First tests with proper test kit; and is it time to replace some water?

[dailygenesis]

Hi all,

New pool owner as of July 2022. In other threads, some members advised me to get a proper test kit and to come back with any questions at the time. Well, now is the time and I do have a few questions.

First, my test results using my new TF-Pro, which is so great...

FC: 4.0
CC: 0.5
pH: 7.4
TA: 70
CH: 575
CYA: 90
Water Temp is currently around 47 F

I also tested my water source with the kit and found it to have...
CH: 200
CYA: 0

My CH and CYA levels are most concerning to me right now. I have been using a tablet feeder for chlorination since the pool was new in July, but after reading more about that here and hearing from some of you, I have stopped using tablets and have switched to liquid chlorine to avoid putting any more CYA in the pool.

I know everyone here has advised I should look at eventually switching to an SWG, but assuming that's a bit down the road for me, I'm looking for steps I can take now to get things in line.

My first thought is that I should attempt a partial water replacement -- something I haven't done before. I have been reading about the No Drain Water Exchange here -> Draining - Further Reading -- and I think I could pull that off sometime in the next week.

My thought is to replace 50% of my water. This should bring the CYA down to around 45 and CH to around 375. Those seems like good targets to hit to sort of reset everything, but I'm wondering if there's anything else I should consider before doing this.

@Dirk you were one of the biggest encouragers for me to get to testing, so tagging you here to see if you have any thoughts.

 

[PoolStored]

My first thought is that I should attempt a partial water replacement -- something I haven't done before. I have been reading about the No Drain Water Exchange here -> Draining - Further Reading -- and I think I could pull that off sometime in the next week.

^^This. Go.

 

[PoolStored]

My thought is to replace 50% of my water. This should bring the CYA down to around 45 and CH to around 375.

 

[Dirk]

Hi all,

New pool owner as of July 2022. In other threads, some members advised me to get a proper test kit and to come back with any questions at the time. Well, now is the time and I do have a few questions.

First, my test results using my new TF-Pro, which is so great...

FC: 4.0
CC: 0.5
pH: 7.4
TA: 70
CH: 575
CYA: 90
Water Temp is currently around 47 F

I also tested my water source with the kit and found it to have...
CH: 200
CYA: 0

My CH and CYA levels are most concerning to me right now. I have been using a tablet feeder for chlorination since the pool was new in July, but after reading more about that here and hearing from some of you, I have stopped using tablets and have switched to liquid chlorine to avoid putting any more CYA in the pool.

I know everyone here has advised I should look at eventually switching to an SWG, but assuming that's a bit down the road for me, I'm looking for steps I can take now to get things in line.

My first thought is that I should attempt a partial water replacement -- something I haven't done before. I have been reading about the No Drain Water Exchange here -> Draining - Further Reading -- and I think I could pull that off sometime in the next week.

My thought is to replace 50% of my water. This should bring the CYA down to around 45 and CH to around 375. Those seems like good targets to hit to sort of reset everything, but I'm wondering if there's anything else I should consider before doing this.

@Dirk you were one of the biggest encouragers for me to get to testing, so tagging you here to see if you have any thoughts.

I would wait. Temperatures are cold. You won't be needing much of any chlorine, and it won't be burning off in the winter like it would in the summer. CYA helps protect your FC level from the sun, but if the sun is low in the sky, and daylight hours are short, the level of protection needed goes down. Plus, CYA dissipates over time. You might find a much lower level of CYA in the spring, and so need much less of a water exchange.

I would encourage the no drain exchange if that can work for you. But that type of exchange uses more water, which is another reason to see how low the CYA will get on its own.

The other reason to wait: you need to know if your local municipality determines your sewer rates based on water consumption. Mine does so in the three winter months we are currently in. They figure no one waters their garden in the winter, so all the water used is inside the house, and ending up in the sewer. Now is not the time for me to add any water to the pool that I don't need to. Do you know if that's the case in your area?

And then there's the rain. If you get a lot, you can manipulate the water level in your pool to take advantage of the "free" water exchange rain can provide. I'd need to know more about your pool to advise you how that's done, but again, that could be another reason to wait on the exchange.

Your levels look good. Great job getting the kit and posting. Exactly what we like to see. Your CYA and CH are high, but not off the chart. I don't see a pressing need to exchange water next week, but several reasons not to. Your FC should be above 7 (based on your CYA). If you don't have trouble maintaining 7+, then waiting on a CYA solution is fine.

