First TF100 Test Results - I will need some advice...

[peter.bastian]

Tested 2 samples:

City water: used to fill the pool when it runs low:
FC - 1.5
TC - 2.0 (CC was 0.5)
TA - 450
CH - 20
CYA - 0
PH - 8.2+

Pool water:
FC - 25 (!!)
TC - 25 (CC was zero)
TA - 300
CH - 300 (Lesson here - if you don't watch this one carefully, it'll go from blue to clear and you'll miss it)
CYA - 100+
PH - 7.8

The pool is a 12K gal IG pool with DE filter. Never gives me trouble. Crystal clear water, no cloudiness, no algae; I only add chlorine tabs to diffuser when it runs low. Thanks to this website, I have returned all "extra" chemicals to the pool store and now I have only two items in my storage bin - chlorine tabs (just bought a bucket - darn) and DE. Tabs go into a simple chlorine diffuser downstream of the filter with an adjustable dial to control dissolution of the tablets.

My guesses (which I want feedback on):
1) Drain the pool in 25% steps to lower CYA. This will also lower the FC to more appropriate levels. Refill pool and retest CYA and FC.
2) Add about 12 oz of muriatic acid to lower PH to about 7.5. And, it looks like I need to keep muriatic acid handy to deal with the high-PH city water when I add water to the pool.

Questions:
1) What are acceptable levels of FC? The OT test vial ranges from 0 to 5, so it 2.5 the target?
2) What do I do about the high TA of the city water? Does acid take care of this?
3) Anything else?

 

[JasonLion]

The correct FC level depends on your CYA level. The higher your CYA level the higher your FC level needs to be. See this chart in Pool School or my Pool Calculator for specific numbers.

The high TA and high PH of the fill water are going to be a bit of a challenge. It will take quite a bit of acid to get the TA level under control after each water replacement. The high TA level will cause the PH to rise rapidly, which you will need to keep an eye on for several days after each water replacement. You should read up on how to lower your TA level in this Pool School article.

You are already very close to calcium scaling. Any increase in PH, TA, or CH will probably cause some scaling. You need to keep the PH down for a while, which will tend to cause the TA level to fall over time.

 

[frustratedpoolmom]

Welcome to the forum I would just add to Jason's excellent advice... it sounds like you have been doing some reading, but I suggest reading the pool school articles again - refreshers are always good and honestly I think it took several reads for me to grasp everything , and at times I still have a brainf**t from time to time. Also, as for your FC "recommended Levels" - keep in mind that the vial for the CYA test goes to 100-your actual level could be higher. And you might have to lower more like 1/3....or do two partial refills to get the CYA into the recommended range.

The CH test can be tricky. Blue to clear? That doesn't sound right. Check this thread here
it discusses the CH test. Waterbear knows more about this test....

 

[Guest]

What kind of test kit are you using? Sounds like an inexpensive drop test kit. Blue to clear is usually the color change for TA in these inexpensive kits, not for CH, so I find that slightly suspect. First order of business, IMHO, is to bite the bullet and get a GOOD test kit.
category/pool-school/pool_test_kit_comparison

Also, the OTO test only tests TC so you cannot know your FC levels and your CC levels with only an OTO chlorine test. Therefore your .5pmm CC on your fill water is bogus if you used this kit for testing.

If you are using a good test kit such as the TF100 or a K2006 by Taylor then you seem to have some confusion in how to use. We can help you with that!

The first step to getting your pool in order is accurate test results. :-D

 

[peter.bastian]

Waterbear,

I was using a "fresh out of the box" TF-100 test kit. My question about the proper FC level relates to the daily testing using the drop test part of the kit. All my pool chemistry numbers came from the TF-100 suite of tests. Also, note that the 0.5 CC reading was for the city water supply. I just wanted to know what I was putting into the pool. I am confident that this is a correct reading.

Something was wrong with my first CH test - I repeated the test to get the results I reported in my post.

I am going to try to balance my CYA and chlorine levels this weekend by partially draining the pool, refilling, and adding acid to get the TA and PH down. Then, I will use aeration with a built-in fountain and monitor PH, and will retest everything later in the weekend.

 

[duraleigh]

It sounds like you are pretty much on the right track but you've got some unusual numbers, for sure.

