use it with the therapy jets.  Also, our tub has microsilk, which is air bubbles to the max.  I haven't seen anything specifically about microsilk and pH, but does anyone have any thoughts on that?

 

I have the Frog inline chlorine system, as well...

 

really trying to dial it in to eliminate  any spousal skin issues...

 

thanks for any suggestions!

 

[RDspaguy]

Been getting alot of this lately. This is copied from another thread I posted in. It is my recommended system to all of my customers and what I do in my own spa.

Fill spa. Test alkalinity.

Balance alkalinity to 80 to 120ppm , 100 being ideal.

After alkalinity is adjusted and stable, at least 24 hours, test ph.

Adjust ph 7.4 to 7.6.

You should not have a chlorine or bromine reading in your spa except right after you add chlorine. Which should only be dichlor. Do not add liquid chlorine or any type of tablet. You are not concerned with what that reading is for now. 3-5 ppm is health dept requirement for PUBLIC spa. Unless you have constant use by everyone in the neighborhood, YOU DO NOT NEED THIS, it is only causing problems.

Add 4 tsp of dichlor only AFTER ALK AND PH ARE BALANCED. 

Use it and enjoy. After each use add 1tsp plus 1/2 tsp per person in the spa of dichlor. Leave cover open for 30 minutes after to help prolong your cover life.

Once each week check alk and ph, balance asneeded. Check free cl and total cl, and shock as needed with 4tsp dichlor. If free cl and total cl are the same or zero, you do not need to shock. This will be most of the time. If you have ozone you will not need to shock.

You may add the nature 2 stick whenever youchoose. I would leave it out for now to help eliminate it as a source for your discomfort.

Rinse filters monthly. Clean them throughly every 3 to 6 months. Drain and refill yearly.

Do not use other chemicals. Scents, mps, conditioner, ph stabilizer, foam remover, none! 

To avoid foaming, do not wash your suit in soap and fabric softener. Do not get oil, lotion, hair conditioner or makeup in the water.

Hard water, meaning high calcium, is not feasible to reduce. Keep your alkalinity where it belongs and your hard water will not be a problem. If alk is high, calcium will come out of solution causing asandpaper feel and white staining in your tub.

A "clean cycle" just moves water through the filter and runs your ozone if you have it. It is meaningless to your spa maintenance. Filtercycles are what count. You want at least 2 hours twice per day minimum! Run a clean cycle afteryou add chemicals or before use if you like.

The 58% dichlor is 42% potassium monopersulfate, or mps. This has a high ph and can give you bad test readings for some time. I would just use the straight dichlor. It is ph neutral and will make keeping your balance a breeze.

[dlleno]

one thing I have discovered is that actively targeting a certain level of TA is not really fruitful.  especially in an acrylic spa you can drop the saturation index below zero without the sky falling.  seriously I test TA from time to time but frankly TA by itself is not a parameter to target.  some may find it helpful in water balance, but there is no merit in chasing a particular TA number.  In fact, you have already discovered that raising TA will cause upward pH drift.  if you target pH instead of TA you will learn that TA can drop below the recommended numbers and the sky will not fall.  Especially if you use the "dichlor switch to bleach" method - -sodium hypo is net pH positive so you may find yourself fighting a loosing battle if you target a certain value for TA.  its better to use dry acid to bring pH down and let TA fall where it may (just watch to make sure it doesn't get too low).  I have operated my spa at TA=50ppm quite successfully --  not because I targeted 50ppm but because thats what it took to control pH.  nothing against those who are successful with higher TA values;  I just found that I can control upward pH drift much easier if I let TA naturally fall below the magic recommended numbers.  yes I test TA because if it goes below 50ppm then I risk a precipitous drop in pH.   

*high TA causes upward pH drift

* dry acid lowers both TA and pH

* agitation raises pH

my source water has fairly high TA so for the first few weeks into a new fill I'm constantly pushing down on pH by adding dry acid.  I just let TA fall.  

[padlnjones]

Hi, thanks for the reply... 

I am trying to walk that fine line between obsessive compulsion, and paranoia... I still have issues with my pH rising after tub use, so I guess it is the agitation from the jets, or worse if I add the air to the jets.  Please correct me if I am wrong, but if TA acts as a buffer for pH, wouldn't pH be more responsive to sodium bisulfate if the TA is lower rather than higher?  And is it correct that sodium bicarbonate will have a greater effect raising TA than raising pH?  I see recommended TA levels of 80-120. 

I have been dropping the pH from 8ish to about 7.2 with 1 TBL dry acid, then raising the TA to 80-100 with sodium bicarb, which puts the pH at 7.5, but it doesnt last if I use the tub...

[dlleno]

pH drift is nearly always a problem in Spas, due to (1) agitation, and (2) heat.  I too was once a number-chaser, but I soon learned that you will be forever chasing your tail if you try and target a certain TA number -- especially if you try to raise TA.  its just not worth the effort.    It's true that TA acts as a pH buffer in that bisulfate has more influence over pH when TA is low. that by itself is not incorrect.  But to say that bicarb has a greater effect on TA than pH I think that is misleading in a spa because of the agitation and water temperature.  i mean people have been successful targeting a certain TA number but I'm not one of them :-).   Higher TA values in a spa result in a greater pH drift, due to agitation and temperature.  A better pH buffer would be to try the Borate solution, which works better to stabilize pH.  

In the end - your goal in an acrylic portable spa with jets, maybe an ozone generator,  and 103 degree water is to control pH upward drift, and you will find that the influence of those factors is less when TA is low.  So.... what I learned is not to target a TA number -- let it drop as  you add bisulfate to drop pH. your skin doesn't care about TA but it does care about pH (as does chlorine), so I have just found that the way around this circus is (1) target a higher pH value than, such as 7.8, and (2) keep beating down your pH and let TA drop as a result.  just keep testing TA so that you don't go too low.  I let mine go as low as 40ppm!  thats kinda scary though -- because as you rightly imply with TA that low you risk a precipitous drop in pH "through the floor".

 

[RDspaguy]

Good to have a chemical guru around. Most of us that respond here are repairmen, and much happier talking pumps and heaters. I know what works well with the water in my area, but not all water is the same. Welcome back dlleno. Glad you are here.

[dlleno]

Thanks RD im pretty sporadic in my attendance lol but glad to help.  

There is one other detail in this area that I should note.   Test pH when water is still/calm. 

  A fun experiment is to test your water "at rest" and then turn on the jet pumps  and open up the air valves.   Then test the agitated water while everything is running.  You'll get a different answer when the two measurements are 60 seconds apart.   The moral of the story is that damage to equipment can occur if pH goes too low and this occurs when the water is still.  Yet your skin will be irritated with high pH and that occurs while you're in the spa not testing it!