I Can't Get The pH Up In My Pool

by Liz

I Can't Get The pH Up In My Pool

by Liz
(South Africa)

I have recently purchased a house and trying to figure out how to balance the pool. It is a fibreglass pool approx 27,000 litres.

The pH reading is very low, below 6.4 (the tester kit shows the water as bright yellow). I have added 1 x 250g packet of HTH 'pH up' and that didn't work. After a day, I added another packet. It still hasn't worked.

Now I read from other comments that I must read the 'Total Alkalinity' but I don't even have a tester kit for that and this is the bit that confuses me. Is this what I need to do next, what do I need to do it?

Thanks for the question Liz

First thing I would recommend is to stop using anything you buy from the pool store called "pH Up" or "Alkalinity Up". If you look at the ingredients it's probably sodium carbonate, sodium bicarbonate, or something similar. This is nothing more than baking soda (not baking powder) that can be purchased in your local grocery store for 1/3 the price.

Next, I'll need to convert litres and grams into gallons and pounds, then convert back to metric for you. I'm not too familiar with the metric system, as are most Americans.

For every 10,000 gallons, to raise the pH 0.1ppm, you'll use 1.25lbs. of baking soda. This is 567 grams. As you can see you probably didn't use enough.

Without going into all the math about how I converted this, the short answer is you'll need 9.375lbs. of baking soda to bring the pH up to 7.4ppm. This equates to 4252 grams, or 4.25 kg.

This is where persistence and patience comes into play. Many pool owners make an adjustment then test after an hour or two. They normally get a false reading. The reason is you need a full turnover of the water before taking a test and making another correction. This is normally about 8 hours. The water needs to fully circulate
through the entire system before taking another test. This is the "patience" part. Make your adjustment in the evening, with the filter on and any water features such as slides or fountains ON, and test in the morning. Test the water, make another adjustment, then retest in the evening and make another adjustment if needed. It can take a couple of days to raise the pH a full 1 measure, from 6.4 to 7.4.

Start with a 1 kg, or 2 pounds, and work up from there. Don't simply dump all of the bicarb into the pool at once. You may put too much in and overshoot your target of 7.6 - 7.8. Remember to have the filter on when raising the pH.

The total alkalinity (TA) is the opposite side of the same coin of pH and can be raised with sodium bicarb. It's how you put it in the pool that decides whether you want to raise the TA or pH. To raise the pH you'll want to dilute the bicarb in a bucket and broadcast it around the perimeter of the pool with the pump on.

To raise the TA you'll turn the pump OFF, water motionless, and add straight into the pool, no diluting. Leave the pump off for as long as you can, maybe overnight, then turn the pump back on, allow for 1 turnover, then test and make another adjustment if needed.

The TA fill water where I live is 30ppm and the pH is 8.2ppm. Now, how can I use bicarb to raise the TA without the pH going through the roof? I've used the above method to balance the YMCA pool several times and the hundreds of pools I've taken care of. It works, but again, you need patience.

Get a good test kit. I'd encourage you to get a Taylor FAS-DPD K-2006 pool test kit. This is the one I've used since 1999 and most pool professionals use it as well. You can also go to your local pool store and have the water analyzed for free.

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