Help with high PH

[novice888]

I am new to all of this and have inherited a hot tub with our new house.  It is all fully cleaned and filled up, but I can not seem to balance the PH.

I have bought Jacuzzi PH- as i live in a hard water area and AquaChek is showing a pink high PH.
Despite adding now 3 tablespoons at 3 seperate times last night and today, the PH is still in the pink zone.
Do I just continue?
I have been disolving it in water first before pouring it in.
My weighing scales is out of batteries and thus the reason for the tablespoon method.  I have figures that 11grams is roughly 1 tablespoon

[BullFrogSpasMN]

need to know what your pH & Alk. numbers are right out of the tap...much easier to dial it in if you know what you are working with originally...3 Tablespoons may be close, on the flip side some tubs (depending on water source) will need upwards of 8-16 ounces, just depends on the water source hence the need for "baseline numbers" for both pH and Alk.

[The Wizard of Spas]

Knowing the pH/alkalinity of the source water is key.  Additionally, if you use, say, a total of 16oz (1lb) of reducer to finally get your pH and/or alkalinity in range, note that for the next time you fill the tub.  You can add the total amount to the footwell when you begin to fill the tub and by the time it finishes its first jet cycle the water should be balanced. 

Additionally- I have found that when lowering pH and/or alkalinity, it is most effective when the water is completely calm.  Running the jets is fine, but the most effective way to lower is to have the water completely calm.

I have some customers that require 1-3lbs of reducer from the onset as their source water is high in both pH and alkalinity.  So don't be afraid if you have to add a bunch of reducer when you fill your tub. 

I hope this helps.  Good luck moving forward.

[dlleno]

pH rise in a hot tub is common.   in my experience I find that store recommendations and rules of thumb generally recommend too high of a TA value, and in a hot tub with lots of bubbles and agitation, that leads to pH rise.  The other misconception about spa water that leads to high pH troubles is the assumption that you have to target the saturation index like you do in a pool, and TA values of 80-120.  But in an acrylic spa you can run with a slightly negative "saturation index" without any problem, and typically that means lower calcium and lower TA than you would normally find in a pool.   So don't be afraid to run a lower TA.

finding what works is a matter of experimentation because every soaker is different (skin chemistry).  I have great results with the following approach

1.  target a  higher pH value.  in other words, don't be afraid of 7.8.  get a Taylor test kit and measure pH accurately so that you are never in the dark
2.  dont' be afraid to lower TA below the recommended figures of 80-120.  you can do down as far as 50ppm and that will help with pH rise


in more direct answer to your question, yes you can continue to add pH- (acid) to lower pH but you really need to measure TA (with a Taylor kit) to make sure you don't go below 50.  TA acts as a pH buffer so if it gets too low then you will see wild excursions of pH and especially the risk of a sharp drop in pH which is bad for your equipment. 

Lowering TA comes very naturally in a hot tub because when you add acic (pH-) you lower both pH and TA at the same time.  then when bubbles and jets and ozone and heat cause the pH to rise again  you add more acid and you will again lower TA some more.  thats what you need to watch -- you can continue to lower TA using this method until you reach 50ppm and you really shouldn't go lower than that.