Total Alkalinity=0, yes zero!

Need a little help with this one because I've never seen this before.

My neighbor opened his pool yesterday (24K gal vinyl IG pool, Chlorine). When I tested his water for him I was alarmed. His total Alkalinity was 0, yes zero! I even tested it twice with my Taylor DPD kit to make sure I hadn't done anything wrong. Also his pH was off the scale low, well below 7.0, yellow in color.

The water was a little cloudy with a bit of a green hue, but we could easily see the 8foot deep bottom and of course there was algae growing on the walls and bottom. All pretty normal stuff for opening in mid May.

Now I know from experience pH and TA can be a little whacky when first opening, but I've never seen anything like this before so that's why I'm here.

So at least to get him started yesterday, I had him start with 2 gals of 12.5% CL and he had 5lbs of baking soda left over from last year so I had him add that. I also had him brush and will be retesting everything today, including CL, pH, TA, CYA.

So my questions:
1. Has anyone seen TA go to zero and any thoughts on how/why this would happen?
As a reference point, my pool, virtually the same as his, only saw about a 30 point drop in TA over the winter (from 90 to 60).

2. The pool calculator says about 32lbs of baking soda to go from TA 0 to TA 100. Should I have him add it all at once, or sneak up on it say 10LBs at a time? Should TA=100 even be our target?

3. Should he also get borax to raise his pH or should we wait and see how the baking soda does first before we add too much stuff and perhaps confound the data?

Thanks
Andy

I'm almost fairly certain that your alkinity isn't "0", but your pH test being so low is making it look that way.

I would get the pH up 1st and in a hurry. Get the pH up using Borax (20 mule team) and then measure alk.

TA is a measure of the bicarbonae in the water. When the pH is very low there will be no bicarbonate, it will all be in the form of carbonic acid (CO2 dissolved in water) so what you are seeing is to be expected when the pH is very low and is common when a pool is run on trichlor tabs, which are very acidic (and TA is not monitored weekly).
You want to get the pH up as quickly as possible since very low pH (which this pool certainly has) can damage equipment and vinyl liners. Baking soda is not going to be that effective at raising the pH if it is very low. Get the borax! If your Taylor kit has a base demand test (if you have the K-2005 or K-2006 it will) use that but add twice the amount of borax for the amount of soda ash it says to add. If the demand test is out of range (which it very possibly is) add two boxes slowly through the skimmer and retest after about an hour of circulation. Keep that up until you get a pH reading above 7.0 or until the base demand test brings the pH up above 7.0 in 10 drops or less and consult the treatment table in the booklet that came with your Taylor kit to determine how much soda ash to add and then add twice the amount of borax.

Thanks Waterbear and The Goose. We will focus on the pH rather than TA for my neighbors pool at this point.

My Taylor kit actually has the base demand and acid demand test, I've just never used them because I've never had that problem. Waterbear thanks for mentioning that.

So it took 30 drops to bring the sample to the pH range of 7.4-7.6, so based on what the book says, it says to add about 18-20lbs. Based on what you said to add 2x that amount of borax--- so I've instructed him to add 38 lbs of borax into his 24K gal pool.

Thanks ---will provide updates later.

Waterbear you are correct about the trichlor tablets. He uses them all the time and I told him to stop using them because of the acidity and CYA---his CYA is 80, so I said use no more for the rest of the season. I told him stick with straight liquid CL.

Do NOT have him add 18-20 lbs. of Borax all at once!

Thanks to all that helped on this thread. I got my neighbors pool in order. It took about 40 lbs of borax in 24K gal of water in his vinyl IG pool to get the pH up to about 7.4. The TA is still around 50, so I'm going to have him add more baking soda to get that right.

You are welcome! Now, it is time to go swimming!