Calcium hardness causing problems?

I have been reading all the great posts here and I know SOMEone will be able to help me!! My 3 1/2 year old pool is having 'issues' and I am worried it may have something to do with the calcium hardness. I have never tested it before this year because until now I only had the chlorine/pH test kit.

This Spring I have a really bad white 'ring around the pool' and the plaster looks stained pretty much throughout the pool - it looks splotchy and brownish. It does not sweep off. Is this what you refer to as 'scaling'?

Here are my test results:
CH - anywhere between 460-500 (tested my tap water too, it's only 20)
FC - 2
TC - 2
pH - 7.4 (just added acid because pH had gotten up to 8.2 - my pH always seems to creep up, so I have to regularly add acid)
TA - 110
CYA - 45 (just added some this week because it was almost non existent)

I have a salt water generator and unfortunately was not good about testing the pool this winter (I am in CA). I had black algae in a few spots last month (Chlorine generator stopped generating and I didn't realize it... it was low on salt, but that is taken care of now).

So I guess my questions are...
Is my calcium harndness too high? (I've seen conflicting information)
Where does the calcium come from??
Is there anything I can do about the ring around the pool and the 'stained' plaster?

Thanks so much for your help!
Nicole

Nicole,

Have you tested your fill water yet? In my area, I have pretty high CH in my fill water which makes my pool fairly high (~350 ppm). If your fill water has lower CH, you can partially drain the pool and refill to lower it. If your fill water has just as high CH, then about all you can do is work around it.

With the numbers where they are, your PH needs to be around 7.3 and no higher than 7.8 to prevent scaling. If you cannot lower your CH, I suggest lowering alkalinity down closer to 80. This will bring your balanced PH up to 7.4 but try to keep the PH below 7.8 and that should help a bit with your scaling. Also, SWGs tend to raise PH so when you lower the PH, try to get it down to 7.2 so you have some room for it to rise during the week. This will help keep your alkalinity from rising if it is too high in your fill water.

Nicole:
Is your pool vinyl or concrete/plaster/tiled?
What is the volume of it?
Have you tried ascorbic acid to clean the walls? I gather it's pretty good on stuff like that.

I am also in CA with SWG and Calcium is 520. I don't have scaling. I keep my ph in check with a good dose of muriatic acid once per week and my alk is at about 90. We got a lot of rain this winter so the salt got diluted. I was hoping the Calcium would too, but it is the same as last fall. I am thinking that a little bleach in the winter would do a lot of good...actually thinking of disconnecting the swg this coming winter since I let my water temp drop and the salt gets diluted in rainy season anyway.

Have you tried soaking your cell with muriatic acid solution?

Thanks for all the replies - here are the answers to your questions and more of my own questions:

I have an inground plaster pool, about 18,000 gallons

My fill water has a calcium level of only 20 so I have no idea where all this calcium came from!

I have not really tried anything yet for the stains, except for pumice stone (lots of elbow grease required!!) - do you mean for me to try ascorbic acid on the tiles or on the plaster stains?

I know I can partially drain and refill to lower the CH, but do I NEED to do that? (I'm a little worried about getting everything back in balance with new fill water.) Is the CH causing the problems or can I just leave it be and concentrate on the alkalinity? I will do the partial drain if it will help though...

And what about the dirty looking, stained plaster - is that something I need to deal with more aggressively? Is it something I have to treat specifically or will changing the water chemistry help? Is it a sign that something is terribly wrong?

I will try to lower the pH and TA down even more to see if that helps. My TA was back up to 130 this morning, but pH was still 7.4

Oh, and Salinda, yes, I regularly have to soak my cell with muriatic acid - the deposits on it get so bad!

Thank you!!!
Nicole

Keep working with the Muriatic Acid and aeration to lower pH and TA. The ring around the pool should gradually disappear.

The "brownish" stains could be a form of algae, and steady SWG operation might help to reduce it adding more bleach to save the cell life.

Hope this helps.

Pat

The scale on the tile will also come off very easily with a strong muriatic acid solution and a green pad. I use a squeeze water bottle to apply the acid, wait a few seconds for it to act on the scale, and then scrub it off with a green pad. Repeat as necessary. You need to wear good eye protection and latex gloves, be mindful of the wind direction and careful of the fumes. You also need to keep it off concrete, stone, and metals.

Always remember to add acid to water and not vice versa.

Thank you, Pat and Kurt for the replies. I just added some extra chlorine bleach, and some more acid to lower pH. I will try the acid to clean the tile ring.

Nicole

An update and plea for help once again!!

For about the past month I have kept my pH between 7.2-7.5 and lowered my TA to around 100 as suggested to help with the white 'ring around the tile' and stained, splotchy brownish plaster. I have also kept my Chlorine level at about 5 (cya is around 30). My Calcium has gone down slightly to 420 with a little draining and refilling. The water looks beautiful.

My white 'ring around the pool' is still there - I tried diluted muriatic acid and a 'green pad' to scrub it with, but all that did was make the white scaly stuff fizzle a bit. Didn't really remove any of it. The only thing that will help is a ton of elbow grease and pumice stones. Even then, there is still a residual white ring.

My plaster is still stained - splotchy brown all over, and rougher than it should be (poor kids toes get beat up). The only thing that will help this is a scrubbing with a pumice stone - I did this in one small area with good results - (silky smooth clean plaster) and dread having to do it to all three of my steps (they are especially bad).


Questions:

1. Should I just load up on pumice and scrub the tiles and plaster down? Is there anything else I can do? (called for a quote on tile cleaning - it's pretty expenive, but may end up being worth it!!)

2. Is a 'stained' looking plaster normal for a 3 1/2 year old pool??? (This part is really bothering me...)
Could this be due to inadequate sweeping of the plaster? My pool builder told me that I should sweep 'when needed' (which to me is just when it's visibly dirty).

3. Is it okay to keep my chlorine high all the time or should I let it go down now that it's been high for so long and I don't appear to have any issues with algae?

Thank you so much for any help or personal experiences you can offer, I appreciate it!

Nicole

Try the metals forum - there are a lot of stain experts there. I don't know if you have had a metals issue (from iron or copper) - but you can use absorbic acid (vitiman C tablets) and see if the brown stain goes away. If so then it is a metal stain.