I would not worry too much about the high FC but the CYA is too high so, you are correct, patrials drains and refills will fix both.

The problem you will then be faced with is the city water used for your refill will drive your pH and TA too high again. Acid is the answer to get your pH in line but the only way to permanantly lower your TA is thru the aeration process. You are going to have to do A LOT of aeration to get your tA down around 80 or so so your pool fountain may not be adequate. You'll also consume more acid as you aerate.

Some pools seem to do ok with high TA but with your fill water adding to your problem, I think you need to get it w-a-a-y down as it will creep back up all summer as you refill.

The tabs are why your FC and CYA are so high. Continued use of them will only put your CYA back to unacceptable levels. I would give that bucket of tabs you just got to someone you don't like very well and find and alternate method to chlorinate your pool. :-D

 

[Guest]

I would give that bucket of tabs you just got to someone you don't like very well and find and alternate method to chlorinate your pool. :-D

Or better yet, seal the bucket up tightly, store it in a cool, dry place, and use the tabs if you are going away on vacation or if your CYA drops too low (it can happen!) The sealed bucket of tabs can stay good for several years if kept DRY and cool.

 

[peter.bastian]

Guys,

Drained about 40% of the pool water and refilled with city supply. Added 1 gal of acid. Turned on the pool fountain. Here are the results after about 12-16 hours of aeration:

FC - 18
CC - 0.5 (will high FC eventually knock this down to zero?)
TC - 18.5
TA - 280
PH - 7.2
CH - 180 (I did the test the way waterbear recommends - made a huge difference in the test behavior and the results)
CYA - 100 (this is down from 100+, since the tube only measures to 100)

So, my CYA is still too high. Now that I understand the relationship between FC and CYA, and the fact that the source of CYA was my chlorine tabs, I also removed all the undissolved tabs from my chlorinator. I am switching to bleach. The previous owners used a pool service and never did this kind of testing on their own, so it's possible this has been a chronic, undiagnosed problem that I need to correct.

I see two options:
1) Instant gratification: I could repeat the process of draining the pool again, about 50% would be my guess.
2) Slow and steady: By switching to bleach, I would no longer be adding CYA involuntarily. Over the course of the spring/summer, with weekly backwashing, I would gradually lower the CYA to acceptable levels, but this would take a while.

What are you guys' thoughts on this? In retrospect, I probably should have drained the whole thing and started over.

Also, is there a possibility that any of this stuff (especially CYA) could be caught in my DE filter and I should backwash or do a more thorough disassemble/cleaning?

Finally, after reading all this stuff on this forum, is there any such thing as chlorine tabs that DONT have stabilizer? As problematic as this is/becomes, it would seem that there would be a market for stabilizer-free chlorine pucks.

 

[JasonLion]

Congratulations, you are making good progress.

Yes, high FC and direct sunlight will eventually bring the CC number down to zero. I wouldn't worry about it too much if it is only 0.5.

I would do another partial drain, but only perhaps 20% this time. Others will no doubt say different things. It is very important to get your CYA level below 100. It is very nice, but not critical, to get your CYA level down to 50. Once you get CYA below 100 you can let it drift down over the course of the season to a more reasonable level.

CYA will remain dissolved in the water. Once dissolved, it shouldn't be showing up in the filter. There is some possibility that you could have some calcium scaling in the filter, but unless the filter pressure is higher than usual I wouldn't worry about it.

There are some chlorine tabs made out of cal-hypo that don't contain any CYA. Unfortunately, they both contain CH and dissolve too quickly to be useful. Disinfecting chlorine only comes in a couple of forms, each of which has disadvantages. Trichlor, which is what the great majority of the tabs are made of, is the only one suitable for use in slow dissolving tabs, and it contains CYA.

 

[Guest]

So, my CYA is still too high.
I see two options:
1) Instant gratification: I could repeat the process of draining the pool again, about 50% would be my guess.
2) Slow and steady: By switching to bleach, I would no longer be adding CYA involuntarily. Over the course of the spring/summer, with weekly backwashing, I would gradually lower the CYA to acceptable levels, but this would take a while.

