Knocking CH Out of the Park

[aerospa]

Hi, my TF100 arrived yesterday and here are the numbers:

FC - 3.0
CC - 0.0
PH - 7.6
TA - 70
CYA - 40
CH - 1100

Yep, 1100. It took 40 drops. I did it twice.

My fill water CH is 200 (phew), so in searching the forum it seems the "solution" would be a substantial drain and refill. In the meantime I am one of the privileged few who must, according to TFP, keep an eye on CSI. However I don't seem to be having any problems. The pool water is very clear. There's a little bit of white scaling on the blue tiles here and there, but I was ignoring it figuring I could clean it off with some elbow grease or a pressure washer.

1. I just bought this house/pool. I haven't added anything but 12.5% bleach, sodium bicarbonate, cyanuric acid, and muriatic acid. So I assume I inherited this problem rather than created it. With a fill water CH of 200, how did the pool end up at 1100? What do I need to avoid doing to end up in this situation again?

2. Is it possible that my fill water CH varies throughout the year? There's a water softener hooked up to the house, but it is being bypassed right now via the valve. It had been like that when we took the place over.

3. Pool Math says my CSI is 0.2, and it also says that's a fine number. Should I be managing this number, and if so to what range? That I can tell, lowering pH or TA and raising CYA have the effect of lowering CSI. I assume the opposite actions have the opposite effect. 0.3 CSI seems to be the upper bound of "looks good", whereas -0.6 is the lower bound.

 

[Rancho Cost-a-Lotta]

Ideally, you should run your CSI in the negative range, between 0.0 to -0.30. This will reduce that chance of calcium scaling.

Your CH is real high. The two primary sources for calcium in a pool are cal-hypo sanitizer and fill water. Calcium, once in the pool, doesn't leave with evaporation. As fill water is added, more calcium is added (in your case at a rate of 200 ppm) and it continues to build. The only way to reduce calcium is a water drain or exchange. Since your fill water is 200, you need to replace nearly all the water. CH levels may vary during the year depending where your provider gets water from. Test your fill water every few weeks. You can find your provider's water quality report online that should include a range/average of CH levels.

As for the waterline scaling, you can try to remove with diluted MA and a lot of elbow grease. There are other chemical options linked in the thread below. I ended up having my scale remove via media blasting. I've since maintained a negative CSI and so far, things look good.

Waterline Scale Removal

After a recent drain and refill and dialing in my chemistry and CSI, I'm ready to have the waterline calcium scale removed. I now understand how to avoid calcium deposits so I'm ready for a nice clean start. As I start my search of local vendors, I thought I would seek input that may help me...

www.troublefreepool.com

 

[Rancho Cost-a-Lotta]

I forgot to mention...You'll lose 1/4" or more per day during the warmer months to evaporation. If can get your water softener hooked up for top-offs, you'll greatly reduce the frequency of water exchanges.

 

[aerospa]

Thank you for your quick and thorough response, Rancho!

Calcium, once in the pool, doesn't leave with evaporation.

That's a shame but it makes sense.

We need to have some tile work done on the pool, and maybe a total replaster (pool built in 1993, no update since then) in the next couple of years, so I'd like to try to manage the condition until then instead of a full drain/refill.

My plan:

1. Bring pH down to 7.4, let TA come down a bit with it, to bring my CSI to 0 according to Pool Math. I'll have to see if/how this balances out.
2. Look in to getting my water softener activated. I'll need to balance the price of energy consumed by the softener with the price of water in just doing a drain/refill. I have no experience with water softeners.
3. Install a hose bib on the pressure side of the filter pump plumbing so that I can water the backyard off of pool water and then replenish the pool out of the tap.

Question: pH 7.4 is below my Pool Math target of 7.6-7.8, but above the lower limit of 7.2. Should I be careful to watch for anything as my pH goes below the acceptable range.

Also, Pool Math tells me there's some very weak gains to be had by increasing CYA (-0.03 CSI per 10 pmm CYA). Any value in bringing my CYA up?

Thanks again!

 

[Rancho Cost-a-Lotta]

Sounds like you got it figured out. Keep your CSI and close to 0 as you can. There's no issue with running your pH at 7.4. Continuing to knock down your pH with MA will also drop your TA, which will help your CSI. Raising your CYA is good up to 60, but you may want to reserve this buffer for use of trichlor tabs when you're away or unable to dose.

 

[Rancho Cost-a-Lotta]

2. Look in to getting my water softener activated. I'll need to balance the price of energy consumed by the softener with the price of water in just doing a drain/refill. I have no experience with water softeners.

Matt, @JoyfulNoise, might be able provide guidance on the water softener (or any other topic for that matter).

