Salt Cell Scaling After Less Than One Year

[DanF]

Hi Folks,

My Circupool RJ-45 has been installed for 11 months now and I really like it thus far...except for the significant scaling I'm starting to see on the cell.

I have been trying to keep my CSI negative, but with my CH approaching 700 it's becoming pretty difficult to do. I am not seeing any white flakes in the pool, but wondering what I should do next.

I'm definitely going to do a full drain this winter (probably December) which will take care of the CH issue. My pH has been fairly stable at around 7.4-7.6 but with TA at 80 I am struggling to keep CSI negative.

The "Cell Maint" light isn't flashing yet, and the system seems to be working fine. Should I try to drive the TA lower lower using muriatic acid and aeration cycles? Should I clean the cell now, and if so, should I avoid MA when cleaning and try to clean the cell with a garden hose?

 

[proavia]

Bring your TA down to 60.
If you stay on top of the pH, you can manage the water with CH at 1000 - but you need to check pH at least every other day. And you will go thru a bit more acid. My CH was almost 1300 this past Spring. I kept the TA at about 50-60 and pH in the low 7's to keep CSI slightly negative.

As for cleaning, maybe try getting the larger deposits out with a popsicle stick or similar wooden instrument. Then try hosing out with water. Only use a diluted MA solution if you still need to - and only soak for the minimum time necessary to get it cleaned out.

When is the last time you did a full drain? Chances are your CH will double (or more) every year given our hard water. Our fill water CH varies between 180 and 250 based on where the city is getting it from.

Any chance you have (or plan on getting) a water softener and can plumb a soft water line to your auto-fill?

 

[cowboycasey]

Circupool recommends not using MA at all.. only use a plastic or wooden stick for big chunks.. small stuff like you have there should be no problem

 

[DanF]

Thanks Gene!

Bring your TA down to 60

I'll give that a shot but historically that's been a tough number to hit with our fill water.

As for cleaning, maybe try getting the larger deposits out with a popsicle stick or similar wooden instrument. Then try hosing out with water. Only use a diluted MA solution if you still need to - and only soak for the minimum time necessary to get it cleaned out.

Good tip

When is the last time you did a full drain? Chances are your CH will double (or more) every year given our hard water. Our fill water CH varies between 180 and 250 based on where the city is getting it from.

I last drained in March of 2020. Yes, last time I tested my fill water it was CH 190, TA 130. I'm guessing we desert dwellers all had an above average rise in CH last summer because of record high temperatures and record low rainfall.

Any chance you have (or plan on getting) a water softener and can plumb a soft water line to your auto-fill?

I may look into it. However, a few years ago I replumbed my auto-fill so that it is fed from my irrigation system, rather than "house water". I did this to support the ability to turn off house water during extended vacations, while still being able to have grass/plants watered and have pool water level maintained. I don't have a softener currently, and don't know whether my soft water loop will provide soft water to the auto-fill (and irrigation) should I purchase one.

Circupool recommends not using MA at all.. only use a plastic or wooden stick for big chunks.. small stuff like you have there should be no problem

Thanks Casey. I will definitely try a non-MA approach first; hopefully that will be sufficient. Circupool's manual prescribes MA cleaning however, although this may be only for heavier cleaning, like when the "Cell Maint" light comes on:

To clean the Cell of mineral buildup: 1) Attach Cleaning Cap or Cleaning Stand (sold separately, available at www.circupool.com) and orient the Cell vertically. Place on the ground and stabilize so as to remain upright and prevent spilling. 2) In a separate bucket, mix one part muriatic acid into four parts water. Pour this weak acid solution directly into Cell. Ensure that the cleaning solution COMPLETELY fills the inside of the Cell.

 

[ajw22]

I have been trying to keep my CSI negative, but with my CH approaching 700 it's becoming pretty difficult to do.

Your problem is that the CSI is different in the cell then in the pool. All you can do is keep your pH, TA and CH down as best you can.

From TA - Further Reading

Why Should TA be Lowered with a SWG?​

Usually a TA on the high end is fine if the pH is stable. However TA does need to be adjusted down with an SWG. The problem is, INSIDE the cell, the CSI is very different than in bulk pool water.

With high TA and aeration from the bubbles the SWG creates, you'll get faster pH rise inside the cell and so there's more potential for scaling. With current reversal, the cell tends to stay clean but you'll get more snowflakes out of the returns. Calcium hardness is only one part of the equation.

If the SWG cell pH rises much above 10 (and it can easily do that) and if there is sufficient levels of carbonate ions available (CO3--), then you will get calcium carbonate precipitation. The higher the TA and pH, the more carbonate anions are available.

Borates are particularly helpful preventing scale in a SWG because the pKa for boric acid / borate anion buffering is approximately 9. That essentially means you get the maximum buffering capacity at a pH of 9 and that tends to hold down the pH rise inside the cell. Keeping the pH below 10 in the SWG cell reduces the risk of calcium and magnesium scaling (insoluble magnesium hydroxide precipitates at a pH of 10.2 or so).

 

[proavia]

I am in Chandler also. Maintaining a TA of 60 isn't all that difficult. But it does take a bit of time and effort. I refilled this Spring with a TA of 120. It took a while to get the TA down to 60.

