AquaBright Ecofinish--Alternative to Acid Washing

[JoyfulNoise]

I think in the Southwest, dumping the pool every few years is just a way of life. I know I am due for a drain as my calcium level is nearing 1200.

1100ppm here....sad to have to dump that much water but that's what everyone around here does - swim for 5 years or so, then dump the entire pool, acid wash the plaster and refill. I think a person could literally own a small business here just doing pool drains with plaster and tile cleaning.

And I so wanted to wait to drain until I could pull the trigger on AquaBright...


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[bdavis466]

1100ppm here....sad to have to dump that much water but that's what everyone around here does - swim for 5 years or so, then dump the entire pool, acid wash the plaster and refill. I think a person could literally own a small business here just doing pool drains with plaster and tile cleaning.

And I so wanted to wait to drain until I could pull the trigger on AquaBright...


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Just add more salt and borates and keep the pH around 7.4...you could let the CH get well above 2,000

 

[JoyfulNoise]

Just add more salt and borates and keep the pH around 7.4...you could let the CH get well above 2,000

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[pabeader]

Find some cheap water softeners on craigslist. Run pool water through them.

 

[xyz]

So what if it is potassium?

 

[JoyfulNoise]

So what if it is potassium?

Doesn't matter. Sodium or potassium is just fine.

Note - chloride levels will generally not increase from a water softener as the exchange is two sodium ions for one calcium ion. There may some residual brine left in the resin from regeneration but that will be gone quickly enough to not really matter.


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[xyz]

Doesn't matter. Sodium or potassium is just fine.

Note - chloride levels will generally not increase from a water softener as the exchange is two sodium ions for one calcium ion. There may some residual brine left in the resin from regeneration but that will be gone quickly enough to not really matter.


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Thanks!

So I assume I'm adding potassium chloride; will this hurt my SWG? will it help? Not matter?

Or would it be better for me to use Salt in my Water Softener?

 

[JoyfulNoise]

Thanks!

So I assume I'm adding potassium chloride; will this hurt my SWG? will it help? Not matter?

Or would it be better for me to use Salt in my Water Softener?

Just so we're clear - an exchange based water softener does not add any additional salt to the pool. The polymer resin simply holds and exchanges different cations (Na+ or Ca2+) and there's no change in chlorine (Cl-) levels. Brine solutions are simply there to regenerate the polymer resin by stripping away and flush down the drain the hard ions you don't want (Ca2+ and Mg2+) while replacing them with fresh sodium (or potassium) ions which do not contribute to scaling. Once the regeneration of the resin bed is complete, there is no "salt" in the system.

SO having said that, if one used KCl or NaCl in their softener, that is irrelevant to the SWG in terms of chlorine production. You can think of sodium and potassium as "spectator" ions, they simply are there for charge balance, nothing more.

 

[pabeader]

joyful - you said "Once the regeneration of the resin bed is complete, there is no "salt" in the system."

It amazes me how many people don't understand this.

 

[bdavis466]

I guess I'm one of them. All the softened water I've tested had very high salt levels.

There is also the big concern over drinking water from a softener because of the increased Sodium introduced into the diet even though the actual amount is very small in comparison to what is normally consumed.

 

[xyz]

I'm using Potassium Chloride, which may be less of an issue.

 

[JoyfulNoise]

I guess I'm one of them. All the softened water I've tested had very high salt levels.

There is also the big concern over drinking water from a softener because of the increased Sodium introduced into the diet even though the actual amount is very small in comparison to what is normally consumed.

In theory, the chloride levels should never change. The softener is filled with a cationic exchange resin, essentially a polymer that has sulfonate groups which are negatively charged and like to hold onto positively charged metal cations. The way it works is that the polymer is saturated with sodium ions to which the sulfonate group has an affinity to. When calcium laden water passes over or through the resin bed, the sodium ions are released and the calcium ions are captured because the sulfonate likes the calcium ions slightly better than sodium. Once the resin becomes loaded with calcium, you have to regenerate it. The way you do that is with a fully saturated brine (NaCl) solution (that's what all that salt is for) sitting inn a tank. You pass that completely saturated solution of salt through the resin bed and the overwhelming concentration of sodium causes the sulfonate groups to re-release the calcium and take on the sodium instead. Once the resin bed has soaked for a while in the brine solution, the brine gets rinsed down the drain and the resin bed is recharged with sodium. Now the process can begin anew.

The problem, like all engineering problems, is that theory and practice always have a slight mismatch. The resin will sometimes retain some of the salty water as will the plumbing. So, right after a regeneration cycle, the water coming out of the softener will often be slightly more salty than the input water. But it's usually not enough to make any difference in taste. And yes, people on low sodium diets should probably use potassium chloride instead of sodium chloride (at 2-3X the cost) OR use a whole-home RO system. However, resin based exchange softeners cost a few thousand dollars to install....a whole home RO system capable of producing 500-1000 gallons per day costs upwards of $10k to install plus monstrously high water bills and chemical additive expenses (RO systems typically need resin based water softeners on the front end to protect the RO filter from scale out OR the injection of large amounts of HEDP into the input stream). Potassium also has problems too - too much K can cause one's heart to stop....just ask anyone on death row....