And lastly, a very obscure reason: I'll be doing a write up about my recent water exchange adventure that might have some ideas you can use. Hopefully I'll get that posted in the next few weeks.

 

[mgtfp]

I'll be doing a write up about my recent water exchange adventure

I can see a featured article coming...

 

[Newdude]

+1 with Dirk. We advise alot of folks to wait out the end of the season and let the winter months help the process. CYA degrades about 5ppm a month on its own and the rain will help some too. For folks getting started in the early spring it's too far away, but we're here now so you might as well use it to your advantage.

 

[HermanTX]

And then there's the rain. If you get a lot, you can manipulate the water level in your pool to take advantage of the "free" water exchange rain can provide. I'd need to know more about your pool to advise you how that's done, but again, that could be another reason to wait on the exchange.

+1 on this method. I have used it several times in the late Fall and early Winter months. If big storm coming through, I drain to a couple of inches below tiles, let it fill back to bottom of tile or higher depending on the rain, then wait for another rain storm to continue to fill. You do not want to expose your plaster to a lot of sun so drain your just below the tiles so you know that the pending rain storm will fill it back up to at least cover the plaster again. In Fall & Winter you have less risk of plaster damage due to low angle of sun and cloudy days. I did this for several rain storms over couple of months and successfully got down to 40 CYA.

@dailygenesis - great work on testing. I lived with CYA 90 for several months down in TX when I first converted to LC and it is manageable. Hope you can find good supply of LC. I recently converted to SWCG but like you, I managed with LC for several years before jumping to SWCG.

 

[dailygenesis]

Thanks to everyone for the replies. I had thought about waiting for some of the reasons mentioned (my utilities work the same way @Dirk -- I think it's Dec-Feb but I need to check).

My biggest concerns on waiting were

1. CH level -- but it seems like maybe that's still within acceptable range so no harm in waiting? At what point would I need to be concerned about this being too high and causing issue?
2. Chlorine requirements with such a high CYA -- is it recommended to maintain the same FC levels all winter even with water below 50 degrees?

 

[Newdude]

My biggest concerns on waiting were

1. CH level

Ch is barely above range and fine. With high fill water you'll be increasing it when the pool is evaporating alot, but it should be much less for the winter.

Chlorine requirements with such a high CYA -- is it recommended to maintain the same FC levels all winter even with water below 50 degrees?

It is always reccomended to stay above minimum for your FC. But the good news is that the daily loss is slim to none these days so once you're where you need to be, it will be alot easier to maintain than it would be in the peak season.

 

[HermanTX]

CH level -- but it seems like maybe that's still within acceptable range so no harm in waiting?

many people in AZ and NV have high CH and manage it well. Whenever you drain then CH will decrease.

Chlorine requirements with such a high CYA -- is it recommended to maintain the same FC levels all winter even with water below 50 degrees?

You only need to use more LC to bring it up to the proper range. Then the daily consumption is based on your daily FC loss - which at this time of year is very low - maybe 1-2ppm of FC. So your LC use once you are in range is minimal at this time of year.

 

[Dirk]

I've been away for a few days, but I see you've been in good hands. I think everything got covered.

1. CH level -- but it seems like maybe that's still within acceptable range so no harm in waiting? At what point would I need to be concerned about this being too high and causing issue?

Have you dabbled with CSI yet? That's the number you want to keep an eye on. You can get away with an elevated CH by reducing some other factor to keep your CSI in check. Typically that is pH. Do you have the Pool Math app? Have you played with the calculators? There is one for CSI. You can enter your levels to get your CSI number. Ideally it should be 0 for a non-SWG pool, but anywhere between -0.3 and +0.3 is fine. If you play with the calculator, you can see what lowering you pH does to your CSI with a CH of 575. Give it a go. You'll also see a big difference when you play with the temperature (which, of course, is not something you can manipulate, but you'll get an idea of what CSI will do in the summer vs winter).

If you need help with any of that, just holler.

So you can leave your CH alone until you do your exchange in the spring, and just adjust your pH to keep your CSI where you want (close to zero).

