Lowering pH saltwater pool

[P2Pool]

Hello all! Still a novice to pool chem, but recently purchased a Taylor K-2006 SALT kit and came up with the following

TAlk: 120ppm
FC: 2ppm
CC: 0ppm
CH: 180ppm
pH: ~8
Salt: 3368

I have a saltwater pool (nature 2 fusion) and a fiberglass pool of ~15400 gal (Latham Corinthian 16) and would like to lower pH (understand that saltwater pools run more alkaline given the NaOH when converted). Two questions, I do not add cyanuric acid as I’ll have a auto pool cover to help retain the chlorine though is it necessary to add? Also, to lower pH, the acid demand test was 2 drops to get pH to 7.4, to which I intend to add 27.48 floz of 31.45% muriatic acid. Is there a particular acid that’s better for fiberglass pools or does it not matter? Also, do I add it directly into the pool or mix in bucket then add? I read that it’s necessary to add 50% then 25, 15 & 10 slowly to avoid rapid pH decrease and recently learned that I need to turn off the salt generator prior to adding which I will do. Any other tips prior to me adding would greatly appreciate the help. Thank you all kindly in advance and seriously this forum is amazing!

 

[jedigrover]

I suspect you will need some level of CYA both to retain chlorine when the pool is not covered, as well as to make it more comfortable to swim in. Some others can chime in here with more knowledge than me, but you might consider treating it similarly to an indoor pool.

There aren't any different "types" of muriatic acid. Just stay away from the "acid magic" stuff. It's is only marginally safer than plain muriatic acid at 3x the price. Just handle Muriatic Acid in a safe manner. You add acid directly into the pool, in front of a return. Brush the area below immediately afterward (just a little, to make sure it mixes well and doesn't sit on the bottom as it is denser than water until it mixes). It is not necessary to meter it out like that. It is not necessary to turn off the SWG for adding relatively small amounts of acid (28oz is a small amount, trust me) at a return. (It IS necessary to turn off the SWG before adding salt, as high salt can produce high amps in the SWG)

The best technique is to "float" the jug on the pool surface (that will take some of the weight off so it is easier to handle) and slowly pour the desired amount into the water right at a return.

When handling acid of any kind, just remember the rule: "Do what you oughta, pour acid into water." Never pour water into acid. High concentration (acid) always goes into low concentration (water).

 

[P2Pool]

Thank you Master Grover Will use those techniques to pour and avoid turning off the generator. Have quite a bit to learn as an apprentice and truly appreciate the help

 

[Mdragger88]

@P2Pool
At least some cya is preferable - 30ppm or so like a manually chlorinated pool is a start-
higher cya levels (60-80ppm) are recommended for swg’s to protect the chlorine from the sun as it is produced slowly over time - your cover may negate some of that need.
Having cya does a couple things besides just protecting chlorine from the sun
* it buffers the harshness of adequate fc levels for swimmers, equipment (like that expensive cover), & surfaces as mentioned above
* it also allows u to maintain a higher fc level than u are now which prevents u from going below minimum or worse, to zero, when the bather load is higher or there’s debris.
Follow the FC/CYA Levels at all times.
Even with no cya the fc should never fall below 2ppm lest nasties will grow. Person to person transmission of pathogens is no joke.
Clear water doesn’t automatically = safe water.
Pool Care Basics

 

[P2Pool]

@P2Pool
At least some cya is preferable - 30ppm or so like a manually chlorinated pool is a start-
higher cya levels (60-80ppm) are recommended for swg’s to protect the chlorine from the sun as it is produced slowly over time - your cover may negate some of that need.
Having cya does a couple things besides just protecting chlorine from the sun
* it buffers the harshness of adequate fc levels for swimmers, equipment (like that expensive cover), & surfaces as mentioned above
* it also allows u to maintain a higher fc level than u are now which prevents u from going below minimum or worse, to zero, when the bather load is higher or there’s debris.
Follow the FC/CYA Levels at all times.
Even with no cya the fc should never fall below 2ppm lest nasties will grow. Person to person transmission of pathogens is no joke.
Clear water doesn’t automatically = safe water.
Pool Care Basics

Thank you for this! I’ll look to add some then moving forward and will go low and slow to 30 ppm. Appreciate the insight

 

[pjt]

nature 2 fusion

Remember to remove the mineral portion. You don't want to add any metals/minerals to your water.

the acid demand test

Use PoolMath. Much easier.

27.48 floz

That level of precision is unrealistic and unneccesary. You'll be pouring straight from the jug into your pool. I visualize filling soda cans as I'm pouring (~12 fluid ounces) to get an estimate. Also, a quart is 32 fl oz, so if I pour in a quarter of the jug, it's around that amount.

I read that it’s necessary to add 50% then 25, 15 & 10 slowly to avoid rapid pH decrease

You didn't read that here. Totally unneccessary.

I need to turn off the salt generator prior to adding

Also incorrect. The only time you'll turn off the SWG is adding salt until it's evenly mixed in.

 

[P2Pool]

Remember to remove the mineral portion. You don't want to add any metals/minerals to your water.


Use PoolMath. Much easier.


That level of precision is unrealistic and unneccesary. You'll be pouring straight from the jug into your pool. I visualize filling soda cans as I'm pouring (~12 fluid ounces) to get an estimate. Also, a quart is 32 fl oz, so if I pour in a quarter of the jug, it's around that amount.


You didn't read that here. Totally unneccessary.


Also incorrect. The only time you'll turn off the SWG is adding salt until it's evenly mixed in.

Thanks for the reply. I just added up from the Taylor manual so completely understand can’t be that precise haha! Do I add the acid directly in front of the skimmer? Thanks again

 

[Rancho Cost-a-Lotta]

Thanks for the reply. I just added up from the Taylor manual so completely understand can’t be that precise haha! Do I add the acid directly in front of the skimmer? Thanks again

Don't add acid into or in front of the skimmer...

With the pump running, pour a pencil-size stream in the current of one the returns (jets). It will dilute quickly that way to avoid damage to the surface.

 

[P2Pool]

Don't add acid into or in front of the skimmer...

With the pump running, pour a pencil-size stream in the current of one the returns (jets). It will dilute quickly that way to avoid damage to the surface.

Got it. Thanks