CH Levels and New Plaster/Pebble

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B

bacevedo

0
Apr 14, 2013
153
Chandler, AZ
We had our pool completed last year, so this is the first full season that we have had it. I'm having some issues with high CH and wanted to ask some questions on my options.

In the last few weeks, I have noticed the "snow" flakes in the pool, which I am pretty sure is due to my CH level being about 650-700 and my pH about 7.8. Here in AZ, our water is very hard, so I knew my CH levels would be high. My other levels are fine on my salt water pool:

FC: 3
CC: 0
Salt Level: 3500
TA: 90
CH: 650-700
CYA: 40 (I know this is low, will be adjusting higher later)
Water temp: about 94 degrees

I was on vacation for a couple of weeks and had a friend coming to add acid to the pool, but I'm not sure if the pH ever got above 7.8. When I got back, I noticed the flakes and at first thought my DE filter had a tear and was letting DE into the pool. After investigation, I found it was the flakes from high CH and possibly high pH. I am thinking about draining my pool at the end of this swimming season and filling with fresh water. I know that's the only way to lower my CH.

I have been adding a lot of acid (2 cups, 29% MA) to try to lower my pH, but it seems to jump right back to 7.8 in a day or two. I don't want to have to add 2 cups of acid every day or every other day to control this. pH of 7.8 is a reasonable goal, but with CH so high, I probably really need to be at 7.5. but it's too difficult to get to that level.

So my question:
Could my high CH be due to new plaster/pebble? Now that the pebble has had time to "settle/cure" could my CH rise more slowly from the fill water and evaporation? I don't want to have to drain and refill every year to keep my CH in check.

How do others in AZ (specifically SE Chandler) deal with our hard water? Do you just drain and refill? How often?

Thanks for any help!

Bryan
 
I don't want to have to add 2 cups of acid every day or every other day to control this. pH of 7.8 is a reasonable goal, but with CH so high, I probably really need to be at 7.5. but it's too difficult to get to that level
Click to expand...
The problem is I can't think of an alternative. High pH is high pH and it has to be lowered. Muriatic acid is the best way to do that..

Your next step should be to test the pH and CH and TA of your fill water so you know what you are putting in your pool. Post those up and we'll help figure a plan.....not a perfect one for sure but a plan that you can probably live with.
 
The pH is less of my concern. I can add acid to control it. I'm more concerned with my high CH and the snowflakes in the pool. I haven't changed anything (same amount of acid, levels, etc.) and they appeared one year in, so I assume that my high CH rise is really the problem. If I can drain and refill, but have the new water last me a little while longer (like 2-3 years) then that is a better solution to me. I have heard many people in AZ say they drain and refill their pools every couple of years, but I suspected that was more from high CYA (using pucks) and not CH. In reality, it may be both and I'll still have to drain even if my other levels are fine.

I'll take some measurements of the tap water and report back.

But my other question remains - does new plaster\pebble cause a high rise in CH for the first year or so due to it settling in or would it not impact it that much?
 
Draining the whole pool every year or two because of high calcium levels is quite common in Arizona. If your fill water CH levels are fairly high, common in AZ, you have little choice other than keeping PH tightly controlled.
 
Hmm this makes me want to re-test my fill water. I'm a little south down in Oro Valley near Tucson and when I tested my fill water it barely had any CH. I think it turned in 1 or 2 drops. The CH in my pool was 350 when I first started the TFP method and was 325 when I checked a couple days ago so not using shock and doing a few backwashes seems to have lowered it. But like you I also have problems with pH rising. Mine rises about 0.2 a day so mine drinks like 8 ozs of acid a day.
 
It is more likely that evaporation is the primary reason for CH increasing.

Are the "snow" flakes floating on top of the water, or are they on the bottom of the pool?

Your Salt (or TDS) level is high, does that mean your pool has a salt water chlorine generator? If so, flakes on the bottom of the pool may be coming from your Salt unit.

If no SWCG, I still don't think that the high CH is causing snow flakes to develop, as there is probably something else involved.
 
Yes, I have a SWCG and just cleaned it a few weeks ago. The flakes are floating on the bottom of the pool and I suspect they were from my salt cell, just as you have said.

It's possible these flakes are just leftovers from the original problem and they were still floating/suspended in the water when I vacuumed out the others. We've had several dust storms in the last few days and I haven't wanted to vacuum because I would just have to do it again the next day.

My real question I guess, is does a new pebble pool cause CH levels to be high with the first fill of water? Does the plaster leach any calcium residue into the water and if I drain and refill, my CH levels won't get so high so fast because the plaster is done giving off excess calcium.

For any other info on my pool, you can see my sig and pool build thread.

Edit: I just tested my fill water and CH out of the tap as 200-230. It was hard to tell which exact drop turned it to blue on my TFT-100 test kit. But it was in that range.
 
I missed the SWCG reference in your sig.

The first initial filling of the pool can result in the CH increasing somewhat, probably about 50 ppm to 100 ppm at the most.
But now that the plaster has cured more, a drain and refill should not result in the same amount of increase in CH.

But one thing you may not be aware of is that some pool builders will fill a pebble pool and then do a No Drain acid wash to help expose the color aggregate. If that was the case, then the CH could/would increase as much as 300 ppm.