Last Summer was brutal. More evaporation than usual, which cause more of a rise in CH.

Maybe look into a small RV water softener to hook to your auto-fill line only. Those type of small softeners need to be manually recharged from time to time.

 

[JoyfulNoise]

My softener is plumbed into my auto fill line and there are three 1/4 valves on the unit - I can shut off water to the softener (that kills all softened water to the house), I can shut off water to the house but leave the auto fill on or I can shut off water to the auto fill line but keep softened water flowing to the house.

Your irrigation line doesn’t used reclaimed water (purple water line) I hope? The “purple” water boxes are untreated, reclaimed, non-potable water … definitely not “pool worthy” …

You should seriously consider a whole house water softener. My signature line has a link to my softener install. I spent a lot of money on it but it has been worth every single penny. Since 2018 my pool water CH has not go up at all (I’ve done partial drains to get it below 600ppm and will do another one next month). In the 5 years prior to 2018 my pool CH went from 280ppm to over 1500ppm. The pool water chemistry unmanageable at that point.

I’ve always said it should be illegal to build homes in AZ without, at the very least, a fully plumbed softener loop in every garage. The municipal water here is terribly hard and results in damage to fixtures and water heaters costing homeowners a lot more money in repairs and replacements.

 

[Newdude]

Hey Dan !!! For the times that you do need to use MA, it will fizz like a kids science experiment. Trust me you’ll know when it stops. Rinse well immediately when it does.

 

[JoyfulNoise]

You can also use cleaning vinegar (6% acetic acid … available in Home Depot). It’s milder than MA and won’t damage the ruthenium surface. Highly concentrated mineral acids are not good for the transition metal catalysts.

 

[BowserB]

+1 on a whole house water softener. It's not just for the pool! History: We moved to Houston in 1971, and it was a huge shock. Grew up in Baton Rouge, LA a city with naturally soft water from artesian wells. Hard water almost made me want to move back (not really.) The downside of a water softener was sodium added to the water in exchange for removal of calcium and magnesium, so I passed on a water softener for many years. Then one day I learned about potassium chloride water softener salt. Wow. When I think of the dead water heaters I've contributed to landfills, the shower heads I've thrown in the trash, the perpetual hard water residue on faucets, dishes, dishwasher, etc., and other hard water drawbacks, I wish I had known.

However, we moved into a new house in 2017, so we could start better. I can remember draining water heaters every six months or so and watching all that white stuff pour out. I just flushed our two water heaters after four+ years and ... nothing. A little rust at first, but that was it. Shower heads work still like new. We squeegee the shower doors and walls most of the time, but if we don't, we come back later and there are no water marks. When I test CH in our faucet water (which is also the autofil water), the solution starts out blue, indicating -0- ppm. And best of all, with Morton Potassium Chloride water softener pellets, we're not adding sodium to the drinking water or the outdoor faucets (irrigation taps off ahead of the water softener.)

The only downside is the cost of potassium chloride water softener pellets. At Home Depot, Lowes, or Ace, a 40lb bag is $30-32, compared to $6-8 for the sodium chloride product. However at our favorite supermarket, HEB, the Morton product is $24 a bag. We go through 40 lbs about every 5 weeks or so. It is important that regeneration be based on volume of water, not time, so check before your buy. We also have a 5 stage filter with reverse osmosis in a special faucet in the kitchen for pure drinking and cooking water. According to the CDC, reverse osmosis is on a par with distillation for removal of contamination.

 

[DanF]

Your irrigation line doesn’t used reclaimed water (purple water line) I hope? The “purple” water boxes are untreated, reclaimed, non-potable water … definitely not “pool worthy

No; at least I don't believe so from this picture. I actually had the house shutoff valve moved up so that I could control both house water and irrigation water independently. But based on this picture I do not believe a water softener tied into my home's water softener loop will soften the irrigation water (which is also my fill water).

 

[DanF]

Thanks everyone for the expert advice I've come to expect here. What a great forum!

I took apart the cell today and rinsed out as much scaling as possible with the nozzle attached to my garden hose. I then tried some ice cream sticks and some plastic tools that weren't designed for cell cleaning without much luck; they were just too short. The way the cell is designed prevents access to the plates in some locations. Then I found the attached in my garage - it's actually a barbed plastic stick used to get hair, etc. out of drains - and looks a little like the one posted by @RJ-45 above. It worked pretty well! Was able to get most of the white stuff out without any chemicals. In the future I will try some cleaning vinegar as Matt suggested.

I'm seriously thinking about a water softener now and really should have purchased one years ago. I figure if I can't get soft water to my auto-fill because the auto-fil is plumbed from the irrigation loop, I can use a garden hose to fill the pool while I'm home, which is most of the year. Should cut way down on CH rise. And I'll also look into the RV water softeners that @proavia mentioned.

 

[proavia]

My soft water loop and softener are in the garage and supply only the house - so no outside hose bibs or irrigation. The original autofill was plumbed into the irrigation line. Recently, I drilled a hose in the garage wall and plumbed a soft water line to connect to the autofill.... copper until under ground and then sched 40 PVC for the underground portion. A little bit of digging and 60 feet of 3/4" PVC - soft water for the autofill. Just be sure to have a backflow preventer in the new soft water line run.