can muriatic acid and baking soda be added to pool at the same time?

[JamesW]

When you're going from a high TA to a lower level, then you shoot for a 7.2 ph. As you close in on the optimal TA, then you begin to choose a higher ph target. Since you're getting close to a good TA, I would suggest lowering the ph to about 7.7 as needed.

With tabs, your ph should not rise too much because the tabs are acidic. Also, monitor your CYA to make sure that it does not get too high.

 

[Marcion333]

yesterday pH was 7.4 and TA was 80. nothing put in pool.
today (1/2) pH was 7.7 and TA was 70. i put 3 cups acid into pool.

 

[JamesW]

Unless the ph is over 7.8, I would leave it alone.

Can you post all water chemistry, including water temperature?

 

[Marcion333]

today 1/3 water temp is 47°, FC 3.5, CC 0, pH 7.5, TA 60. nothing added today. the last calcium hardness was 190. later today i'll take a CYA level.

 

[JamesW]

I would suggest raising the calcium level and switching to liquid chlorine. I would try to keep the ph at about 7.8.

As much as possible, try to find your pool's natural balance points. When you do, you will find that you don't have to adjust the chemistry very much at all.

One of the things people do initially is to fight the natural balance points and spending too much time adjusting things.

 

[Marcion333]

i haven't tested CYA yet, i had to work on the only sunny day we've had in DFW, and i understand this test should be done in sunlight but test and front of body facing away from sun.
yesterday —1/4— FC 3.5 pH 7.7 TA 60, nothing added. so far so good although pool guy thinks TA is too low of course.

today 1/5 FC 3.5, pH 7.7, TA 60, CYA level 40. nothing added. yipee!

CSI = -0.5.

 

[Marcion333]

by the way, before i did the CYA test, i warmed up the water sample in my pocket. i hope this was the right thing to do.

 

[JamesW]

If you raised the TA, the ph would jump up again and then you would have to add acid, which would lower the ph and TA. It's an endless cycle that goes nowhere. I would raise the calcium to 250 and let the ph go to 7.8 to 7.9.

 

[Marcion333]

today, 1/17/16, pH is 7.7 and TA 100 after soda ash, CH 250 after hardness up, FC 6.0, CYA 30 at room temp (using the larger Pentair CYA test kit instead of Taylor's k-2006 test). CSI is now -0.09. thanks for everyone's help.

also, Polyquat level is 6.5 ppm. the bane of a pool owner is algae growth. i like insurance.

 

[bdavis466]

Why did you add soda ash? That raises not only your pH but also your TA. There are 3 ways to raise the pH without effecting the TA (or very minor extent): Aeration, Time, or borax (although it does slightly effect the TA but not to the extent of other chemicals).

The TA takes a good amount of time to get it to the lower levels. It is never a good idea to raise the TA (unless it is very low) since that means that the pH will climb higher and faster.

Why polyquat? Algae can't grow with an adequate chlorine level. There is no need to waste the money.

 

[JoyfulNoise]

today, 1/17/16, pH is 7.7 and TA 100 after soda ash, CH 250 after hardness up, FC 6.0, CYA 30 at room temp (using the larger Pentair CYA test kit instead of Taylor's k-2006 test). CSI is now -0.09. thanks for everyone's help.

also, Polyquat level is 6.5 ppm. the bane of a pool owner is algae growth. i like insurance.

If you want "insurance" against algae if your FC drops below the minimum value (which it should not do), then you might be better served using 50ppm borates in your pool water. It has algaestatic properties and it helps reduce the rate of pH rise by acting as a secondary pH buffer. Borates also stay in your water long term and only require additions when there has been fresh water exchange.

Polyquat-60 is a fine algaecide, but it is broken down by chlorine over time into linear quats and it requires constant maintenance dosing. That makes it more expensive to use long term. Did you actually buy a QAC test kit (like a K-1582 from Taylor) or are you just calculating that value based on dosing?


Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[Marcion333]

i added soda ash to raise pH and the TA. TA before i used soda ash the TA was 60, and pH was actually 7.2, not 7.7. i forgot to correct this, sorry.
i determined polyquat level using taylor's QAC test kit.
i wasn't aware that borates were algaestatic.

 

[JoyfulNoise]

i added soda ash to raise pH AND TA. TA before soda ash was 60, and pH was actually 7.2, not 7.7. i forgot to correct this, sorry.
i determined polyquat level using taylor's QAC test kit.
i wasn't aware that borates were algaestatic.

See the following sticky and thread -

Borates - Why and How

Are Borates Safe to Use?

 

[bdavis466]

A TA of 60 is a good thing!!!! See post #7,9,13,25 and 28

 

[Patrick_B]

It's different for some. I have very high CH and TA fill water so 40-50 TA works well for me.

 

[neil.corrigan12]

Muriatic acid lowers the total alkalinity of pool. Make sure to dilute muriatic acid by adding the acid to the water. Am not sure, if Baking Soda can be added at same time as it will increase alkalinity.

 

[Marcion333]

can someone plz direct me to any scientific papers that discuss borates inhibiting algae growth?

 

[JoyfulNoise]

can someone plz direct me to any scientific papers that discuss borates inhibiting algae growth?

See HERE - http://www.inchem.org/documents/ehc/ehc/ehc204.htm#SubSectionNumber:9.1.1



Sent from my iPhone using Tapatalk,16k gal SWG pool (All Pentair), QuadDE100 Filter, Taylor K-2006

 

[Jezza]

Try this one - look for the one in Chem Geek's post.http://www.troublefreepool.com/threads/29518-Suggested-Borate-Levels

 

[Marcion333]

thanks for directing me to the article linked at chem geek's post. i found these two sections of the article very interesting/concerning:

Growth was strongly inhibited in 26% of the species at 50 mg boron/litre
(e.g. green alga Tetraselmis maculata; haptophyte Emiliania
huxleyi; diatom Phaeodactylum tricornutum) and in 63% of the
species at 100 mg boron/litre (e.g. chrysophyte Monochrysis
lutheri). The highest concentration was also lethal to 37% of the
species (e.g. diatom Cyclotella cryptica; dinoflagellate
Amphidinium carteri). Some species (e.g. green alga Monallantus
salina) required an adaptation period, with growth imperceptible
until 34-36 days after inoculation. Sequential transfer tests showed
that many of the initially inhibited species recovered after exposure
to 50 mg boron/litre, but not after exposure to 100 mg boron/litre.
The authors concluded that higher concentrations would be expected to
cause species redistribution, favouring growth of some forms and
suppressing growth of others.

Because calcium is known to inhibit the uptake of boron in plants and, therefore, to mitigate the
damaging effects (Reeve & Shive, 1944), the authors concluded that the
toxic effects of boron in macrophytes are more pronounced in soft
(low-calcium) water. (end)

CH of 250 is considered hard water.