First summer and never adjusted alkalinity or pH

[hex52]

My pool was completed in August 2018 and since then its chemical levels have been pretty stable. With the weather warming up I noticed some changes. I've been lurking the Pool ABCs here as a guide.

Last month my CYA was about 120ppm so I partially drained and got it down to 85ppm.
I just cleaned my pool this morning, tested with K-2006, then went to the pool store to compare results. They use those fancy testers with the spinning disc.

Here are the results:

Date	Test	FAC	pH	TA	AA	CYA	CC	TAC	CH	Copper	Iron	TDS	Pho	Temp	Saturation Index
2/20	K-2006	9.6	7.7	100		120	0.00	9.60
2/27	Poolwerx	8.8	7.7	68		120	0.00	8.80	292
3/14	K-2006	7.0	7.8	100		120	0.00	7.00						60	0.35
3/28	K-2006	6.6	7.7	110		120								84
4/5	K-2006	5.2	7.8	100			0.00	5.20	420					81	0.5
4/6	K-2006	3.4	7.8	110		85			280					79	0.4	Replaced half the pool water
4/7	K-2006	5.6	7.8	110		75	0.00	5.60						86	0.44
4/18	K-2006	4.6	7.9	115		80	0.00	4.60	280					72	0.45
4/18	Poolwerx	5.2	8.1	104	69	104	0.03	5.23	253	0.2	0		0

My tests were pretty close to theirs. Their treatment recommendation:

1) Alkalinity is low. Add 6lbs. 0.7oz. of Alkalinity Up
2) pH is high. Add 1pts. 15.2oz. of Muriatic Acid
3) Free chlorine is high

My thoughts below
1) Isn't my Alkalinity in the upper range per ABC's of Pool Water Chemistry - Trouble Free Pool
They highlighted the Adjusted alkalinity value of 69 and want me to use this bucket of sodium bicarbonate (baking soda right?). Wouldn't this raise my Total Alkalinity beyond TFP's chart?
2) I agree with this so I will add Muriatic Acid. I've never added any to this pool so I'll dump the 3 cups and run the pump then retest tomorrow.
3) I'm following Chlorine / CYA Chart - Trouble Free Pool and just added another tab to bump it up a bit
4) Is the saturation index chart included with the K-2006 a good indicator of overall quality? Basically staying within the -0.3 and 0.5 range

 

[mknauss]

Stay out of the pool store!

Lower your pH. TA is high so pH will rise.

Your CYA is still high for a non SWCG pool.

 

[mknauss]

Also. Your FC is low for that CYA. Follow FC/CYA chart in pool school.

 

[hex52]

Stay out of the pool store!

I only go to compare tests!

Lower your pH. TA is high so pH will rise.

Should I try to lower TA?

Your CYA is still high for a non SWCG pool.

Then I will partially drain it again when I get a chance.

Also. Your FC is low for that CYA. Follow FC/CYA chart in pool school.

The sunlight and temperature just ramped up here in AZ so I need to start adding more tabs more frequently. I was a couple days behind on maintenance.

 

[scdaren]

The sunlight and temperature just ramped up here in AZ so I need to start adding more tabs more frequently. I was a couple days behind on maintenance.

Gah! No tabs, that's why your CYA is high. Use bleach or liquid chlorine.

Stay out of the pool store!

^ This.

 

[hex52]

Gah! No tabs, that's why your CYA is high. Use bleach or liquid chlorine.

I didn't realize tablets added a significant amount of CYA. I liked the convenience of the automatic feeder, but I will transition to liquid chlorine then.

Will my CYA decrease if I stop using tabs or do I still need to drain?

 

[aeh0603]

If you are using tabs to chlorinate your pool, that is why your CYA is high. All solid/liquid forms of chlorine add something else to your pool too. That something else does not get used up like the chlorine does and will stay in your water until you drain and replace it. The tabs you are using are most likely trichlor which adds CYA (stabalizer) along with FC (chlorine). This is why your CYA level is so high.

Solid chlorine, both tabs and granular, add either CYA or CH to your pool along with the FC, with your high CYA measurement and the fact that you live in AZ and already have hard water with plenty of CH, solid chlorine is not a good choice to use regularly to add FC to your pool. Liquid chlorine is a much better choice if you do not have a SWG (salt water chlorine generator). Liquid chlorine (or bleach, same thing) add water and a tiny bit of salt along with the chlorine. You will need to drain water to lower CH long before you get enough salt build up to even notice it, so liquid chlorine is the best choice for your pool.