 

[dailygenesis]

Have you dabbled with CSI yet? That's the number you want to keep an eye on. You can get away with an elevated CH by reducing some other factor to keep your CSI in check. Typically that is pH. Do you have the Pool Math app? Have you played with the calculators? There is one for CSI. You can enter your levels to get your CSI number. Ideally it should be 0 for a non-SWG pool, but anywhere between -0.3 and +0.3 is fine. If you play with the calculator, you can see what lowering you pH does to your CSI with a CH of 575. Give it a go. You'll also see a big difference when you play with the temperature (which, of course, is not something you can manipulate, but you'll get an idea of what CSI will do in the summer vs winter).

Thanks, I do have the pool math app (a paid subscriber even!). I noticed the CSI number last week. Hadn't looked into it closely and hadn't seen the calculator yet. Currently, my number is sitting at -0.24. You said -0.3 to +0.3 is fine, but the app gives a target range of -0.6 to +0.6.

Based on what I can see with the calculator, it looks like with these lower temperatures and my high CH level, I may need to push the pH a little higher to a keep the CSI in range. Maybe keeping pH closer to 7.8 or even 8.0. But are there any other impacts of maintaining pH that high?

 

[Dirk]

Thanks, I do have the pool math app (a paid subscriber even!). I noticed the CSI number last week. Hadn't looked into it closely and hadn't seen the calculator yet. Currently, my number is sitting at -0.24. You said -0.3 to +0.3 is fine, but the app gives a target range of -0.6 to +0.6.

Yah, that's me projecting. I strive to keep my numbers as close to perfect as possible, because I've convinced myself that the closer to perfect the longer my plaster will last. -0.6 to +0.6 is fine. -0.3 to +0.3 is better. Zero is best. Don't obsess about it, be reasonable, but if it's just as easy to get a better number, then why not?

Based on what I can see with the calculator, it looks like with these lower temperatures and my high CH level, I may need to push the pH a little higher to a keep the CSI in range. Maybe keeping pH closer to 7.8 or even 8.0. But are there any other impacts of maintaining pH that high?

No. It's the CSI that is more critical. I mean, you don't want to have your pH too far out of range. When you must push pH too high to get your CSI back in range, then you know it's time to lower the CH with an exchange. If you can maintain a CSI in range with a pH of 7.8 or less, you're golden until Spring.

It can take many months, even years, of these numbers being out of range to significantly impact your plaster. So you don't have to sweat your pH being "on the high side" for a few weeks, or a month or two. Try to keep pH in the sevens. If it pops up above that for a few days, don't sweat it. You just don't want your pool to live in the 8s, or have its CSI whacked out for months and months.

 

[Dirk]

I should also add that it is just as often poor pH that affects swimmers' skin and eyes, as it is too much chlorine. If you have "sensitive peeps," and your pH is way off, you might experience some discomfort after swimming (I would), so you can fool with the pH to see if you can make the water more comfortable. But most people will feel just fine with pH in the sevens. And, of course, in the winter when nobody is swimming, that's a non-issue.

I try to keep my pH at around 7.5-7.6 in the swim season, that's what feels right to me. I do what I need to to make sure my CSI can be OK with that. I need my CSI to be -0.3 (because that's what works best for my pool with a SWG (more on that later when you get there)), so with my pool at 85° (and my salt and TA where they need to be, 3000 and about 50-60, respectively), I need a CH of about 400. That gets me my -0.3 CSI (give or take). Those are my particular targets, just for comparison. Your pool would be slightly different, because you don't have an SWG yet.

 

[Dirk]

You also have to find a balance between the ideal water chemistry and what it takes to maintain it. To be spot on all the time would require monthly water exchanges and daily pH balancing and hourly FC testing and dosing, etc. It'd be a constant battle. So you find an equilibrium.

I need a CH of 400, but I'm not going to exchange water every month. Not even every year if I can help it. So I lower it to 350 and let it ride up to 450, then start over. So technically, my CH was 400 for about a day! Oh well. It averages out. I play with pH to compensate (to maintain my CSI most of the time), but don't obsess over it. If it's 7.5 some of the time, and 7.8 some of the time, oh well, close enough. You get the gist. Don't make yourself crazy, just do what you can reasonably do, without making the pool a full-time chore.

That said, my pool has a high demand for chlorine and acid, and I'm pretty lazy. Those things don't go well together! So what worked for me was automation. The SWG takes care of the FC level for all but about three months in the winter. And I installed an acid dosing system that takes care of my pH all year 'round. In fact, it balances my pH every hour during the day during swim season. I clean my filter once a year. I've gone about four years without an exchange because I only fill my pool with CH-free soft water (another form of automation).