 

[bdavis466]

Interesting... So no ill effects for the pool so long as the softener is large enough to keep up with the daily evaporation losses?

Why isn't everyone using one?

 

[rlefig]

pool and color look great getting ready for our aquabrite reno in a couple of weeks

 

[JoyfulNoise]

Interesting... So no ill effects for the pool so long as the softener is large enough to keep up with the daily evaporation losses?

Why isn't everyone using one?

I plan to ask when we install the home softener. They sell outdoor models and I have easy access to my autofill line. You can't fill a pool with it but top offs are fine. Chiefwej has one. He swears by it.

(That's for the catch Bob!!)


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[pabeader]

The key is that the timer/controller unit has to be properly adjusted to completely flush the resin bed after regen. Every unit I've ever had was in need of this adjustment, to one extent or other.

 

[Swampwoman]

When I was using a single tank softener and had old pool water, my salt level in the pool was about 2800...which made it really easy to switch to swg last spring

It could have been age of water and general accumulation, or exacerbated in part by maxing out the softener when topping up the pool, but since uograding to a dual tank system allowing for complete regeneration without interruption of water supply, AND having a new fill when the liner was changed, my salt level has stayed stable.

Since my pool only gets softened water, I will be able to report if there's any accumulation. So far there's not...we'll see about year two but I'm optimistic

And re

RO systems typically need resin based water softeners on the front end to protect the RO filter from scale out OR the injection of large amounts of HEDP into the input stream).

This is true...I have one that was plumbed to well water and the iron fouling and TDS were problematic...its rated for 50 gpd. I have a second system going in for the saltwater aquarium that's rated for 50 gallons per day but have been cautioned that in the real world its more like 30. Larger holding tanks alone are a couple grand but in this case its just going into a sump for water changes Whole house just wasn't practical...

 

[JoyfulNoise]

...Whole house just wasn't practical...

It rarely ever is. When you consider the chemical filtering or injection you need on the front end, then the storage tank(s), then the variable speed pump to re-pressurize your plumbing, then the post RO chemical adjustments (calcite block to add calcium back, UV disinfection), etc, etc, you're basically producing super expensive water of which 90% will be used to flush toilets or otherwise send down the drain.

Best to just get a large ion exchange softener with carbon and particulate pre-filters and then setup small, point-of-use RO filters as needed.


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[xyz]

OK, so time to report back, and a small correction. One of the things I reported as a slight negative of Aquabright is that my robot didn't scrub the waterline as aggressively. I've realized my robot has been running with a broken impeller for quite some time. I have a new one coming in, and I'm going to guess that this is why it seemed like it was anemic on the scrubbing. So that downside likely was not the aquabright at all.

Second, I assumed the high water stability was due to being winter and being cold. Well with the addition of solar in Feb, I have been keeping my pool at ~80. While this takes a lot more FC, it has not required me to add anything else. My Intelliph is set to 3%, so I'm automatically adding a tiny amount of MA. The 4 gallon tank I filled last fall is still more than half full. I've thought about turning off the IPH to see what would happen, but have not. I don' think it is necessary; I can only attribute this to the Aquabright.

I'm a little confused, because I thought there was no way around having to add MA when using a SWG. Maybe one of our chemists can set me straight on this.

Also, my CYA is a bit low so I'm adding some to hopefully reduce the FC use. I'm running at about 60% for 8 hours, so that seems like a lot of FC from an IC60. I also have been having a record amount of trash blowing or dropping into my pool, so maybe that is also causing excess demand. I think the extra rain this spring made more tree stuff to shed into the pool.

The ever so slight shedding of silica particles [or whatever it is in the AB] seems to have subsided to zero. There is no more evidence of shedding at all.

The only scrubbing I've done is around the steps where the robot can't get, and the spa. There remains some calcium deposits on the spa from before I switched to AB [I had massive calcium deposits in some places]; but I will be cleaning these up, and I don't expect them to return.

Calcium seems to be stable at ~ 220. It turns out my autofill is on my house water, so it is being softened, so I'm not seeing the CH growth I used to see. Supposedly the water softener adds salt, but so far, not enough to increase my salt level enough for my Taylor kit to measure it.

Anyway, it took a while to get here, but talk about an awesome pool! Always crystal TFP clear. If there were not so many leaves, it would be near zero maintenance!

So the Verdict remains AB is awesome.

 

[JoyfulNoise]

The chemistry of the SWG converting chloride into chlorine is pH neutral (See this post for details - Pool Water Chemistry). The primary reason why pH rises from an SWG is because of excessive TA and aeration - they hydrogen gas produced inside the cell aerates the water and helps to liberate CO2, this then drives the pH up. Since your water probably has very well controlled TA (due to the acid additions offsetting the TA added form fill water), your pH will remain quite stable as there is no cementious material (plaster) around to add alkalinity to the water.

Water softeners add sodium, not salt (sodium chloride). If they do add any salt then it is because of the residual salt water left in the exchange resin after it was freshly regenerated. Otherwise, the water that passes through the exchange resin loses one calcium ion (Ca2+) and picks up two sodium ions (Na+). There is, or should be, no increase in chloride ion (Cl-).