What are you guys' thoughts on this? In retrospect, I probably should have drained the whole thing and started over.
Definitely number 1! Keep up the "drain and refill dance" until the CYA is on target and then rebalance the water. IF you CYA levels were very high for very long it is possible that some has deposited on your pipes and pool. I have seen it happen that it starts to redissolve as people drain and refill and they think they are making no progress or even backtracking. Have patience and get the CYA down.

Also, is there a possibility that any of this stuff (especially CYA) could be caught in my DE filter and I should backwash or do a more thorough disassemble/cleaning?
No, won't really do any good. It is possible deposted throughout the pool and by continuing with the draining and refilling you will take care of it.

Finally, after reading all this stuff on this forum, is there any such thing as chlorine tabs that DONT have stabilizer? As problematic as this is/becomes, it would seem that there would be a market for stabilizer-free chlorine pucks.

Not one that can be used in an automatic feeder. Trichlor (the stuff they make pucks from) is a chemical made from chlorine and CYA that has the unique property of being very slow dissolving. Therefore it is ideal for use in erosion feeders. It's drawback is that for every 10 ppm FC you add with trichlor you are also adding 6 ppm CYA. The Chlorine gets consumed, the CYA does not and eventually builds up to too high levels in your water.

The next slowest dissolving form of chlorine, cal hypo, dissolves very fast compared to trichlor and cannot be used in ersion feeders like trichlor without danger of explosion. However, it is not made from CYA but it does cause calcium levels to rise over time.

BTW, the small amount of CC you are testing is from your fill water. Many localities sanitize drinking water with chloramines by adding ammonia in addition to chlorine.Shocking your pool and a day of full sunlight will take care of it easily once you get everything else squared away. It's the very least of your worries right now. Also, don't even worry about TA or CH until you get your CYA where you want it. If you have a filter that you backwash you might actually have a need for your CYA tabs. You might need to run a few in your chlorinator every so often to maintain your CYA level.
Also, don't know what kind of chlorinator you have but I am going to guess it's a Hayward because of your extremely high FC levels when you started. Haywards are notorious for being stuck either all the way open or all the way closed with no adjustments. It's the way they are designed. If this is the case I would recommend replacing it with a Pentair chlorinator.

It really would be most helpful if you could list your equipment in your signature.

My 2 cents!

 

[peter.bastian]

See my specs in the signature. Is there anything else I should include?

I am going to drain again. I will post water chemistry again once I have the CYA level. This time, I won't waste a gal of acid until I get the CYA in proper range (I am shooting for ~50).

 

[duraleigh]

The previous owners used a pool service and never did this kind of testing on their own, so it's possible this has been a chronic, undiagnosed problem that I need to correct

That would be my guess, too.

Just look what a big dent you've made in it already, tho.

One more drain and refill will probably put you in a ballpark CYA of 50-60 that you can certainly live with the rest of the summer.

Your grasp of the processes involved has been very quick.....nice work! :-D

 

[frustratedpoolmom]

Glad you are getting a handle on things and you figured out the tricky CH test....

BTW, I came to this forum because of problems associated with a clorinator/high CYA problem. When I joined my CYA was over 100 and after a series of partial drains I got it to 70ish, where it sat for 2007.
Spring '08 I got it to 50, and by the end of last summer it was down to the 20s. So I'm sure I'm looking to add some when I open next month. Ironic huh? I have a cartridge filter. Your level will likely drop quicker if you have a sand filter and backwash routinely, or live in a rainy area and get dilution or more splash out than I do. But yes, over time you will see it drop again, but right now I'd go ahead and get it down at least to the 70 range, then you can deal with it better. Save those tabs! They can be used if you go on vacation, or if you find you need to raise your CYA. Keep in mind that tabs can also lower your PH, so careful monitoring of PH and CYA when they are used is important...

 

[cubbybeave08]

http://www.waterwarehouse.com/Default.a ... e=19P6012A

I occasionally get catalogues from Doheny's Water Warehouse...A month or two ago I saw that they were selling unstabilized chlorine pucks...I was going to buy a bucket but it was for Commercial pools and only came in 100 lb buckets. It was like $250. When you use stablized pucks or sticks in a floater or something like that it rockets your CYA...I had an intex quick set pool and I used pucks...and tested with test sticks...My pool would always turn green...Turned out that I was raising my CYA so much that my pucks were not effective anymore. Get rid of them and just use bleach in the right concentrations, or if you don't trust that HTH makes a 10 percent liquid chlorine this is what I use...I use it in smaller concentrations, and it costs me about the same because I use less than someone who just uses regular bleach.

