ph level keeps rising

Kevyn

LifeTime Supporter
Jun 30, 2010
9
Hi...new to the site and this is my first post. I just tested this morning, but didn't write everything down to post. But I do
remember the chlorine level was around 3.0ppm. TA was around 130. But what I don't get is that every few days the ph level
changes. Today it was 7.8, so I had to add a bit of acid. Two hours later everything tested normal. But I just had to add
about a pint of acid two days ago. Is this normal?
 

duraleigh

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Is this normal?
Welcome to the forum. :lol: Yes, it's normal. Most SWG's cause a rise in pH. It doesn't sound like you are using too much so I might suggest just leaving it.

You could let it get to 7.8 if you like and then take it down to 7.2 so you don't have to add so frequently.

You could also drop your TA but that's somewhat more complex. YOu can read how to lower TA in Pool School if you want to tackle it.
 

rsharp

Well-known member
Jun 12, 2010
129
its probably your Alkalinity. when your Alk. gets low your ph tends to go up and down. when your Alk. gets high your Ph tends to drift upwards...
i try to keep my Alk. around 85
 

duraleigh

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its probably your Alkalinity. when your Alk. gets low your ph tends to go up and down.
Well, yes and no. SWG's will almost always cause pH rise in a pool.

OP was not particularly clear but doesn't seem to indicate pH is going up and down...only raising. Also, TA of 130 is not low....if anything, it is a little too high for an SWG pool.

Because OP so far is demonstrating minimal acid usage, I am suggesting he do nothing. If acid consumption becomes much greater or OP is bothered by the frequency with which he has to add acid, then lowering the TA down around 70 will probably help. Directions for permanently lowering TA can be found in Pool School.
 

Kevyn

LifeTime Supporter
Jun 30, 2010
9
Thanks for the replies. I used a pint of acid this morning and about four hours later
had several people swimming for most of the day. Tested just about an hour ago
and the CL lowered to around 2.0, ph lowered to 7.6 and TA tested at 110ppm.
So seems to me that everything is spot on. As far as the ph levels are concerned,
they're not going up and down. The level always goes up and then I have to use a little
acid to bring it back down. Never have had a test where the ph level dropped.

My pool is not shaded at all. It gets full sun all day. And today was a hot one, and
tomorrow will be too. So the CL level that was a bit high this morning dropped. I
usually have to keep the SWG at 80% to maintain around a 1.5-2.0 CL level. Our
project engineer said after filling the pool we'd probably never have to raise the SWG
above 40%, boy was he wrong. I've only had to use shock once, and that was after
three days of running at 40%. So I bumped the SWG up to 60%. It got better, but
never did keep the CL up where it should be. After leaving it set to 80%, I haven't had
any problems. Our temps have been in the mid to high 90's. Tomorrow it suppose
to be 99. So I run the pump around ten hours a day, 11am-9pm.

Thanks again for your help.
 

duraleigh

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Hey, Kevyn,

I'll bet we can help you get that SWG turned down.....what is your CYA (stabilizer) test result?
 

Richard320

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Jan 6, 2010
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Sounds normal to me. My pool is smaller than yours, no SWG, and I use about that much acid. I get a lot of aeration from circulating water in the spa, and I have really hard fill water.
 

Kevyn

LifeTime Supporter
Jun 30, 2010
9
Here are my test results with the CYA.

FC 3.5
CC 3.0
Ph 7.2
TA 120
CH 250
CYA 50
 

Kevyn

LifeTime Supporter
Jun 30, 2010
9
Well let me start all over. Evidently I may have mis-read something. Yesterday I had to use some shock
and a little acid. I noticed that I had some dark mustard colored junk on the bottom of the pool. And I'm
pretty sure it wasn't sand or any kind of sediment. So it must be algae. It appeared to be a little spongy
looking. I'm having to use two different test kits since just one doesn't cover the six tests I need to post.
The first kit (which are strips) and using it's terminology covers total hardness which I assume is CH, then
total chlorine which I assume is CC, then free chlorine, Ph, TA, and CYA. The other kit uses reagent bottles.
It covers FC, Ph, and TA. But it also tests for acid demand. After adding shock yesterday around 9am the
pump ran up to 9pm last night. This morning I noticed just a very small amount of the same junk on the
bottom near the deep end. Here are the test results I took this morning before the pump came on using
both kits. The kit with six tests shows total hardness 250, total chlorine 1, free chlorine 3, Ph 7.6, TA 120,
stabilizer 0.

