Do I need to worry about sulfates?

[EnoughToBeDangerous]

I've been using dry acid when I need to lower my pH, which is not often. I really don't want to keep muriatic acid around or use it if I can avoid it. I've used it for other purposes, and it's not really nice stuff. I don't want to have an accident with it and would prefer the safer alternative if possible.

Reading up on the forums it sounds like sulfates can build up in the pool. Is this something I need to worry about? The pool is a vinyl liner pool with no tile. The coping is a cement paver, ungrouted. But it doesn't really come in contact much with the water. Is there an antidote if the sulfates get to high?

 

[mknauss]

No SWCG?
As you drain your pool each year by a couple feet to winterize, the sulfate build up should be controlled. And if you are only using dry acid a couple times a season, that should not be an issue.
Draining the pool water is how to remove sulfates.

I am assuming this is a vinyl liner pool. Please complete your signature.

 

[Saturn94]

Sulfates can damage your SWCG cell.

 

[ajw22]

The antidote for sulfates is draining some percentage of your water and adding fresh water.

Your biggest issue is likely the effect the sulfates will have on your SWG.

Since you lower your pool water to winterize the pool you will remove some sulfates. But you can still get them accumulating if you don't drain much.

Problems sulfates can cause include:

• Sulfates can damage concrete & plaster
• Excess sulfates in water increases the likelihood of corrosion on metal parts
• Excess sulfates in splash out water leads to degradation of any concrete surfaces
• Sulfates degrade the coatings on SWG plates
• At high enough concentrations, sulfates can react with calcium to form spindly, needle-like crystals of calcium sulfate (gypsum)
• While sulfates in vinyl pools is typically not as problematic as in plaster pools, scaling of gypsum crystals can increase the risk of liner puncture.

Pentair specifically says on page 9 in the IntelliChlor SWG Manual - CAUTION: The use of dry acid (sodium bisulfate) to adjust pool pH is discouraged especially in arid regions where pool water is subject to excessive evaporation and is not commonly diluted with fresh water. Dry acid can cause a buildup of by-products that can damage your chlorinator cell.

 

[Mdragger88]

As far as the danger factor goes I feel like people take risks w/ dry acid that they would never take with liquid acid. (Since “it’s just PH down”)
It doesn’t mix as well & has the potential to float/sink & sit on surfaces doing damage- liquid on the other hand mixes quite quickly if poured slowly in front of a return.
Also the fact that powder can sit on your skin or blow in your face etc. without you realizing it until you feel the burn Whereas if the liquid gets on u you can feel it immediately & rinse it off.

 

[EnoughToBeDangerous]

Yes I do have a salt generator. Does that mean no dry acid at all for me?

 

[ajw22]

Yes I do have a salt generator. Does that mean no dry acid at all for me?

What model SWG?

Creating your signature would be helpful in giving you advice.

 

[EnoughToBeDangerous]

As far as the danger factor goes I feel like people take risks w/ dry acid that they would never take with liquid acid. (Since “it’s just PH down”)
It doesn’t mix as well & has the potential to float/sink & sit on surfaces doing damage- liquid on the other hand mixes quite quickly if poured slowly in front of a return.
Also the fact that powder can sit on your skin or blow in your face etc. without you realizing it until you feel the burn Whereas if the liquid gets on u you can feel it immediately & rinse it off.

I have not had this problem, it usually dissolves very fast, and it doesn't splash or cause fumes. If you spill it on the pool deck it can be swept or hosed into the pool relatively safely, but I would not be excited about cleaning up an hcl spill breaking bad style. And if it touches skin while dry, you probably get away clean, whereas the HCL will immediately do damage.

 

[EnoughToBeDangerous]

What model SWG?

Creating your signature would be helpful in giving you advice.

It's an autopilot digital.

 

[ajw22]

And if it touches skin while dry, you probably get away clean, whereas the HCL will immediately do damage.

HCL will not do immediate damage to your skin. If you get HCL on your skin just dunk your hand or arm into the pool. BTDT.

 

[EnoughToBeDangerous]

What model SWG?

Creating your signature would be helpful in giving you advice.

Ok I created a signature! Thanks.

 

[ajw22]

It's an autopilot digital.

Well Autopilot recommends dry acid as one of the ways of reducing pH in their SWG manuals.

 

[EnoughToBeDangerous]

So that would suggest that they don't prohibit it, but would you expect it will damage my cell?

 

[mknauss]

So that would suggest that they don't prohibit it, but would you expect it will damage my cell?

Possibly. Other issue is the creation of calcium sulfate scale on the plates. The high pH in the SWCG can create scale. Calcium sulfate scale is gypsum.

 

[Saturn94]

Well Autopilot recommends dry acid as one of the ways of reducing pH in their SWG manuals.

Interesting. It seems the technology inside the cells would be pretty much the same among the different SWCG manufacturers, so it‘s puzzling AutoPilot recommendations either muriatic or dry acid.

 

[mknauss]

Interesting. It seems the technology inside the cells would be pretty much the same among the different SWCG manufacturers, so it‘s puzzling AutoPilot recommendations either muriatic or dry acid.

They assume large water replacement. Correct in Florida, the north, etc. But in the southwest and west, not so much.

 

[EnoughToBeDangerous]

Thanks. Is it possible to measure the sulfates to determine if they are building up?

 

[mknauss]

Thanks. Is it possible to measure the sulfates to determine if they are building up?

Not with residential pool owner methods.

 

[EnoughToBeDangerous]

Not with residential pool owner methods.

I understand. Tough choice. Do I want to risk getting sulfates in my salt cell, or risk getting hydrochloric acid on my hands.

 

[Rich807]

Since you seem to be very worried about it, you could easily just wear some inexpensive & widley available PPE to protect against spilling MA on yourself. A pair of rubber gloves, safety glasses or shield, Done.