Ta High, Ph Low - Seems To Be Against The Norm

[Gouie]

I'm trying to wrap my head around the TA/PH relationship and believe I understand, but I'm running into a continuous problem that seems to be against the norm of others here. I am slowing loosing PH, having to add almost daily while my TA is consistantly high; in the 160 - 180 range. I must be missing something but can't seen to figure it out.

[chem geek]

Are you using a net acidic source of chlorine such as Dichlor or Trichlor or are you using bromine tabs or non-chlorine shock (MPS)? Any of these will tend to lower pH and will also lower TA slowly over time.

[waterbear]

I am slowing loosing PH, having to add almost daily while my TA is consistantly high; in the 160 - 180 range. I must be missing something but can't seen to figure it out.

What are you adding to raise pH?

IF you are using pH increaser (sodium carbonate) be aware that it will also cause a LARGE increase in TA! I would be be better to use borax or, given your high TA, aeration to bring up the pH. A more important question is why is your pH dropping so much and so fast. What sanitizer are you using (and if it is chlorine, what form) and how are you testing your water? If you are using strips be aware that your test results are very possibly bogus.

With a TA as high as yours (if it is really that high) your pH would not be dropping daily unless a large amount of acid of some sort was being introduced into the water since the aeration of the jets would cause CO2 to outgas and pH to rise. If you are using strips to test I would have to make an educated guess that your TA is not that high or your pH is not as low as you think.

[Gouie]

You are correct, I am using test strips. I am using pH increaser to bring the level up. I will give the aeration a try, going to have to do some digging as I have no idea what borax even is. As far as the sanitizer is concerned, I am using chlorine in a granular form not liquid. Having said that the pucks do a very good job of maintaining and rarely do I have to add any in addition.

I understand that drop testing is the preferred method but it is quite time consuming to do on a daily basis when temps during the winter months hover around taht -20C mark. Although not 100% accurate, are strips really that far off?

[waterbear]

I understand that drop testing is the preferred method but it is quite time consuming to do on a daily basis when temps during the winter months hover around taht -20C mark. Although not 100% accurate, are strips really that far off?

Yes. Strips are pretty much next to useless for anything except a quick check on whether there is chlorine (or bromine) present or not (and for that matter, an inexpensive 2 way OTO test kit is just about as fast, more precise, and a whole lot less money to use for a quick daily check on chlorine and pH! Only downside is that OTO only tests total chlorine (or bromine, which is all you need to test for with bromine) so you still need to monitor FC and CC as least weekly if it is a chlorine spa.)

As far as testing in cold weather, you would test indoors and not by the spa. Just collect a sample in a plastic bottle (I use a bleach applicator from the beauty supply since the tip allows me to dispense the amount of water I need easily), carry it indoors where it is warm, and test.

You are correct, I am using test strips. I am using pH increaser to bring the level up. I will give the aeration a try, going to have to do some digging as I have no idea what borax even is. As far as the sanitizer is concerned, I am using chlorine in a granular form not liquid. Having said that the pucks do a very good job of maintaining and rarely do I have to add any in addition.

First concern. Pucks. I assume they are chlorine and not bromine which would mean they are trichlor and VERY acidc (pH of close to 2 when they are added and the chemical reaction when chlorine sanitizes is also acidic so the outcome is extremely acidic) and NOT a good idea in a spa (because of he small water volume and the fact that they dissolve very fast in hot water temperatures, unlike when used in swimming pools).

Borax is sodium tetraborate and is usually found in the laundry aisle of the grocery as 20 Mule Team Borax here in the US. I believe you are in Canada based on your IP address.

Your granular chlorine can be one of three things:

Dichlor, a stabilized chlorine that also causes CYA to rise, It is somewhat acidic, both on addition with a pH around 6 and then the acidic reaction when the chlorine sanitizes, but not nearly as much as trichlor tabs.

Calcium Hypochlorite, an unstabilized chlorine that will also raise calcium hardness. It is basically pH neutral on use (alkaline when it goes in but the reaction of the hypochlorous acid in the water when it sanitizes is acidic for a net neutral pH).

Lithium Hypochlorite, an unstabilized chlorine that has no negative side effects (much like bleach or sodium hypochlorite) other than its EXTREMELY HIGH PRICE. It is basically pH neutral on use (alkaline when it goes in but the reaction of the hypochlorous acid in the water when it sanitizes is acidic for a net neutral pH).

Second concern, test strips. Pretty much useless for water balancing.