How long can you go w/out balancing PH?

[MostlyCanuck]

Hiya:

In the process of building IG vinyl pool, while soaking up as much good sense from here as I can to prepare myself.

It just occurred to me, every time we go to the cottage in summer - long weekends and the odd week here and there - no-one will be home balancing the chemistry as I'm not planning to pay PB for weekly maintenance. Chlorine will be taken care of by SWG. However, PH won't. And I guess with SWG running constantly in the background, PH will drift materially.

(I will consider adding an Intelliph in the future, but only if 100% necessary - and would rather not).

So my question is, how long can you sustain out-of-range PH before problems arise? I'm guessing immediate term is subotimal (mild eye/skin irritation, etc) and then there's some trigger point beyond which bad things escalate (equipment corroded, vinyl liner damaged, etc).. what I don't know is whether these are problems that emerge after prolonged unbalance (weeks and months), or if there's any real damage done quickly after a week or two of inbalance.

Grateful for any thoughts

 

[mknauss]

PH will drift materially

Not necessarily. pH rise is due to adding high TA fill water due to evaporation and aeration. Many SWCG owners that do not have those issues see little or no pH rise.

Only real issue with high pH is scaling. First in the SWCG cell itself, then on the pool surfaces.

 

[Katodude]

Dont stress it. You have a vinyl pool so your pH wont drift as much as a plaster pool. Also once you get it balanced you probably wont have to adjust pH more than a couple of times a month.

 

[MostlyCanuck]

appreciate both answers above - very reassuring indeed! i'd love to spend a week at the cottage without stressing about PH back home lol!

to my question though, if it does drift out of balance, and one is away on vacation of a week or maybe two - is that likely to already generate damage, or do you need prolonged weeks/months of PH outside parameters before issues set it?

 

[mknauss]

to my question though, if it does drift out of balance, and one is away on vacation of a week or maybe two - is that likely to already generate damage, or do you need prolonged weeks/months of PH outside parameters before issues set it?

Only real issue with high pH is scaling. First in the SWCG cell itself, then on the pool surfaces.

 

[MostlyCanuck]

lol i love that you answered my question by repeating your answer from before... funny. i guess i dont fully understand it though - it's not like i didnt read it before!

isnt out-of-balance ph also an issue for corrosion of equipment, damage (stain/brittle/wrinkly) liners, etc? if scaling really is the only issue with unbalanced ph, that sounds like something that can be cleaned and addressed easily... but i was of the impression that the wrong ph could do far more damage than that...?

 

[mknauss]

On the high end of pH, not really. It is not good but to be honest, unless you add caustic chemical product to the water, the pH will not go above 8.4 or so. That is the natural level for most fresh water systems.

Low pH can be very damaging. Even a short while under 7 can destroy a heater core, mess up your liner, etc.

 

[MostlyCanuck]

On the high end of pH, not really. It is not good but to be honest, unless you add caustic chemical product to the water, the pH will not go above 8.4 or so. That is the natural level for most fresh water systems.

Low pH can be very damaging. Even a short while under 7 can destroy a heater core, mess up your liner, etc.

that's really helpful, thx.

apologies for the ultra-basic question here - i'm sure it's been posted somewhere in the past but i find i get so easily confused without a decent chemistry background: in what circumstances do you fall into low ph then? i thought i understood that some of the components of my pool (SWG running 24/7, waterfall) would cause ph to drift upwards via aeration as the natural trend. if the downside of that higher ph is only scaling, i'm less worried about a short-term unbalance, for sure. but then, what should i be concerned about? what's going to push my ph low, rather than high, to corrode the heater and damage the liner? if the pool naturally drifts up, that sounds like corrosion from low ph isnt a concern either... what am i missing? gee, i wish i had paid more attention to chemistry classes back in high school

 

[mknauss]

Acid or chemicals that are acidic will lower your pH. Trichlor and dichlor are the most prevalent pool store chemicals that are very acidic and lower the pH.

 

[ajw22]

i thought i understood that some of the components of my pool (SWG running 24/7, waterfall) would cause ph to drift upwards via aeration as the natural trend.

There are many natural factor that cause water with pH in the mid 7's to move higher until the pH reaches an equilibrium, usually in the mid 8's. Your TA determines what your pH equilibrium value is. Areation caused by water features, SWG bubbles, wind, splashing all casue the TA to raise the pH.

if the downside of that higher ph is only scaling, i'm less worried about a short-term unbalance, for sure. but then, what should i be concerned about?

Scaling is one problem that happens at higher pH. Another can be metals staining if you have metals in your water. Higher pH can cause chemicals to precipitate out of the water.

what's going to push my ph low, rather than high, to corrode the heater and damage the liner?

Chemicals that have acid in them. Particularly solid chlorine products that contain acid and are constantly used.

if the pool naturally drifts up, that sounds like corrosion from low ph isnt a concern either

Not unless you have a constant feed of trichlor or dichlor that contains acid pushing your pH down. And water with a very low TA.

