Salt cell constantly clogged

[ddas]

My salt cell seems to become constantly clogged with (what I assume is) calcium. Is this normal? I end up having to acid-wash it every few months or so. This is what it looks like:

http://imgur.com/VqEQPEA
http://imgur.com/qmosTli

My stats:
FC: 11 (I'm at the tail end of containing a small algae outbreak)
pH: 7.7
Salt: 3800
CYA: 90
Alkalinity: 100
Phosphates: 500
CH: 700

 

[jblizzle]

With your high CH level, not unexpected especially if you keep the pH too high. Try keeping the pH under 7.5 and see if it helps.

 

[UN1017]

That is some pretty intense scaling. Like Jason said, you have or keep your pH down, which will mean frequent acid additions. It's kind of ironic that the same thing that drives up your pH also needs a lower pH to avoid clogging.

On a side note, what kind of test kit are you using? I didn't see it referenced in any of your previous posts.

 

[Juan]

Some thoughts . . .

First of all, if you only clean the salt cell "every few months or so," you are doing very well. I would clean the cell more frequently to head off clogging to that extent. As mentioned above, keep your pH in the proper range.

To clean the cell, use four parts water to one part acid (4:1). I mix the diluted acid in a gallon jug.

Make yourself (or buy) a cleaning stand. You can use a plug to close off one end of the cell, or you can make a screw-on stand or plug. I have an Aqua-Rite T-15 cell. Since the threads on different PVC unions are not standard and vary from manufacturer to manufacturer, you need to find a union whose threads will match those of the cell. For my Aqua-Rite cell, the threads of a 1-1/2" union manufactured by American Valve (sold at Lowe's) will screw onto the end of the cell. Buy a union and cap it off, and -- voila! -- you've got a cleaning stand or an end cap.

Pour the acid mixture into the cell and let it bubble away. If you make two end caps for the cell, you can shake the mixture inside and agitate it to help loosen hard deposits. It can take a fair amount of time to remove all the deposits.

When you're finished, don't pour the mixture back into the pool! Why pour all that calcium right back into your pool water? Discard it in some other responsible way.

Don't use calcium hypochlorite to shock your pool You're adding calcium to the water, and it will collect on your salt cell plates.

Here in Arizona, we have hard water, so all the water coming into the pool to replace what's lost through evaporation is just adding calcium to the water. We have to change our pool water here every 4-5 years or so, just because the total dissolved solids keep increasing as water is added.

Salt cells are not as mysterious as people might believe. Passing an electric current between many conductors in a saltwater solution will result in electrolysis and the production of free chlorine. The problem is that the anode (positive conductor) will corrode and disintegrate.

In a salt cell, the conductors are made of ruthenium-titanium because they will not corrode during electrolysis, like other conductors do.

NEVER insert anything into a salt cell to try to clean or scrape off calcium deposits. I don't even recommend using a pipe cleaner. You will do more damage to a salt cell by scratching the plates with some foreign object than you will by strengthening the acid mixture or letting the acid work longer. Scratching the plates will significantly shorten the life of the cell.

Best wishes!
Juan

 

[bobodaclown]

If you use poolmath http://www.troublefreepool.com/calc.html you'll notice a time item called CSI. You'll want to stay in negative values (guide values are posted). Clogging will tend to slow.

 

[Chuckiechan]

Great post. My only concern is capping off the cell and having acid squirt out due to pressure when you unscrew the caps.

And thanks for the Lowe's tip. I was about to by some couplers for way too much money!

 

[bobodaclown]

only cap one end, stand on end.
This video is a little dry, but gives you the procedure: http://www.youtube.com/watch?v=4Kn5MD7lDyQ

 

[mcdickey]

Is the 4:1 water to acid ratio for cleaning the cell based on an acid strength of 31.45%?

 

[bobodaclown]

Yeap that will work nicely 4:1 with 31% stuff.

 

[Juan]

Here's an idea for a useful little project:

1. Buy two 1-1/2" unions that are compatible with the threads on your salt cell.
2. Buy a stick of 1-1/2" PVC (you'll use less than 2 feet of it)
3. Buy two 1-1/2" PVC caps.

There have been several times when I've wished that I've had an insert to take the place of my salt cell while my salt cell is removed for cleaning or service.

Cut the 1-1/2" PVC to the proper length so that it fits together with the male side of the unions to make an insert that is exactly the same length as your salt cell. Glue it all together. My T-15 cell is about 12-3/8" long.

Now when you have the salt cell removed from the system, you can thread the pipe insert in its place. You can still run the pump and filter, vacuum, etc., while you're servicing the salt cell. The salt cell can sit off to the side and fizz happily away while you're backwashing, vacuuming, or doing whatever you need to do.

Some of you might have the salt cell isolated by valves, so you can just close the valves and keep the system operational. I don't have that setup, so when my salt cell is removed, I can't run the system. I could reconfigure the plumbing and incorporate some valves, but this simple solution to make a replacement insert is cheaper and easier.

Finally, cut two pieces of the 1-1/2" PVC pipe to a length of about 3" each. Glue an end cap onto each one, and glue the other end into the female side of the unions. Now you have end caps that you can screw onto the ends of your salt cell, so that you can pour acid into it for cleaning.

When you're done servicing the cell, screw the end caps onto the ends of your pipe insert and store the whole apparatus together. Very convenient!

Have fun!
Juan

 

[JamesW]

I recommend getting the TA down to about 60.

 

[Xexys]

Here's an idea for a useful little project:

1. Buy two 1-1/2" unions that are compatible with the threads on your salt cell.
2. Buy a stick of 1-1/2" PVC (you'll use less than 2 feet of it)
3. Buy two 1-1/2" PVC caps.

There have been several times when I've wished that I've had an insert to take the place of my salt cell while my salt cell is removed for cleaning or service.

Cut the 1-1/2" PVC to the proper length so that it fits together with the male side of the unions to make an insert that is exactly the same length as your salt cell. Glue it all together. My T-15 cell is about 12-3/8" long.

Now when you have the salt cell removed from the system, you can thread the pipe insert in its place. You can still run the pump and filter, vacuum, etc., while you're servicing the salt cell. The salt cell can sit off to the side and fizz happily away while you're backwashing, vacuuming, or doing whatever you need to do.

Some of you might have the salt cell isolated by valves, so you can just close the valves and keep the system operational. I don't have that setup, so when my salt cell is removed, I can't run the system. I could reconfigure the plumbing and incorporate some valves, but this simple solution to make a replacement insert is cheaper and easier.

Finally, cut two pieces of the 1-1/2" PVC pipe to a length of about 3" each. Glue an end cap onto each one, and glue the other end into the female side of the unions. Now you have end caps that you can screw onto the ends of your salt cell, so that you can pour acid into it for cleaning.

When you're done servicing the cell, screw the end caps onto the ends of your pipe insert and store the whole apparatus together. Very convenient!

Have fun!
Juan

Is this really necessary? I've read many places that you should only be cleaning the cell with the MA mix for only 20 minutes or so. Do you really need to run your pump while you clean your cell for this time?

 

[JamesW]

A bypass for the cell can come in handy in rare occasions. However, I don't think that it's worthwhile for most people. It's not too hard to make if you can find the unions.

Also note that you should never cap both ends of the cell at the same time while acid cleaning because carbon dioxide gas is released, which can cause pressure if contained. There could be a high pressure release of acid when uncapped or possibly even an exploded cell.