Hardness level?

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texascajuns

texascajuns

0
May 28, 2008
14
Houston, TX
Hello All,
Hope someone can help me figure out my hardness problem and how to correct it since the 15
year old at the pool store could not help. I currently test chlorine, pH, and TA at home but follow up with pool store test every couple of weeks to check other chemicals. I had to drain about 20% of the pool a couple of weeks ago because I had too high salt contect and my SWG was not working, so that was done. Now, here are my readings this week:

FC = 3
TC = 3
CC = 0
pH = 7.8 (added a little MA to drop it)
Hardness = 375 (store recommends 200 - 300)
TA = 85
CYA = 50

Does anyone know how to reduce hardness? Any help is greatly appreciated.

Thanks,
Shawn
 
Your hardness is on the high end of acceptable. Continued evaporation and refill could cause your hardness to climb if your fill water has significant hardness, so you could get too high. I would have your fill water tested to see if it is going to be an issue. If the fill water is low hardness, your pool's CH should drop naturally from rain water dilution.
 
I agree with John, as long as your other numbers are stable your CH should be fine.

What are you using to 'shock' your pool? Some shock products, esp some powdered forms contain calcium, one is "calcium-hypochlorite" and that can raise your CH number. So if by chance you are using that I wouldn't anymore, just shock with straight liquid chlorine a.k.a bleach.
 
It is my understanding with gunite pools that the exact numbers for your TA and CH are not as important as your CSI number. You can determine your CSI with JasonLion's PoolCalculator.

My CH was around 450 last year. It just takes a little extra vigilance when your numbers are on the high side to keep your CSI balanced.

I agree with the other posters, your numbers look fine.

Ron
 
Thanks all for the advice, I'll keep watching the numbers for a couple of weeks.

Frustratedpoolmom: I use liquid bleach to shock

John: I will get my fill water tested

Ron: I'll keep an eye on the CSI (that is new to me)

Thanks again all, have a great day!
 
All,
Hopefully someone will see this again. I drained my pool and it brought the hardness level
down but then a month later. The hardness is back up to 350 range. I tested my fill water
and it has a hardness of 200. So, not trusting the pool store on my hardness rising again,
I purchased the TF-100 test kit.

Got the TF-100 2 days ago and now my hardness level is testing at 700, 2 days in a row.

1. Can the hardness rise from 350 to 700 in a week? Pool store test on 8/4 was 350.

2. How can i keep my hardness from rising so much?

3. What am I doing wrong for with the test kit? Tested the fill water and it tested at 200.

Water is clear, but I am seeing a white water line on the tile, is this because of the hardness?
Any help is greatly appreciated.

Thanks,
Shawn
 
Is your pool store using a LaMotte colorimeter like the Waterlink Express and LaMotte reagents? there is a known limitation with this system when the CH is beyond the range of the meter and it will read low. Trust your results from the TF100.

Also, how new is your pool?
 
Texascajun,

I am in El Paso and struggle with Calcium Hardness as well, when I first started managing my pool myself 2 yrs ago, my CH was in the 700s, I did the drain and refill thing a couple of times, my fill water is about 200 CH as well, I have managed to keep it between 400 and 450. It is quite possible that the pool store test was wrong, and the TF 100 is right. I would rely on the TF 100, really I would rely on the walmart HTH tester before the Pool Store, IMO I don't think your CH could rise from 350 to 700 in a week, I think your CH has always been at 700. When I installed my SWG it would scale up in about a week, until I got the CSI under control, if you keep it within the range, you will prevent scale from building up. My CH is currently 450 and my SWG has been free from calcium build up for 6 wks now.
 
Waterbear,
sorry but i am not sure what the pool store is using to test my water, but they gladly sold me a $30 bottle of cleaner for the tile. Not going back anymore. Our pool is about 3.5 months old.

Rockcrawler,
Thanks for the help. I am trying to figure out this CSI thing, this is new so I don't quite understand it yet and how to control it. The pool calculater is saying that i should replace 57% of the pool water with new, wow, reads .96 csi.

I am starting to think that the CH has always been high, because this white water line just keeps coming back after i clean it with acid!

Guess I will have to drain again. Wow, did not expect this.
 
I am pretty use to running my pool at very high CH. I have very hard fill water (>350 pppm) during the summer so every year in February when fill water hardness drops to 50 ppm, I do a partial refill to bring the level down to 250 ppm or so. Last I measured CH it was north of 550 ppm. By the time next Feb comes around, it could be well above 700 ppm.

Because of the fill water, I decided some time ago to work with what I have rather than fight it. This is not too much of problem unless the PH gets high which can cause scaling. So I have an automatic acid feeder and try to keep the PH below 7.7 which seems to keep the scale at bay.

Bottom line is that you have find what works for you. It is a good idea to test the fill water during different parts of the year because depending on the water district and the water sources, the level can change significantly during the year. This way you know when the best time of year is for a refill. This should reduce the maximum CH that you might see during the year.
 

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texascajuns said:
Must be a water balance issue, cause i can not seem to control the pH, it bounces to 8.2 every 3 days, even though I hit with an entire gallon of acid, it will still be up there in a few days
Click to expand...
This is actually normal for new plaster (less than a year old)
 
You need to add acid more frequently to keep the PH from getting that high. If you continue to allow the PH to get very high you will almost always get calcium scaling which is rather difficult to remove.
 
My CH is 625 and has been for the last two seasons (that is when I started doing my own testing). I keep my TA between 70-80 to control the PH rise. I find with this I only have to add acid every couple weeks depending on how much evaporation I have to make up for. My fill water is 200ppm in CH and TA.

If you keep your TA lower you can easily manage this CH level though it is a little more work.

I have been running my SWG for two seasons now as well and there has been no scaling on it at all. I just checked three days ago.

With your TF100 in hand you should not have to worry about anything. You could do a partial drain if you wanted, but I just think that is such a waste of water.
 
I have a similar problem with CH and in addition to eliminating any calcium-based chemicals am doing my best to keep the pH correct. Without regular acid it gets up to 8.2 and scales pretty bad.
As far as cleaning a "bathtub ring", straight acid does the trick. You don't need any special product. I use a nalgene bottle of a type that is frequently used to dispense Iso Alcohol or other chemicals. It puts out a miniscule stream when squeezed and I can clean about 15 feet of tile with four ounces.
I am lucky to have a pretty competent / honest pool store and they carry a good product that helps with the typical CH white ring problem I have. It isn't unusual to lose half an inch or more water per day, so some ring is inevitable. Since using the original dose back in April and adding 3 oz per week, no ring!

I gave up fighting the hard water and between keeping my pH right and the additive, things have been lots better this season.
 
JasonLion said:
With CH around 700, I suggest you try to keep your PH below 7.8 at all times. With your numbers where they are now, you are very close to scaling.
Click to expand...


Jason beat me too it, that is the only way to keep that white line from appearing, no matter what you have to do, even if you have to add acid everyday, keep the PH below 7.8
 

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