 

[peter.bastian]

OK - did second drain (further than 1st), and refilled. Here is where I am now:

CYA - ~70 (I am going to take a sample to a store that gives a numerical quantification of CYA in their water analysis to compare to my estimate). I am surprised it is not lower, but if this is correct, MAN, it's hard to get rid of this stuff.
TA - 360 (source water is alkaline, so acid will fix this)
PH - 8.0 (will add acid and aerate)
FC - 7.5 (Yeah! Down from 25!)
CC - 0.5 (source water is where this came from)
CH - 90 (this makes sense since the source water had a CH of 20 and I have diluted the pool water down significantly in last two days)

So, next steps:
1) Work on TA/PH with acid and aeration
2) Monitor FCs - I have bleach on standby
3) Should I elevate CH? I'll check pool school on how to do this.

 

[duraleigh]

Don't be shocked if pool store CYA tests disagree with yours....sometimes by a mile!! A lot of stores simply take a test strip, dip it in your sample, and then let a computer print you a "readout". Looks impressive but frequently worthless. You may also get a very accurate one. too.

The point is your own testing is what you should trust.....much more so than the pool store.

TA / pH - Remember that the only way to permanently lower TA is thru aeration. Your post seem to indicate that acid will do it.....not permanently. Acid will move pH (somewhat permanently) and TA (temporarily) but it's really the aerating process that allows you to permanently lower TA.

3 ways to raise your CH: (to around 250-300ppm, in your case)

1. Calcium Chloride is sold as a deicer. DowFlake is one brand.

2. Hardness or Calcium increaser from the pool store

3. Chlorinate with Calcium Hypochlorite

Listed in the order of my personal preference.....all will work.

Last, 70 is manageable for CYA...particulary in your warmer climate. If it were my pool I'd run it at 70 this summer and see how you like it.

 

[peter.bastian]

The pool store said my CYA was @ 34, which is much lower than the CYA test from the TF-100 test kit. I trust my own analysis much more, but I am not so confident about how to "read" that CYA test. It is rather subjective, and the test water is cloudy - so, what should I consider when reading the CYA tube until "the black dot is no longer visible"? I ask because there seems to be a range where you could say that you can't see the black dot.

I read about how to handle the high TA. I know that I need to knock down the TA/PH with acid and then raise the PH up again with aeration. My pool will be running it's fountain 24/7 while I monitor this.

Also, I bought some Calcium Chloride to get the CH up in the pool. The city water used to fill the pool has a CH of 20.

Thanks to everyone here, and to this forum and web site. :-D The best defense against pool maintenance problems and unnecessary chemicals is an educated pool owner!

 

[JasonLion]

To get a better idea of how to read the CYA test, try reading this article at Taylor and look at the pictures towards the bottom. The reading should be done in indirect sunlight and the dot should completely disappear.

One good way to get more experience with the test is to pour the liquid from the view tube back into the dispensing bottle and fill the view tube till the dot disappears again right away. You have a couple of minutes where the reading should be fairly stable. The most important thing is that you are able to get consistent results, each attempt should give fairly close to the same reading.

Also, as duraleigh said, don't be surprised if the pool store test result is way off. That is sadly quite common.

 

[duraleigh]

The best defense against pool maintenance problems and unnecessary chemicals is an educated pool owner!

Well said, my friend! BBB is not about magic, it's about education and testing. :lol: :lol:

 

[cubbybeave08]

Last, 70 is manageable for CYA...particulary in your warmer climate. If it were my pool I'd run it at 70 this summer and see how you like it.

Just to say that I would agree. Last year I had my pool CYA at 40, and still had to add lots of Chlorine...Not that I minded...but I would agree that at a higher level especially if pool is getting lots of direct sun light...This year I am going to take CYA up to about 60 and see where that gets me...Last summer...first summer with pool so I was just getting started with the BBB method, I just basically shot for the averages...This year i am going to see if I use a little less chlorine with a higher CYA...We didn't have a hot summer, but it was sunny all the time and I get about 8 -9 hours of direct sunlight through out June and July especially.