 

[JoyfulNoise]

Water softeners don’t use energy. The control valve is electronic but you’re talking about a few watts of power to run it. A good modern softener uses about 25-30 gallons of water for the regeneration cycle and about 6-8lbs of salt per regen. A properly sized water softener should give you a minimum of 3-4 days between regenerations during heaviest use periods.

 

[aerospa]

Water softeners don’t use energy. The control valve is electronic but you’re talking about a few watts of power to run it. A good modern softener uses about 25-30 gallons of water for the regeneration cycle and about 6-8lbs of salt per regen.

Ah, I knew I was paying for something, I just figured it was for electricity. Hopefully the economics of the water softener work out.

I did some math, and if I assume I have to fill my pool in the top tier of water cost then it would be $114 to drain and refill. That doesn't seem too bad if I don't have to do it except once in a great long while.

Thank you @JoyfulNoise and @Rancho Cost-a-Lotta for lending me your expertise, I really appreciate your time.

 

[Rancho Cost-a-Lotta]

Avoid products containing cal-hypo and trichlor and you should be able to stretch it out a bit. Hopefully your water provider obtains water from different sources throughout the year. Take advantage of calcium-free rain when you see it coming. Since December, we've had about 16-18" of rain. In my pool that equates to about 25% of my pool volume.

 

[triptyx]

Just to wade in as someone that deals with fill water in the 225-250 range, you can certainly maintain your pool at that CH level. As you said, you'll want to get your TA down, and keep your pH 7.2 to 7.4. 7.2 is perfectly ok, just don't go below that. Watch the CSI as the water warms - it will go up!

I drain about every three years due to runaway calcium levels - here in Southern Arizona, our low humidity and high heat makes for a mess of evaporation.

 

[JoyfulNoise]

In Tucson and most of the southern AZ region, we get about 10” of rain per year (if we’re lucky) and around 100” of evaporation per year. So, for most pools, that’s about the entire pool volume of water evaporated away. Depending on the source water CH, you can expect the CH in a pool to increase each year in the 200-300ppm/year range. Water softeners reduce that rate of rise to nearly zero.

 

[aerospa]

I drain about every three years due to runaway calcium levels

Depending on the source water CH, you can expect the CH in a pool to increase each year in the 200-300ppm/year range.

Wow that's crazy! Hard water makes pool care less fun for sure.

Well a bit of unfortunate news for me tonight. On a hunch I went crawling under the house to look at the plumbing, and sure enough the pool fill valve is fed off a cold water line that bypasses the water softener. Not that it couldn't be rearranged to run off softened water fairly easily (as far as plumbing projects go), but maybe the first thing is to activate it and test the hardness from an interior tap. If it doesn't work or needs maintenance, I'm not going to spend $1,000-$2,000 on a new unit - that's a lifetime of pool refills at today's prices.

Even so, my first glance at salt prices and estimated salt consumption makes me think that a drain/refill every X years might balance with the cost of salt. Going to have to look more into it, as well as my softener's capacity.

 

[ping]

When my pool's CH gets to 800 I drain and refill because it is a pain to have to monitor the pool that close to keep it from scaling. In the summer when I'm adding a couple inches of water every week it is also hard to keep the TA down so the pool needs more acid to prevent the CSI getting out of range. It's worth it for me to spend $150 on water and chems to balance the water and not have to worry about scale. My pool seems to increase on average 150ppm of CH a year.

 

[JoyfulNoise]

Wow that's crazy! Hard water makes pool care less fun for sure.

Well a bit of unfortunate news for me tonight. On a hunch I went crawling under the house to look at the plumbing, and sure enough the pool fill valve is fed off a cold water line that bypasses the water softener. Not that it couldn't be rearranged to run off softened water fairly easily (as far as plumbing projects go), but maybe the first thing is to activate it and test the hardness from an interior tap. If it doesn't work or needs maintenance, I'm not going to spend $1,000-$2,000 on a new unit - that's a lifetime of pool refills at today's prices.

Even so, my first glance at salt prices and estimated salt consumption makes me think that a drain/refill every X years might balance with the cost of salt. Going to have to look more into it, as well as my softener's capacity.

Depending on the age of the unit or who installed it, it could potentially just be serviced. Usually you need to change the ion exchange resin every 5 years or so. Some units are serviceable like that. You'll need to check with the manufacturer or an honest plumber to see what is needed.

 

[aerospa]

When my pool's CH gets to 800 I drain and refill because it is a pain to have to monitor the pool that close to keep it from scaling.

Yes it seems that a drain/refill is inevitable for multiple reasons for me.

You'll need to check with the manufacturer or an honest plumber to see what is needed.

Yes I plan on doing so. We've been living without the water softener for a couple of months now and things have been fine. Didn't have one at our old place where the water was the same. Maybe I can hook up the water softener to the pool only and bypass the rest of the house...

 

[JoyfulNoise]

Yes it seems that a drain/refill is inevitable for multiple reasons for me.


