Low PH problem

[PoolDoc]

Using a lot of trichlor will lower your pH a lot, and as the CYA levels rises, pools often get resident algae that increase chlorine use, and in turn, increase acidity from trichlor.

Do this:
1. Buy 6 boxes of 20 Mule Team borax from Walmart.
2. Test your pH test, by adding a pinch of borax to a pH water sample -- it should go from yellow to purplish.
3. If your test is OK, then start adding borax, 1 box at time, added slowly to the skimmer, with the pump running.
4. Add up to 2 boxes every hour.
5. Continue till the pH is above 7.2.

What you have to understand is that a pH reading of 6.8 does NOT mean your pH is 6.8; it means it's 6.8 or LOWER! It may be 4.9!

As a result, you can add bases (like soda ash or borax) for quite awhile without seeing any change. The pH *is* changing, but YOU can't see it, because your kit doesn't measure that low. Trichlor has a pH around 2.7, so your pool's pH could be VERY low.

You are probably damaging your liner, so you don't want to wait. Add borax till your pH is above 7.2. Period. Don't quit till it's done, no matter how many boxes it takes. If you want to measure how much it will take, the ABD (acid/base demand) test in the K2006 will allow you to measure that.

Meanwhile, you MUST test your CYA level -- I'm guessing it's going to be very high. And that brings a whole other set of issues. Test kit info below.

Ben

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+ Get a cheap OTO (yellow drops) / phenol test kit, or if available at YOUR Walmart (check availability), get the HTH 6-way DROPS test kit, which is compatible with the Taylor K2006. Test the pool as soon and you can, and post the results. If you get the 6-way kit, ALSO test the water you FILL the pool with, especially if it's a well, and post THOSE results as well. (The HTH is the best available kit you're likely to find locally, but it's not the K-2006. It can only provide rough measurements chlorine levels above 5 ppm, and it measures "TOTAL" hardness, rather than "CALCIUM" hardness, which is not ideal.)

+ Having a good test kit makes pool care easier for EVERYONE, but is an ESSENTIAL tool for pools with problems. A good test kit means a kit that can test chlorine from 0 - 25 ppm, pH, alkalinity, calcium hardness, and stabilizer with reasonable accuracy. Test strips (AKA 'guess-strips' ) do NOT meet this standard. Some pool store testing is accurate; most is not. The ONLY way you'll know whether your pool store is accurate or bogus, is by testing accurately your own self. On the other hand, pool store 'computer' dosing recommendations are NEVER trustworthy -- ignore them. They are designed to sell more chemicals than you need, and WILL cause many pool problems.

+ We recommend the Taylor K-2006 test kit, which meets the requirements above, for many reasons. The HTH 6-way drops kit is a great starter kit, and is compatible with the K2006 (it's made by Taylor). There are a few alternatives; for example Lamotte makes an FAS-DPD kit that's OK -- but it costs 3x as much. But, we're not aware of any test that is better, and since we are all familiar with the K-2006 (and can help you with it) we recommend it exclusively ( Test kit info page )

One caution for the 2012 season: Amazon does not stock the kits directly. So when buying at Amazon, Amato is our current preferred seller. However, they often don't list enough stock to last the whole day, so try order mid-morning. You should expect a delivered cost under $60 for the K2006A and under $95 for the K2006C. If you can't find that, wait a day.

+ Here are links to the kits we recommend (you can check local availability on the HTH kit, using the Walmart link):

HTH 6-Way Test Kit @ Walmart
Taylor K2006A (3/4 oz bottles) @ Amazon
Taylor K2006C (2 oz bottles) @ Amazon

[john1261]

I bought the HTH 6-Way Test Kit and checked for Total Hardness >200 if I read it correctly. The sample never turned red but more of a purple to begin with. I put 20 drops of the indicator in and it really didn't change any.

CYA tested well over 100. Not sure what to do about those two issues.

[PoolDoc]

For now, you need to run higher chlorine levels than you can measure with your kit. Keep the chlorine in the DARK yellow to orange-tinted yellow OTO range (10 - 30 ppm). Read the Best Guess page, linked in my signature block, for an explanation and more info. Probably the best way to do it, is to dose to orange-tinted yellow, and let it fall over a period days to dark yellow.

Make sure your pH is below 8.0 BEFORE you dose with chlorine: you cannot test pH with phenol red in the OTO orange range. So only re-test pH just BEFORE re-dosing with chlorine.

You can swim safely and comfortably with these levels, but I wouldn't recommend wearing your newest swimsuits when the pool is at peak chlorine levels. People are far, far more chlorine resistant than swimwear is . . . and the more expensive the suit, the less resistant it is!

But, you're going to need to order a K2006 kit (links in prior post) -- you really can't manage the high hardness levels and high CYA with the kit you've got.

[john1261]

Ben,

I have added 6 boxes of Borax 2 each hour and retested. The PH is now a little darker yellow but still not showing any red. Still less than 7.2. Do I ignore that for now and start adding chlorine? When do I know that I can proceed with whatever is next? Pool water is still clear.

[aylad]

Getting your pH up above 7.0 is critical--keep working with the Borax until the pH comes up--then start working on the chlorine (and I would stop using any trichlor or other stabilized chlorine, and switch to bleach!).

[john1261]

I have already added 12 gallons of bleach to the pool and have the chlorine in the orange tinted yellow range. How do I test PH at that level?

[Watermom]

How do I test PH at that level?

In a nutshell, you can't. That is why it is always a good idea to adjust pH before you shock a pool.