Have issue with very low pH and extremely high alkalinity

[xtexan86]

Hi all, my pH is extremely low...very, very yellow in the test tube and my alkalinity is extremely high as it changes from blue to yellow instead of green to red. I saw in another forum to add 20 Mule Team Borax as this would raise the oH with a minimal rise in alkalinity but I don't think that's really going to help me. Yes, I have been using tri-chloride tablets but since my pool is very small (2,000 gallons) I only put in half a tablet and then still have to brush off algae about 2 times a week. Are the tablets really contributing that much to drive the pH down? I was using liquid chlorine but seems like I had to add that about 3 times a week or more...is that normal? Anyway, I was also seeing some plaster scaling develop a couple of months ago and that seemed to diminish when I added more Muriatic acid. Additionally, my calcium hardness is very high also, somewhere around 500-600. Other than draining the pool at least half-way, does anyone have any suggestions in order to try and level out these readings?

 

[mknauss]

Please post a full set of test results from your own test kit.

 

[Jimrahbe]

86,

The reason your pH is low is because you are using chlorine pucks which contain acid.

Chlorine pucks also contain CYA, and my guess is that your CYA is through the roof high, and that is why you have algae.

That said, without actual test data, I'm just guessing. Show us the following readings:

FC
CC
pH
TA
CH
CYA

Thanks,

Jim R.

 

[mgtfp]

The TA test turning yellow is not a sign of high TA but a sign of the indicator dye reacting with high chlorine, which can be mitigated by using more Thiosulfate. As Jim already said, I also suspect that you have very high CYA, so that even high chlorine levels can't kill your algae.

 

[xtexan86]

The TA test turning yellow is not a sign of high TA but a sign of the indicator dye reacting with high chlorine, which can be mitigated by using more Thiosulfate. As Jim already said, I also suspect that you have very high CYA, so that even high chlorine levels can't kill your algae.

I will try and get a set of readings tomorrow, but my pH and Alkalinity were off the scale today, the Calcium hardness was the only one I came close at and even that one I quit trying to get an exact reading after I surpassed 500. I didn't try a CC or TC test as I try not to keep more than 1/2 puck so really didn't consider that my chlorine would be so high as to affect the alk test. Should I add some baking soda to try and bring up the pH and then test?

 

[SoDel]

If FC is super high, doesn’t that cause the pH test to be inaccurate?

I think you’re poking at the bear instead of trying to trap it. Don’t just start adding stuff. Post full test results so someone can give you a plan of action.

 

[mgtfp]

If FC is super high, doesn’t that cause the pH test to be inaccurate?

I think you’re poking at the bear instead of trying to trap it. Don’t just start adding stuff. Post full test results so someone can give you a plan of action.

What happens at high FC, is that phenol red turns into chlorphenol red, which changes from yellow to red at lower pH than phenol red does. At normal pool pH this means that it is basically always red, but at very low pH, chlorphenol red shoes up yellow.

So, the TA test turning yellow and the pH test showing yellow I interpret as FC being high and pH being low. Very low.

 

[mgtfp]

Should I add some baking soda to try and bring up the pH and then test?

I'd suggest to run the TA test first with one or two extra drops of R-0007 (Thiosulfate) to remove the chlorine interference. I suspect that your TA is very low and pH probably close to 4.5.

Half a 3 inch Trichlor puck, which should have about 4 ounces, raises the FC in a 2k gal pool by about 14ppm and CYA by about 8.3ppm.

With a 2k pool with probably sky high CYA (would be good to get that confirmed), I'm wondering if a drain-refill would be the most efficient way forward.

 

[xtexan86]

I'd suggest to run the TA test first with one or two extra drops of R-0007 (Thiosulfate) to remove the chlorine interference. I suspect that your TA is very low and pH probably close to 4.5.

Half a 3 inch Trichlor puck, which should have about 4 ounces, raises the FC in a 2k gal pool by about 14ppm and CYA by about 8.3ppm.

With a 2k pool with probably sky high CYA (would be good to get that confirmed), I'm wondering if a drain-refill would be the most efficient way forward.

Here are the test results from this morning.

FC 7.5/5.5 Did 2 tests TC 5.5 both tests
CC 0 or -2
pH Off the charts, took 20 drops of R-0006 to bring it up to 7.4
TA On the 25mL test I added 2 extra drops of R-0007 and came up with about 75, on the 10mL test I added one extra drop and came up with 80
CH At least 500-600, color doesn't really change to blue, more like a very clear barely bluish-tint
CYA Also off the charts, can't see the dot anymore when liquid reaches the 1.5mL level in the small tube

 

[Jimrahbe]

86,

The only way to fix your CYA problem is with a drain and refill. No sense screwing with anything else until that get done.

The only good news is that the size of your pool should make that easy to do.

Thanks,

Jim R.

 

[Bperry]

Here are the test results from this morning.

FC 7.5/5.5 Did 2 tests TC 5.5 both tests
CC 0 or -2
pH Off the charts, took 20 drops of R-0006 to bring it up to 7.4
TA On the 25mL test I added 2 extra drops of R-0007 and came up with about 75, on the 10mL test I added one extra drop and came up with 80
CH At least 500-600, color doesn't really change to blue, more like a very clear barely bluish-tint
CYA Also off the charts, can't see the dot anymore when liquid reaches the 1.5mL level in the small tube

For future reference on FC, CC, and TC…The measurement you get with the powder and drops is FC. Then when you test for CC, you add 5 drops of the reagent to make the same sample pink again, and then count how many drops or original reagent to go clear again.

The TC is just the sum of FC and CC. So it’s impossible for the FC to be higher than the TC. Just observing that you may have a typo or testing error. It also means you don’t have to test using the yellow OTO chlorine test.