 

[MostlyCanuck]

Acid or chemicals that are acidic will lower your pH. Trichlor and dichlor are the most prevalent pool store chemicals that are very acidic and lower the pH.

so, if i use a SWG for chlorine (as opposed to pucks or granules that come combined with acidic chemicals), my ph will always only drift up instead of down? and hence might need to clean up scaling but never worry about corrosion?

if this is indeed the case, i'm a really happy camper. somehow i thought i read endless stories of saltwater pools linked to corrosion, where the corrosion was due to the ph inbalance rather than the salt itself (meaning the ph in the saltwater pool would somehow drift so low to cause corrosion)...

if i am following what you are suggesting, a pool with tri/dichlor pucks will naturally see ph drifting low (and hence experience more corrosion problems), while a pool with a SWG will naturally see ph drift up (hence experiencing scaling, but no corrosion problems)... but then what's the concern about saltwater and corrosion that i seem to read everywhere? from cupronickel heat exchanger upgrades, to thicker marine grade stainless steel....generally saltwater pools seem more problematic with corrosion (due to ph drifting).... what you suggest sounds like the other way around.

what am i missing / misunderstanding?

 

[MostlyCanuck]

Not unless you have a constant feed of trichlor or dichlor that contains acid pushing your pH down. And water with a very low TA.

you and marty got back to this same point. ok, then. i was typing my followup to him as you wrote this... so it really does sound like corrosion (given it's a low-ph issue) is more of a concern for tri/dichlor users than salt users... i would swear i thought i spent to the past few weeks reading the opposite (saltwater=more corrosion), but i guess i mis-understood.

 

[ajw22]

i would swear i thought i spent to the past few weeks reading the opposite (saltwater=more corrosion), but i guess i mis-understood.

There are concerns about saltwater causing corrosion, not because of low pH, but because of the rusting process that salt causes. People who live near the ocean see the effects of corrosion from seawater. However seawater has 10X the salt that a salt water pool has - 30,000 ppm vs. 3,000 ppm.

In addition there is little to corrode in normal pool equipment unless you have some metal things attached to your pool. Pumps, filters, heaters, valves are all made of non-corrosive materials. Except for the copper heat exchanger in gas heaters.

Some folks do not handle their acid additions properly when trying to lower their pH and lower it too much into the danger zone. So some low pH corrosion events are self induced maintenance errors.

 

[MostlyCanuck]

There are concerns about saltwater causing corrosion, not because of low pH, but because of the rusting process that salt causes. People who live near the ocean see the effects of corrosion from seawater. However seawater has 10X the salt that a salt water pool has - 30,000 ppm vs. 3,000 ppm.

In addition there is little to corrode in normal pool equipment unless you have some metal things attached to your pool. Pumps, filters, heaters, valves are all made of non-corrosive materials. Except for the copper heat exchanger in gas heaters.

Some folks do not handle their acid additions properly when trying to lower their pH and lower it too much into the danger zone. So some low pH corrosion events are self induced maintenance errors.

ah - sounds even more reassuring.

let me test this, then. my PB first suggested this acrylic sheer descent for our water feature (Acrylic Sheer Descents - Weirs). then when i said i was looking for a SWG, suggested a pricey (~2k) upgrade to go from acrylic to "marine-grade stainless steel"...suggesting it would better withstand saltwater corrosion.

isn't acrylic another word for plastic, which doesnt corrode at all? would you see a reason to upgrade to "marine stainless steel" to protect against corrosion (or any other reason)?? i dont mind spending extra on something smart, but i do mind spending on useless Crud...

 

[Teald024]

but then what's the concern about saltwater and corrosion that i seem to read everywhere?

Much is fear of salt water and the myth that persists of saltwater ruining pools. At really high concentratins, salt does damage metal parts (ocean, salt on roads) but at pool salt levels, the corrosion issue is really overstated. Most pool components are fairly salt resistant. For your IG vinyl pool, you should have little to worry about when you use saltwater. Many issues that are attributed to salt are really pH issues or stone that is susceptible to damage either way,

 

[Teald024]

isn't acrylic another word for plastic

Well... considering they make acrylic salt water aquarium tanks, I'd say your builder really isn't informed. This isn't surprising as many builders are propagating the myths of salt water pools.

 

[MostlyCanuck]

Well... considering they make acrylic salt water aquarium tanks, I'd say your builder really isn't informed. This isn't surprising as many builders are propagating the myths of salt water pools.

they've been building pools where i live for 80 yrs with solid reputation, so sure are informed... but they might be trying to upsell me based on misconceptions. that wouldnt surprise me..

any thoughts on the acrylic sheer descent vs marine-grade sheer descent offer? the thing will be housed inside a wall with virtually no hanging parts other than maybe the smallest edge... so i cant seen the acrylic one breaking vs the marine-SS. and isnt acrylic plastic, meaning it would never corrode vs marine-grade SS which may well be "marine-grade" but still a metal that can corrode?

 

[ajw22]

isn't acrylic another word for plastic, which doesnt corrode at all?

Yup.

would you see a reason to upgrade to "marine stainless steel" to protect against corrosion (or any other reason)??

Nope.

i dont mind spending extra on something smart, but i do mind spending on useless Crud...

Agreed.

The acrylic version is preferable for all pool environments.

 

[Teald024]

acrylic is a type of plastic. I see no reason to change to acrylic just because you mentioned a SWG. I'd go with acrylic myself. Unless he is trying to up sell you or maybe thinks you want "better" quality. If he was willing to use an acrylic descent and you are happy with the offer, then go with it.

 

[MostlyCanuck]

Yup.



Nope.


Agreed.

The acrylic version is preferable for all pool environments.

that's what i thought!