Test Results - need analysis please

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MaxAcceleration

MaxAcceleration

LifeTime Supporter
Aug 29, 2012
33
Caledonia, IL
Pool Size
24000
Surface
Vinyl
Chlorine
Liquid Chlorine
Here are my results per Taylor K-2006C

FC = 3.5
CC = 1
Ph = 7.0
Base Demand Test= 7.5
Alk = 170
Calcium= 170
CYA= 120

My water is clear but I have a few questions:

1. I plugged all this into the pool calculator and it said to add 285 by weight of Borax. It said to do nothing about the high alkalinity. I was always under the impression that you should adjust for alkalinity first before messing with PH?

2. I use Trichlor pucks in two floaters. I also added 20lb of Bioguard Optimizer Plus (before I knew any better). Is the recommendation to switch to a pure liquid chlorine instead of pucks (or at least a mix) so my CYA doesn't get high? It just seems it would be a pain to lug home all the liquid chlorine each week, plus its shelf life is not long.

3. Does the calculator ever tell you to shock the pool? Or is it assuming that maintaining a proper chlorine level will not require shocking? I never asked for my Combined Chlorine level so how would it know if it's not time to free some of that CC up?

Thanks a lot,
Jamie
 
It is not that hard to bring home the bleach. My CYA is 40 so my bleach needs are only 5 to 6 cups a day! I get my chlorine from the ACE hardware store up the road. It is 11% chlorine so I do not have to carry as much as someone that gets theirs from Walmart.

We get 10 gals of 11% chlorine at a time. It lasts us about 3.5 weeks. Rain/storms/sun do change our needs but with the test kit it is SO easy to adjust what we need.

We spend $4 to $6 a WEEK on our pool! :party:

THANKS BBB and TFP!!

Kim
 
I'm sure there are more knowledgeable people than me that'll chime in, but the first thing I'd do is add some bleach/liquid chlorine according to the Pool Calculator to bring your chlorine levels up and immediately stop using the pucks as your CYA level at 120 is far too high... it should be between 30 and 50 and right now your shock level is literally off the chart. You should probably do a partial drain on your pool to at least get the CYA down to a more reasonable level (note: I'm unfamiliar with partial drains on a vinyl pool, so please read up on that before you do it).

With your FC at 3.5, you're not providing enough sanitization because of your high CYA. You should have a minimum of 6 for your FC, but with the CC of 1, I'd probably shoot for a higher number while you fix the CYA. As for your CC, that should never be higher than .5, which means you're going to have to begin the shock process when you get the CYA level under control. With a CC of 1, something is in your water and your current chlorine level is inviting trouble.

As for pH, yes, that will need to come up as well and your alkalinity is too high. Since on the K2006C the pH scale's lower limit is 7, your pH might actually be lower than that. Might want to consider re-doing your base demand test to see what it takes to bring it up to 7.2, then aerate the pool to bring the pH up higher (of course, if you do a partial drain and your fill water is higher in pH, it'll bring it up that way). Then to get your TA under control, when your pH is around 7.7-7.8, you would use muriatic acid to drop the TA and repeat the cycle. See this link: pool-school/lowering%20total%20alkalinity

If you regularly maintain your levels and have clear water and CC of less than .5, you shouldn't have to shock.

Definitely spend some time reading up on things in Pool School: pool-school/
 
Rtkane's post is spot on. The only thing I would add is if your closing your pool soon, you might want to just get by without the partial drain meantime. Definately stop using the tri-Chlor until such time that you need to increase CYA, which I presume will be next year sometime.

Regards
Stuart
 
Unless you are running a saltwater system, your CYA should be between 30 and 50 ppm. Carefully change out water until your CYA is in this range, stop using stabilized chlorine sources such as trichlor and dichlor and switch to bleach, retest your water after your water change-out and post results here. We will then recommend a course of action from that point.
 
That actually answers quite a lot for me, thanks for the replies.

I didn't fully understand the strong relationship between CYA and Chlorine. That would explain why I was getting some algae this year even though my chlorine "looked" ok on the test strips (before I bought the k2006c).

Yep, I'm getting close to the end of the season and will take out a significant amount of water when I close (below the return lines) so that should help. I will stick with Chlorine for now on and hopefully the combination of lowering the water and backwashing next year I can get the CYA under control.

I have a couple more follow up questions to add:

4. With my CC at 1 and my CYA extremely high you said to add a significant amount of chlorine, why does the pool calculator only say to add 135oz of 15% bleach. If I remember right that's less the "normal" amount per week it says to add on the back of the pool chlorine bottle.

5. Do you buy chlorine at the pool store since it's more concentrated? Or just Clorox from Walmart? I would think the pool store highly concentrated would be the better deal, just want to make sure.

6. Per the pool calculator I bought Borax tonight to raise my PH (which I haven't added yet). If Aerating does the same thing (raise PH) why did the calculator say to add 18 pounds of Borax? Can I just aerate? Or would that take too long for that amount of a change?

