Cause for CH Increases

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bxcrwlly

bxcrwlly

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LifeTime Supporter
Dec 3, 2012
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Central Florida
Weeks ago, my CH registered at 250. Today it registered at 425. Obviously I want to get it back in the normal range of 250-350. I'm wondering what is causing this gradual rise. Are there other chemicals (I'm using the BBB method) that is causing this rise? Can CH be impacted by water temp changes ie. low to high? My outside source water is at 300 (originally filled using home water filtration) which measured at 25ppm. Pool was drained to about 40%, then refilled. That's how I started at 250. I haven't added much water since it originally checked at 250. Any assistance is appreciated.
 
Confirmed today with pool store, that their CH test of my water, is within 50ppm of my test. Since draining requires more salt, borax and stabilizer and obviously water, I'm thinking of trying one of the CH reducer products to offset some of the expense. Pool store rep advises my high CH is probably resulting from the acid wash(es) I had performed 2 months ago. Use only liquid chlorine or bleach to raise FC. No Cal Hypo.
 
Jason...I read a number of articles regarding CalTreat. While I haven't done any scientific analysis of positive v. negative results, I'm thinking it might be worth a shot. I can always resort to draining and refilling.
 
Have been doing a lot of reading on calcium reduction. Found another product that was manufactured specifically for hot tubs/spas to reduce calcium from salt generating systems. If the testimonials are any indication, it works to significantly reduce CH in hot tubs and spas. Granted, I'm dealing with a significant amount of water but only need to reduce my CH by 50 or 75ppm. I'm going to give it a try. Will post my results.
 
Thanks Richard....just trying to maintain pool against TFP standards for SWG pool. CH=250-350, so I was shooting for a midpoint of 300. I get nervous when CH gets above 350 since we just emerged from an acid wash (twice) to remove "alleged" hydration stains. We removed a large amount of calcium deposits in the process. Just trying to keep everything in check.
 
I agree with Richard that your current CH level can be managed quite easily. Just keep testing it regularly to ensure it does not continue going up. Post a full set of results if you want.

I am not aware of any calcium reduction products that have a proven track record. Which one are you looking at?
 
Looking at CalTreat by United Chemicals and a product called Vanishing Act(For Spas) by Watkins marketed under the brand Hot Springs. It seems that a number of products are manufactured in Australia due to their water restrictions/hardness issues; however most can't be imported to the U.S. I also discovered an article discussing "Lime Softening" that can be used to dissipate calcium out of pool water; thereby reducing calcium hardness. While it doesn't appear overly complex, there is some work involved to invoke the process and extract the dissipated calcium from the pool. The article provides a "test" scenario that can be used before actually trying it on a pool. I can attach a link to the article if there is any interest.
 

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bxcrwlly:

CH levels will tend to increase over time due to evaporation & adding tap water to maintain the proper water level. The water evaporates but the calcium does not. Most tap water has some calcium in it, so calcium is being added with each top off. With that said, going from 250 to 425 ppm in a matter of weeks seems a bit extreme based solely on evaporation. In any event, a CH of 425 is not something I would lose sleep over. Follow Richard's advice on adjusting pH & TA to keep CSI slightly negative (refer to Pool Calculator to calculate CSI based on your test results).
 
From what I've read on new plaster startups (mostly written by onBalance) I think your pool store is likely correct on the cause for the calcium rise. It would appear the acid washes have caused some of the calcium in your plaster to be pulled into the water.

I have no knowledge or comment on how, or even if, you should do anything about the calcium readings. Were calcium levels thought to have been a contributing factor to your previous problems?
 
Richard....so I have to ask. If TFP recommends 250-350 CH (as standard), and as you noted, your CH was never as low as mine (previous test 425), now(4/17/13) tested at 500, what is the critical upper limit for CH? I'm trying not to make a mountain out of a mole hill; however, having trouble understanding if/when I should worry about keeping it in the TFP recommended range. Yesterday 4/17, I dumped 11 inches of water trying to reduce CH. Will check level today. I wonder if my no-drain acid wash is having a negative effect as Terry noted above. Appreciate your guidance.
 
The values that we give as within range (250-350 ppm) on CH is assuming that everything else in your pool (ph, TA, temperature, etc.) has values that fall within a certain set of parameters. I would suggest reading the following sticky about calcium scaling so that you are able to get a grasp on CSI (not the TV show, but the calcium saturation index). After reading it, you should be able to follow our position on CH values a little better and understand why we can't really give a maximum number that works for all pools. :goodjob:

pool-school/calcium_scaling
 
There is no critical upper limit. Things just get more problematic as CH increases much above 350.

It's all about pool water management. CH, pH, and TA are the influencing factors and, as your CH increases, pH and TA have to be more carefully controlled.

Richard320 has managed his pool with great skill (and a good sense of humor) as I think his CH may have started around 800 or so, I can't remember.

So you won't have a solid brick of Calcium if your CH moves above 400 nor will you be bulletproof with a CH of 200. TFP offers all of our guidelines as suggested limits but they are guidelines and not absolutes.
 
Thanks guys for both responses. I've been maintaining my PH and/or ALK(actually reduced ALK to 50 to try and limit PH rise) with TFP standards and will continue to to monitor CH. I was using 25 ounces of MA every other day to control PH to 7.5. Jason suggested on another post to let PH rise to 7.6 or 7.7. I've done that. MA consumption reduced to about 8-9 ounces DAILY to maintain 7.6 or 7.7. Prior to my no-drain acid wash, my PH was fairly stable. Will worry less about CH and continue focus on PH and TA.
 
Alrighty then. Here's my CSI readings since 3/24. See file below message. Days missing simply means I checked but didn't record. Usually test daily or worst case every other day.

Looks like I'm within standard variance except for 3/24, 3/26, 3/27 & 3/30. Also all negative except for today. That will change account lowered PH to 7.0 to get a drop in TA from 100 to around 70/75. So according to the guidance in the above 4/18 responses, I'll continue to maintain CSI within -.6 to +.6 and even though CH may rise outside of "traditional" standards, I should be o.k. Am I reading the feedback correctly?
 

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