Cleaning the cell

[Nikilyn]

I’ve watched videos about how to clean it but I have a question about the acid. If we have 14% MA, do we need to dilute it or is it fine as is? Or do we really need the 31%?

 

[mknauss]

First, do you need to clean the SWCG cell? If your CSI is kept in the -0.3 to 0.0 range, it should never need cleaning.

If you do find that you must use acid to remove the scale buildup, it should be cut at least by 5:1 water to acid. That is with the 14%.

 

[JoyfulNoise]

Can’t stress this enough - NEVER pour concentrated acid into an SWG cell!! That is the surest way to destroy it quickly.

I know there are lots of YouTube videos out there of service guys dumping acid straight into SWG cells and that is totally wrong. They simply don’t understand how they work and how delicate the catalyst coating is. Always ask for advice here before you do anything that is taught on Facebook or YouTube. 99 times out of 100 they are all wrong.

 

[Nikilyn]

Yes, it needs it. Our CSI is -0.37. It used to be 0. I’m not sure what that means or how you fix it. I just started the process of lowering TA today. The other numbers look good.
You still cut the acid 5:1 with 14%? Every video I watched said 4:1 with 31%. We did 4:1 with the 14%. What ratio do you cut the 31%?

 

[mknauss]

What ratio do you cut the 31%?

10:1

You need to control the pH and TA along with the CH to keep your CSI in check. Each time you clean the SWCG, you remove some of its life.

I have never had to clean my cell with acid. 7 years of operation. With the same fill water you have.

 

[Nikilyn]

I just know that I could see some scale on it. I retested my pH after I lowered it for the TA and it now says my CSI is -0.60. My other numbers are good except TA is 100. Will CSI get better once I get the TA down?

 

[bertschb]

You still cut the acid 5:1 with 14%? Every video I watched said 4:1 with 31%. We did 4:1 with the 14%. What ratio do you cut the 31%?

I just cleaned my cell for the first time (pool is 7-8 months old). I diluted my 31% acid about 5-1 and when I added that to my cell, it foamed like CRAZY and overflowed the cell even though I poured it in slowly and didn't overfill it. It freaked me out as I was already a little nervous about cleaning it. I'm diluting to more like 8 or 10-1 next time and then filling only half full until I know it won't look like a school volcano experiment.

 

[mknauss]

When your pH gets to 7.8, lower it to 7.4. The TA will fall and stabilize. Your CH is fine right now, but will go up with evaporation. I assume you are NOT using softened water for fill water. If you can, you should.

 

[mknauss]

Again, if you can push the scale out with a popsicle stick or use a stream of water to blow it out, do that before using acid. If you clean the cell with acid often, it will not last very long.

 

[Newdude]

And stop as soon as the fizzing stops. (You'll know when ) Rinse thoroughly immediately.

 

[Nikilyn]

When your pH gets to 7.8, lower it to 7.4. The TA will fall and stabilize. Your CH is fine right now, but will go up with evaporation. I assume you are NOT using softened water for fill water. If you can, you should.

I would love to add softened water but it’s the cost. Not really sure how they would connect the pool to our softener without a whole lot of difficulty.

 

[bertschb]

I would love to add softened water but it’s the cost.

I'm using my RV water softener. It's not connected to my autofill but I have no problem adding water manually as needed. If we're away from home for extended periods of time, I'll switch to the autofill system.

 

[Oly]

If your CSI is kept in the -0.3 to 0.0 range, it should never need cleaning.

This was not my experience during my first season with the SWCG.
As water temps increased mid summer I observed rapid cell scaling even with CSI well below -0.3. I was getting reduced cell output after only 3 weeks from a cleaning.
What did slow the scaling was lowering the TA to 50-60 ppm and keeping the pH at or below 7.4. My fill water is high in TA (150+) and during high evaporation I have to anticipate the rise with frequent topping off.
Although scaling did continue it was significantly slower and softer to the point it would self clean a bit during the polarity shift, especially when the pump was at a higher rpm.
Cleaning the cell also is easier as the soft scale is easily dislodged with a long zip tie and a water jet rinse. I have not had to resort to the acid bath yet but I must stay ahead of the chemistry at peak summer.
I will say that the CP RJ-60+ cell is not easily cleaned manually due to the many plates and the position of the cell within the plastic housing. Access is limited and the long zip tie is my favorite tool.

 

[Charlie Bezzina]

Zip tie! Brilliant idea! have been using a bamboo skewer and it is too tight between the outer plates of the Hayward cell.