7. You said "If you regularly maintain your levels and have clear water and CC of less than .5, you shouldn't have to shock." Isn't the chlorine going to eventually get CC'd just from normal dirt/bather load? Even according to the Taylor test kit it says to add 10x the normal amount of chlorine in order to shock and free the CC up. (don't have it in front of me so I hope I didn't misquote that).

Thanks Much,
Jamie
 
Your best bet is shop around some. At times the pool store are a better deal, but not often. If you post prices we can help you out. Ya it maybe more concentrated, but the prices are marked up a lot.
 
4. The pool calculator will only give you the amount of bleach you need to put in to bring your levels up from the "Now" column to the "Target" column. For your CYA level, your target FC range is 6-11. The 135oz is taking it from 3.5 to 10 (using 15% like you said). With retesting every day, you'll find that you have to add more bleach each day to maintain that FC of 10 because of it being used up by the organics in your pool, which will end up being more than what the bottle instructions call for.

5. You can buy chlorine wherever you'd like--I bought the large bottles of regular bleach at my local Lowes, but bleach (unscented / original) from WalMart would work equally as well (I've since switched to a SWG). Higher concentrations from the pool store may be a better deal (it wasn't for me locally in NJ) and may be more convenient to carry since it's not nearly as many bottles as lower concentrations require.

6. The pool calculator isn't taking into consideration that you want to drop your TA at the same time. It gives instructions for each individual item on how to adjust that particular item. The folks here on the boards and Pool School are the ones that can do the analysis and give you the proper steps when you're trying to impact multiple things (like bringing up the pH and dropping the TA!). You can aerate to bring pH up, but it's a longer process and since we're not entirely sure if you're at a 7.0 or less, you should get the pH up to within a reasonable range and then start to aerate.

Since the K2006C only shows pH down to 7.0 and you may actually be below 7.0, use your base demand test and per the instructions add one drop at a time and mix after each until you get the pH up to 7.2. Then refer to Table D in the book in your kit shows to see how much soda ash to use based on the number of drops the base demand kit requires. I'd take that amount, convert it to ounces and plug it into the "effects of adding chemicals" section of the pool calculator under "washing soda or soda ash" to see what the increase in pH is. You can then change the selection in that area to "borax" and play with the amount until you get an equivalent change in pH (try doubling the soda ash amount). Once you get it in range, switch to aeration to bring the level up higher than that. It's just hard to know whether your pH is a 7.0 or a 6.7 and important to get back into range pretty quickly.

7. Here's a thread that talks about what you're asking: please-clarify-question-about-shock-combined-chlorine-t6727.html

Overall, I've learned to trust the people on this board as well as Pool School and would rely on them before outside instructions. Definitely read through the shock process in Pool School. You can do the shock process with high CYA levels, you just have to add a phenomenal amount of chlorine. For CYA of 120, you're probably going to have to get your FC level up to 47 or 48 minimum and maintain it until the water is clear, the CC is .5 or less and you've passed an OCLT. That's an initial dose of nearly 2300 ounces of bleach (6%) and a lot of bleach to maintain that level, which is why its recommended to get the CYA level down first, but if you're not going to worry about the CYA until you refill, that you keep the FC at the upper end of the recommended range for 120 CYA.
 
Thanks a lot for that great feedback!!

I called Walmart and my pool store and here are the calculations I did:

Walmart: 10% $6.47 for 2 gallons 10/100*2*128/10= 2.56 ounces chlorine/dollar
Pool Company: 12% $2.79 for 1 gallon 12/100*1*128/10= 1.53 ounces chlorine/dollar

So it looks like I get more Chlorine ounces per dollar at Walmart.

One additional question:

8. I will get my CYA under control after I drain for the winter. But for now, since I have to maintain a high chlorine level of 6-15 (per the pool calculator) as a result of my high CYA, is that safe to swim in? I thought anything above 5ppm is not good?

Thanks again!
Jamie
 

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MaxAcceleration said:
Thanks a lot for that great feedback!!

I called Walmart and my pool store and here are the calculations I did:

Walmart: 10% $6.47 for 2 gallons 10/100*2*128/10= 2.56 ounces chlorine/dollar
Pool Company: 12% $2.79 for 1 gallon 12/100*1*128/10= 1.53 ounces chlorine/dollar

So it looks like I get more Chlorine ounces per dollar at Walmart.
Click to expand...

Here is the correct formula for calculating the cost per chlorine ounce, minus the water that's in it. This tells you how much of a concentration free available chlorine you get per bottle(s) for your moneys worth.

Ounces you purchase, times the percentage of CL in decimal form, then divide the amount you pay by that number.
Like this
Walmart: 256*0.10=25.6
6.47/25.6= 0.2527 or 25cents/CL Oz.
Pool Company: 128*0.12=15.36
2.79/15.36= 0.1816 or 18cents/CL Oz

The pool store is actually much cheaper.
I wish I could get it that cheap here. :cry:
 
Safe to swim in under your shock level, So FC anywhere between 5 and 27.9 is fine to swim in with CYA at 120. Just looking at the raw prices suggests $5.58 for 2 gallons from pool store or $6.47 for 2 gallons from Walmart, therefore your pool store price is both cheaper and returning more chlorine per gallon.