So while I do obsess a bit about my levels, I use automation to deal with it! Just another example of finding what works best for you and your pool, both in terms of ideal chemistry and what it takes to achieve it.

 

[dailygenesis]

Thanks for all of the info. This makes sense.

So I lower it to 350 and let it ride up to 450, then start over.

I have been meaning to ask -- what makes calcium hardness go up? This sounds like it just naturally goes up over time. Why is that?

And I installed an acid dosing system that takes care of my pH all year 'round. In fact, it balances my pH every hour during the day during swim season.

This sounds amazing. How difficult are these to install? How expensive?

I only fill my pool with CH-free soft water (another form of automation).

How do you get this CH-free water? Are you using a filter on your hose or something different?

 

[PoolStored]

I have been meaning to ask -- what makes calcium hardness go up? This sounds like it just naturally goes up over time. Why is that?

Fill water with high CH.

How do you get this CH-free water? Are you using a filter on your hose or something different?

Water Softener.

 

[mgtfp]

You add calcium with fill water. Water evaporates, but calcium stays behind. You replace evaporated water with more calcium containing water and the cycle continues. Until CH level becomes to high.

 

[mgtfp]

You can make an experiment, or at least a virtual experiment in your head.

Dissolve a teaspoon of salt in one litre of water (I'm using salt instead if calcium, because you can detect it by tasting, the effect is the same). This is now your fill water. Try a little for reference, then keep it covered with a lid.

Fill a little shot glas with your fill water. This is your pool. The water in your pool has now the same salt content as your fill water and will taste identical.

Let half of the water in your shot glas pool evaporate and replace the lost amount with your fill water. Repeat this until all of your fill water has been used up to top up your pool.

You now have a shot glas with maybe 2cl of water that contains a teaspoon of salt. It will taste quite disgusting. If you have doubts, then try it...

 

[Dirk]

Thanks for all of the info. This makes sense.

I have been meaning to ask -- what makes calcium hardness go up? This sounds like it just naturally goes up over time. Why is that?


This sounds amazing. How difficult are these to install? How expensive?


How do you get this CH-free water? Are you using a filter on your hose or something different?

I think most of your questions got answered by others. But I'll fill in some details.

I replumbed my pool's auto-filler onto my home's interior water-softened plumbing circuit. I can test that water as CH zero, but my CH crept up over about four years anyway. I don't have a solid explanation for this. It's possible that even testing at zero CH, the water still has some CH anyway, and that built up. I suppose it's possible the CH leeched from the pool walls. I don't know if the physics of a pebble finish supports that hypothesis. The only other explanation is that while the water softener is regenerating every few days, it bypasses and allows the city's hard water through. If the auto-filler kicks on during that three-hour period, the pool is getting high-CH water, which will build up over time. But my city has very hard water and it took about four years before I needed to do a water exchange. Without the softener involved, I expect I'd have to exchange at least once a year.

Without a water softener, CH will enter your pool when you top off what evaporated. The CH never leaves, as it doesn't evaporate, so builds up over time. The harder the fill water is, the faster it'll build up.

I installed a Pentair IntellipH acid dosing system that handles all the acid injection. It was about $600. It works great. Installation was quite easy. I did have some trouble with a known defect of that unit after a while, but I fixed it and it won't happen again. But that unit requires the installation of its companion Pentair IntelliChlor SWG, so you can't just buy the InteillipH and install that stand-alone. There are other brands of automatic acid dispensers that are similarly priced, that can be installed stand-alone. Stenner is a good brand that makes acid dispensers. I've never installed one of those, but I expect it is not difficult. DIY if you're at all handy. Here's an example, though I'm not necessarily recommending this particular model, as I don't know this brand very well:

S1G45MFH1A1SUAA - 15 Gallon Chemical Tank With 45MPHP2 Fixed Pump - 100 PSI 3 GPD 1/4 Inch - Stenner

This Stenner S1G45MFH1A1SUAA is a 15 Gallon UV resistent chemical tank with a 45MPHP2 Stenner chemical Pump. This system is 100 PSI, 3 GPD, 120 Volt and includes 1/4 Inch Standard tubing. This combined chemical pump and tank system provides you a complete setup for your swimming pool..

www.poolweb.com

I have threads here that describe all of this in great detail (the softener hook up, the IntellipH installation, its problems and solutions, etc) if you're interested. I'm working on another that describes my CH build up and subsequent water exchange technique. I think I mentioned that already.