The other kit results were free chlorine 3.0, Ph 7.2, TA 100. And of course no acid was needed. In my very
uneducated opinion I think my problem is that for the last week we've had very high temps and bright
sunshine all day everyday. And our pool has no shade at all. So much of the FC is being eaten up by sunlight.
Especially since I have little or no CYA. Yesterday the CYA measured 50. This morning it's 0. And since I use
a SWG my Ph levels will creep up and I'll have to add about a pint of acid every two or three days to get it
back to a normal range. I do intend on purchasing the test kit promoted in this forum. So based on what I've
posted what should I do? Thanks....
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
CC is not Total Clorine, CC + FC = Total Chorine. You say you might be seeing what appears to be algae in the pool and your previous post pointed to a CC level of 3.0. The number you list for Total Chlorine of 1 does not make sense when you say your Free Chlorine is 3. We really need to have a CC (Combined Chlorine) test done to see if you indeed have organics in the water. Take a look at the instructions on your test and ensure that the number you are listing a 1 for Total Chlorine is not in fact Combined Chorine (CC).
 

duraleigh

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Kevyn,

Of course, I have some self-interest here but this quote points out why we emphasize the use of a quality test kit.
Yesterday the CYA measured 50. This morning it's 0.
CYA doesn't go away. But testing errors like that simply cause you (and the forum) to spin your wheels trying to get you water clear.

Purchase either the K-2006 or the TF-100 and you understand how easy it is to manage your pool and stay out of the pool store. :lol:
 

Kevyn

LifeTime Supporter
Jun 30, 2010
9
Ok...just did another test minutes ago. Pumps been running for 2.5 hours. Water is crystal
clear. Deep end is 8' and I can see the screw heads on the two main drains. The six way
strip kit is made by aqua chem. I followed the directions exactly. So maybe it's a flawed
kit. Anyway...total hardness 250, total chlorine 1, free chlorine 3, Ph above 7.2-below 7.8,
TA 120, CYA 0.

Reagent kit made by Pentair..."chlorine residual" above 1.5-below 3.0. Ph above 7.2-below 7.6.
TA 110. Other than acid demand it only tests those three.

I say above and below since there were no in between numbers. And I'm using the name for
each test according to what's actually listed on the test kit. So obviously I need a better
test kit.
 

zea3

Mod Squad
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Jul 10, 2009
10,968
Houston, Texas
Are the CYA results coming from test strips?

When starting a SWG it helps to raise the FC to shock level with liquid chlorine until you pass the overnight test to make sure you are starting with sanitized water, then turn on the SWG to keep the FC at your recommended level. You may have to play with the % and run times to find what works best for you.

SWGs are great for maintaining FC levels but they take a while to build up to recommended levels by themselves, so the liquid chlorine keeps things in check until the SWG catches up.
 

benavidescj

LifeTime Supporter
Apr 27, 2010
431
Fleming Island, FL
Total Chlorine is Free Chlorine plus Combined Chlorine or TC = FC + CC. If your Total Chlorine is 1 and your Free Chorine is 3 then your Combined Chorine would have to be a negative number which does not make sense. You should get a better test kit like the TF100. This test kit uses titration which is better than trying to match colors on a test strip.
 

Kevyn

LifeTime Supporter
Jun 30, 2010
9
The CYA is from the test strip. The kit from Pentair doesn't test for CYA.

And yes...I just ordered the TF100 kit. But my actions were backasswards. I ordered
the kit and then became a TFP supporter. Didn't know there was a discount for
supporters...my bad.
 

Ohm_Boy

TFP Expert
May 1, 2007
1,344
Orlando, FL
If you take measurements with different kits, expect different results.
Test strips are notoriously inaccurate, regardless of how well you perform the test. A good drop-based CYA test is +- 10, but strips can to be plus or minus Wisconsin.
You would benefit from a good test kit with a FAS-DPD chlorine test. Then you could really know your CYA level, and adjust your chlorine level properly to attain a shock level for your pool, and be able to tell what you are losing to organic oxidation.
 

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