Regards
Stuart
 
Thank you for the correction to the calculation of cost per chlorine! I will use that for now on.

I brought the PH up using Borax and hit a perfect 7.5. The pool sparkled like it never has before! It is looking very clear at the moment, too bad it still has the high 120 CYA! Which I retested today just to make sure I tested it correctly and it's still about a 1/4 inch below the 100 mark on the Taylor test kit when the black dot disappears.

To get my Alk level down I've begun the acid/aeration process (lowering to 7.2 then aerating back up, then repeat) and will see how that goes.

I also added the correct amount of chlorine tonight to bring the pool up to 12ppm. I will retest the CC tomorrow and shock to 39ppm if needed.

I have two additional questions (you guys are great btw!):

9. So I'm getting away from the floaters considering my CYA was 120! What is the process for using chlorine, daily, weekly, only when we swim? With the floaters it would slowly add all week and if we didn't swim for a few days no big deal I knew I was putting chlorine in the pool and would just top it off each week.

10. Since I'll be doing a partial water refill to get rid of CYA, any recommendations on using well water vs water softener water? My well water is very high in iron and will produce orange nasty rotten egg smelling water. I have an "iron genie" and water softener that makes the water clear and fresh. I also have a control valve I can switch to either draw straight from the well or via the conditioned water. The problem is it turns the water a funky color and probably adds a lot of metals to the water. In the past I was adding "scale and stain control" to combat it. I also have limited amount of conditioned water to use since the tanks can only hold and process so much at a time. I guess the question is should I use conditioned water or nasty well water or maybe a combination (50/50) of both?

Thanks again,
Jamie
 
You just add chlorine as you need to to keep the FC within a certain range. Typically, this means adding bleach every couple of days or so.

Water without metals is always better than with metals. It's unlikely that a household water softener could keep up with the demand of a pool fill, but if you are topping off a bit here and there, it might work. If you do use well water though, you can always use a sequestrant to keep the metals in solution rather than them being deposited on the walls of your pool.
 
I add my chlorine once a day (in the evening after dinner). I test every other day. I did it once a day for the first two weeks so I could get a feel for what my pool will do under daily changes-sun, clouds, swimmer, etc.

Water refill-I can't help you there. I THINK (and we all know how that goes!) that if you pulled your water down just a little then refilled using your soft water that might work to keep the yucky well water out. Is there any way you could truck in water?

I am VERY lucky in that my well water is WONDERFUL! I would rather drink my well water than any other bought water :party: !

Good luck!

Kim :cat:
 
I vote for the softened water (have a bad well and have been fighting iron stains and using boatloads of sequestrate) although believe you will only get about 1400 gallons per fill before you have to regenerate, so it would e slow going unless you have dual tanks. You could help the situation a bit by putting a filter on your fill hose.

I live in Michigan with similar climate. Here, I am told that many pools lose their cya over the winter due to a type of soil bacteria that can affect melt/runoff and that converts the cya to ammonia. Assuming you've had your pool for more than one season, can you ever recall that happening to you -- 0 cya on opening?

If that HAS ever happened to you, you might want to wait until spring and see between the draw down and possible bacteria what your cya read is on opening. Then, if it's still higher than 50 ppm, consider trucking in a half-load of water, and because you're vinyl, adding/draining at same time to keep water in for the liner-- if the pool doesn't drain as fast as the water from the truck, you could use a trash pump to speed up.

I had zero cya on opening, but mine was a foreclosure swamp and may have been left wide open for a year before re agent thought to put the cover back on. Iknoe that the owners BEFORE the foreclosed owners used pucks with an inline feeder, so I'm certain there was a LOT of cya at one point ;)
 
My results have been much better, I'm now at:

FC = 11
CC = .2
Ph = 7.5
Alk = 175
Calcium= 170
CYA= 120

I eventually have to work on a partial refill for the CYA to lower, but I'll live with it until the end of the season when I have to partial drain anyway.

One big question I have is I read the pool school advise on lowering alkalinity and it said not to worry about it unless I have high calcium or if I want to slow down a rising PH. I don't have either of those but I thought you always wanted to lower the alkalinity so you don't get PH bounce (inaccurate PH results)? No?

Thanks,
Jamie
 
Low Alkalinity = pH Bounce
Alkalinity Within Limits = pH Buffering
High Alkalinity = pH Lock

Since you have reached 7.5pH with TA of 175, I don't think you need to worry about it really, it's only a problem when TA is high and your pH is Locked outside normal range (usually higher)

EDIT: The only other problem you need to watch out for with high TA is a high Langelier/CSI Index.

Regards
Stuart
 
What was not mentioned in this whole thread is that the cya might be much higher than 120 because the test can only read to about a 100. What I would do is test it again using 50% tap water and 50% pool water and double the results, if I was a betting man I would say it is around 150 or so.....Mike
 

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