 

[xtexan86]

For future reference on FC, CC, and TC…The measurement you get with the powder and drops is FC. Then when you test for CC, you add 5 drops of the reagent to make the same sample pink again, and then count how many drops or original reagent to go clear again.

The TC is just the sum of FC and CC. So it’s impossible for the FC to be higher than the TC. Just observing that you may have a typo or testing error. It also means you don’t have to test using the yellow OTO chlorine test.

The instructions for my DPD test don't include a "powder" nor does it ask to count any reagent drops and observe the sample going clear. The card calls for 5 drops of R-0001 and R-0002 to be added to 9mL of pool water. The color scale comparison on the back of the plastic test tube is noted as "free chlorine." Then 5 drops of R-0003 is added and after color comparison (again off of color scale on test tube), this is "total chlorine." Instructions then say subtract FC from TC and record as CC. "Formula TC - FC = CC. Please tell me where the typo is here.

 

[xtexan86]

86,

The only way to fix your CYA problem is with a drain and refill. No sense screwing with anything else until that get done.

The only good news is that the size of your pool should make that easy to do.

Thanks,

Jim R.

Thinking that's the only thing to do also. 2 questions...Would draining just half maybe be enough to stabilize readings? Also, what amount of liquid chlorine should I be adding? I have no idea how to compare the portion of a chlorine puck to liquid. Thanks!

 

[Jimrahbe]

86,

Since you don't actually know what your CYA level is, it is impossible to know if draining it halfway will be good enough or not.

You want your CYA to be about 30 to 40 ppm in your area.

You can run a diluted CYA test and see what you get.. Here is how. CYA - Cyanuric Acid Test See step #8...

I suggest that after your refill, you add about 20 oz of 8.25% Liquid chlorine and then about 10 oz a day to maintain it.

Thanks,

Jim R.

 

[mgtfp]

The instructions for my DPD test don't include a "powder"

It sounds like you have the K2005 kit and not the K2006. You can just buy refills of R0870 DPD powder, R0871 FAS titrating reagent (I suggest the 2oz C-size) and R-0003 reagent for testing CC (0.75oz A-size is enough). Follow the test instructions here: FAS-DPD Chlorine Test

Also, what amount of liquid chlorine should I be adding?

Use PoolMath to calculate how much of any chemical is required to reach your target levels.

You need to follow the FC/CYA Levels to know the target FC level for a given CYA level.

I'd suggest to read through the Pool Care Basics to get a good overview of the TFP methods and the recommended levels.

 

[xtexan86]

86,

Since you don't actually know what your CYA level is, it is impossible to know if draining it halfway will be good enough or not.

You want your CYA to be about 30 to 40 ppm in your area.

You can run a diluted CYA test and see what you get.. Here is how. CYA - Cyanuric Acid Test See step #8...

I suggest that after your refill, you add about 20 oz of 8.25% Liquid chlorine and then about 10 oz a day to maintain it.

Thanks,

Jim R.

Thanks, that's very helpful. Any idea what causes my CH to rise so much? I'm on my 2nd plaster layer (long story) for this not yet 2 year old pool and each time within about 3-4 months, my CH starts rising as it is only about 140 coming out of the tap. There are times when I use a steel brush to sweep the pool, is that adding calcium from the plaster surface? Also, I did ask a pool guy the other day if dust could be contributing and he didn't think so. We do have some hard water in our area, but not so bad that I have to frequently clean off shower heads, etc. Could the chlorine tablets be adding Ca to the water? Thanks!

 

[xtexan86]

It sounds like you have the K2005 kit and not the K2006. You can just buy refills of R0870 DPD powder, R0871 FAS titrating reagent (I suggest the 2oz C-size) and R-0003 reagent for testing CC (0.75oz A-size is enough). Follow the test instructions here: FAS-DPD Chlorine Test




Use PoolMath to calculate how much of any chemical is required to reach your target levels.

You need to follow the FC/CYA Levels to know the target FC level for a given CYA level.

I'd suggest to read through the Pool Care Basics to get a good overview of the TFP methods and the recommended levels.

So I replaced half of the water...should've done more but here's the newest readings..

FC and CC - both are 10.0
pH 7.0 and only took 6 drops to bring it up to 7.6
TA 100
CH 300
CYA 100

I don't plan on adding any chlorine for a bit. Will anything tend to naturally bring the CYA down? Aeration?

 

[Jimrahbe]

86,

Nothing will reduce CYA except water replacement. That is what I said in post #10 and it is still true.

Sorry, but you still need to get your CYA down to around 30 to 40 ppm.

Thanks,

Jim R.

 

[Bperry]

Thanks, that's very helpful. Any idea what causes my CH to rise so much? I'm on my 2nd plaster layer (long story) for this not yet 2 year old pool and each time within about 3-4 months, my CH starts rising as it is only about 140 coming out of the tap. There are times when I use a steel brush to sweep the pool, is that adding calcium from the plaster surface? Also, I did ask a pool guy the other day if dust could be contributing and he didn't think so. We do have some hard water in our area, but not so bad that I have to frequently clean off shower heads, etc. Could the chlorine tablets be adding Ca to the water? Thanks!

Steel brush can be kinda harsh on plaster, a plastic brush would be better. You’re going to need to keep the chlorine up pretty high with a CYA of 100.

 

[JamesW]

Any idea what causes my CH to rise so much?

Your plaster is dissolving due to the bad chemistry.

You need to keep the chemistry right or you will keep destroying the plaster at a fast pace.

Keep the CSI between -0.3 and 0.0.

Maybe get a SWG.