Yes I plan on doing so. We've been living without the water softener for a couple of months now and things have been fine. Didn't have one at our old place where the water was the same. Maybe I can hook up the water softener to the pool only and bypass the rest of the house...

We lived for many years without a softener and when we switched I had forgotten how used to hard water I had gotten. I grew in NY on Long Island where the well water is extremely soft (little to no calcium at all). Eventually I landed up in California (fun, but did not want to live there) and now southern AZ. I just got used to the fact that the calcium in the water reacts with the soap on your skin and forms calcium and magnesium stearate; that's the squeaky, rough feeling you get. You think your skin is clean but, in actuality, you're leaving behind thin layer of precipitated stearates. Same thing happens in the laundry although modern detergents are heavily loaded with chelating agents to hold the calcium and magnesium in solution. Our faucets crusted over with scale all the time and we just dutifully soaked things in vinegar to remove the crust. I can only imagine what is in the bottom of my hot water heaters but I hear the boiler cakes created in this part of the country are something to see.

After we got our softener, I couldn't believe how silky water can feel on your skin when you're not getting loaded down with calcium. I also had to learn to use less soap and shampoo as a little bit goes a very long way when there's no calcium hardness. I use half the amount of detergents now in my washer and dishwasher. My clothes and towels feel and smell a lot better when there isn't gunk getting caught up in the fibers. The down side is that you can't drink the water out of the tap (excess sodium leaves a slightly salty/bitter taste) but the fridge has a filtered cold water tap and it's not on the softener loop. One of these days I'll get around to installing an RO water tap at the sink.

Personally I think softeners are a good investment as they reduce a lot of wear and tear on the more expensive things in a home like water heaters and dishwashers. But, it's a personal choice...to each his own.

 

[aerospa]

Same thing happens in the laundry although modern detergents are heavily loaded with chelating agents to hold the calcium and magnesium in solution.

This is really interesting, I did not know this.

Personally I think softeners are a good investment

That was particularly insightful and it sounds like a nice quality of life improvement. I'm going to get the softener going and see how it goes.

Edit: Oh, and I looked up the water quality test reports from my water provider. Here are the hardness ranges and averages:

2018: 84-274, 181 avg.
2017: 87-306, 222 avg. (kinda strange it's the exact same numbers as 2016)
2016: 87-306, 222 avg.

 

[JoyfulNoise]

Edit: Oh, and I looked up the water quality test reports from my water provider. Here are the hardness ranges and averages:

2018: 84-274, 181 avg.
2017: 87-306, 222 avg. (kinda strange it's the exact same numbers as 2016)
2016: 87-306, 222 avg.

That’s considered hard water. Most utilities measure general hardness (GH) which takes into account calcium and magnesium hardness. However, the vast majority of the hardness is from calcium and, for most terrestrial water sources, the ratio of calcium to magnesium hardness is about 6:1. Since your averages are closer to your max value, you probably rarely get water that’s below 100ppm CH. Without a water softener, your household fixtures will build up scale over time and any drinking glasses will show spots and “fogginess” after being run through the dishwasher. Even with rinse aids and detergents formulated for hard water, my drinking glasses always had a haze to them and my dishwasher needed to be rinsed with a cleaning agent (Lemi-Shine works well) every few months or else the inside steel walls would be dull and crusted in spots. Water hardness really takes a toll on appliances. I only use soft water (distilled) in my coffee maker but I have ruined a few coffee makers in my past by using tap water.

I spent close to $2000 on my softener setup but I had to pay extra for the hook up to the pool line (it was buried about 2ft down and it took two guys a few hours to trench it out) and I also got the largest softener available, 52k grains. Mine is also a dual-eliminator system with a granular activated carbon (GAC) filter to remove chlorine/chloramines from the water. Even though it cost a lot of money, I would totally do it all over again. It was worth every penny it cost me.

 

[aerospa]

I had to pay extra for the hook up to the pool line (it was buried about 2ft down and it took two guys a few hours to trench it out)

This is where I got lucky. All of the copper plumbing is exposed in the crawlspace under the house. In fact, it looks like it used to be plumbed so the pool filled off the softened water.

My concern is my water softener is old - probably 90's vintage - and is likely not as efficient as a modern unit in terms of water and salt.

 

[tanksjeep]

Matt's water softener install got me motivated and I just finished installing my WS for pool make up water. It is dedicated to the pool and I have another one for the house. Here in Havasu, the evaporation is even worse than what Matt sees. We are hotter here. Water is cheap here and I used to drain the pool every other year (some drain their pool every year) but my CH would be more than double (~800) by the end of summer and then the following summer would be ~1200 or more. Prior to installing the WS, I drained the pool to get a baseline of 375 so we'll see what it is at the end of summer. May be around 400-450 since I'm guessing some of the CH will dissolve off of the tile/plaster...not sure.

Thanks again Matt for your help!