Edit: A high CH (WITH A SWCG) will result in snowflakes (calcium carbonate flakes) that eventually ends up in the pool.
 
Thanks for the feedback onBalance.

Our pool had a regular acid wash before it was filled so that won't be an issue for us.

It sounds like I'll probably just have to drain and refill every 1-2 years to keep my CH in check. I have heard that it is routine in AZ to empty and refill your pool every couple of years because "the water gets out of whack." I figured it was from people who didn't know how to properly balance their pool or were using chlorine pucks and their CYA got too high. One of the reasons I chose a DE filter over a cartridge filter was because I was hoping a backwash would refresh my water enough that CH wouldn't climb so high, so fast. But only backwashing 1-2 times a year probably doesn't offset that. I guess I could backwash more often, but I suspect I'll still need to drain.

For now, I'll just keep adding acid every day to keep my pH in the 7.5 range until we are done swimming (probably not until October) and then I'll drain it. Over the winter, my SWCG and filter didn't need to run so much, so my pH didn't climb as much as it does now. With it warming up and the dust, the filter and SWCG are running a lot more. I guess the easy maintenance in the winter spoiled me! :)

Thanks everyone!

- - - Updated - - -

duraleigh said:
The problem is I can't think of an alternative. High pH is high pH and it has to be lowered. Muriatic acid is the best way to do that..

Your next step should be to test the pH and CH and TA of your fill water so you know what you are putting in your pool. Post those up and we'll help figure a plan.....not a perfect one for sure but a plan that you can probably live with.
Click to expand...

I tested my CH and pH of my fill water. I didn't test TA, but my TA doesn't seem to drift too much from 80-90. I did get down to about 60-70 and I easily brought it back up to 90.

CH is 200-230
pH is 7.2
 

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I've been watching threads like this waiting for someone to find the solution to keep pH from rising so fast. I've seen several of us in this situation. Also I'm in AZ so I was curious about the comments on CH. I hadn't heard of anyone I know refilling their pool every couple years. But if your fill water is what's causing the CH to rise it would do no good to drain and refill unless you are getting the water trucked in from a source with low CH.

Our Oro Valley water in AZ seems really good. I retested last night and it was just barely pink and turned blue in 1 drop for the CH test so not sure if I call that 25 but its really low. pH was 7.2.
 
My pool water is anywhere from 400 to 500 ppm CH. I have no issues with snowflakes (banging my head on a wooden desk just to be safe). Tucson water supplies our municipal water and it's never any better than 250 to 280 ppm. My pool builder told me that he's seen crystal clear pools with CH's up in the 1200ppm range.

Did your PB follow the proper startup procedure for filling a pool when it has been resurfaced (detailed in PoolSchool)? Not properly starting up a newly resurfaced pool can load the water with CH. Yes, a plaster or pebble pool will have higher CH due to the curing cement. But if the proper startup procedure is used, then it shouldn't be too bad.

Also, as far as DE back washing goes, you can always backwash longer to remove more water. That can help maintain you water a little better.


Sent from my iPhone using Tapatalk
 
Gilrock said:
I've been watching threads like this waiting for someone to find the solution to keep pH from rising so fast. I've seen several of us in this situation. Also I'm in AZ so I was curious about the comments on CH. I hadn't heard of anyone I know refilling their pool every couple years. But if your fill water is what's causing the CH to rise it would do no good to drain and refill unless you are getting the water trucked in from a source with low CH.

Our Oro Valley water in AZ seems really good. I retested last night and it was just barely pink and turned blue in 1 drop for the CH test so not sure if I call that 25 but its really low. pH was 7.2.
Click to expand...

Id love to install a Pentair IntelliPH system on my pool. It would allow for a more regular dosing of the water with MA. I feel like my pH is ok but I'd rather maintain it slowly with small regular additions than just using a big slug of acid every few days or so. One more expensive pool toy for the list...


Sent from my iPhone using Tapatalk
 
Well the light bulb went off and I realize why you could reduce the CH with a drain/refill. The CH would continually rise due to evaporation and the drain/refill would at least bring the CH level back down to the level of the fill water.
 
I think we have things under control now. I just did some tests about 3 hours after the automated pump turned off (about 3pm AZ time).

FC: 8 (High because Salt Cell was just turned off 3 hours earlier. By this evening, it should drop to 3-4 with the AZ sun)
CC: .5 (might actually be 0 because I may not have added enough drops for the FC test)
pH: 7.6 (Added 6oz 29% MA to bring it down to 7.5)
TA: 80
CH: 700 (didn't retest this, but still assuming around this range)
CYA: 35 (right in the middle between 35-40 - this one is hard to get exact)
Salt: 3600
Temp: 92
CSI: 0.26

I'm still seeing some bigger snowflakes (calcium chunks) coming out of the spa return, so I think I'm going to clean my salt cell again. I'm guessing it got dirty again with my pH being a little high earlier. Now that I have my pH down in the 7.5. range, it will be easier to keep it there. It just took some time for me to get it closer so it would stabilize and not require the large amounts of acid each day.
 
I need to clarify one thing about calcium flakes and SWCG; even pool water with lower CH levels and balanced pH can still create calcium flakes over time.
You might consider lowering the TA a little to help minimize the pH rise. But there isn't a good and simple way to stop the pH from rising altogether. It is the nature of the beast.
 
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