 

[mknauss]

Hex -- please read

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.troublefreepool.com

 

[hex52]

If you are using tabs to chlorinate your pool, that is why your CYA is high. All solid/liquid forms of chlorine add something else to your pool too. That something else does not get used up like the chlorine does and will stay in your water until you drain and replace it. The tabs you are using are most likely trichlor which adds CYA (stabalizer) along with FC (chlorine). This is why your CYA level is so high.

Solid chlorine, both tabs and granular, add either CYA or CH to your pool along with the FC, with your high CYA measurement and the fact that you live in AZ and already have hard water with plenty of CH, solid chlorine is not a good choice to use regularly to add FC to your pool. Liquid chlorine is a much better choice if you do not have a SWG (salt water chlorine generator). Liquid chlorine (or bleach, same thing) add water and a tiny bit of salt along with the chlorine. You will need to drain water to lower CH long before you get enough salt build up to even notice it, so liquid chlorine is the best choice for your pool.

Alright I just added about 4 cups of MA I had from last year.

I removed the chlorine tabs and I'm about to head out to pick up some liquid chlorine right now.

When I'm back I'll retest pH and TA, add more MA if necessary to reach 7.0-7.2, then aerate.

As far as CYA goes, that took me all evening to setup the hose to drain into the garage sink, so I'll probably do that in a week.

 

[hex52]

Hex -- please read

How to Chlorinate Your Pool

Before chlorinating your pool, you should know these simple tips. Learn the best way to add chlorine to your pool.

www.troublefreepool.com

Thanks, I never came across this post before. I see the trade offs now and will move to liquid chlorine.

Regarding Saturation Index, is this a useful measurement using the Taylor watergram?

 

[aeh0603]

I didn't realize tablets added a significant amount of CYA. I liked the convenience of the automatic feeder, but I will transition to liquid chlorine then.

Will my CYA decrease if I stop using tabs or do I still need to drain?

CYA does degrade over time and goes down slightly with splash out or if you have to drain due to rain, but these things happen very slowly over long periods of time with the exception of people that live in locations that get tons of rain or need to drain water to close their pool for the winter. In your case it would probably be better to drain water to get your CYA down to a more manageable level.

 

[mknauss]

Regarding Saturation Index, is this a useful measurement using the Taylor watergram?

Use CSI, Calcium Saturation Index as calculated by PoolMath. The LSI is not as accurate for pool water chemistry.

Do you have the Poolmath app?

 

[hex52]

Use CSI, Calcium Saturation Index as calculated by PoolMath. The LSI is not as accurate for pool water chemistry.

Do you have the Poolmath app?

Now I do!

 

[hex52]

I used this from home depot in my last pool. Is this basically "only chlorine"? It says shock on it

 

[mknauss]

That’s good. A little old but ok. See the 19023 on the box? It was bottled Jan 23,2019.

As it warms up, be careful buying HD stuff. It is stored outside and degrades quickly due to heat.

 

[hex52]

It's been just over an hour since I added MA.

TA = 105
pH = 7.6

When can I add more MA to bring it to 7.0?

How I measured TA using K-2006:
- Add 2 drops of 0007
- Add 5 drops of 0008
- Start 0009 dropwise
- At 9 drops it started to transition to red but kind of goes back to green.
- At 10 drops it is a light red / pink
- At 11 drops it's red (any more drops result in the same color)

Because 10 drops wasn't quite red, I figure the measurement was between 10 and 11.
Is this correct?

 

[mknauss]

You go into until the next drop does not create a color change, then subtract the last drop.
See Test Kit Directions

Wait until your pH rises to 7.8. Then add acid to lower it to 7.4. With our fill water you will be doing this all summer.

 

[hex52]

You go into until the next drop does not create a color change, then subtract the last drop.
See Test Kit Directions

Wait until your pH rises to 7.8. Then add acid to lower it to 7.4. With our fill water you will be doing this all summer.

I was at pH 7.8 (K-2006) or 8.1 (Spintouch) earlier this afternoon. I added 4 cups of MA per step 1 in Lower Total Alkalinity - Trouble Free Pool

Are you saying I should only add MA when the pH is at 7.8?

I want to lower TA too and was thinking I should bring pH to 7.0 then aerate.

 

[mknauss]

Your TA is not all that high. Just bring it down with regular maintenance of the pH. Your fill water will push TA up too. So expect to add acid at least twice a week all summer.

 

[hex52]

Your TA is not all that high

Lower your pH. TA is high so pH will rise.

Ok I was reading too much into your previous statement. I understand now... TA is up, but within range, therefore doesn't need to be lowered.

I just added the liquid chlorine and will test in a bit.

By the way this PoolMath app is great! Just subscribed so I can share it here, but it looks like that is only via a link. Can I share my my log contents within a post?