Testing Questions

Hi all
First of all let me say thanks for all the good information and dictation of mods and users here in the forum.
I have been lurking for the past few weeks learning all I can and am starting to feel more confident about the pool chem thing.
I still have a few questions but I will post my numbers first.

Free Ch 3 (DPD method)
Total CH 3 (OTO method)
TH 250-260
ALK 160-170
CYA 20-30
PH 7.6

I am not new to testing being a med tech for 12 years but I am new to pool testing. Let me say I am anal retentive about accuracy and precision in testing. I am using off the shelf test methods for now. I will have to wait until next year to convince my future wife to let me spring for one of Ben’s test kits she thinks I have spent enough of testing right now. I have one of the Wal-Mart 5 way test, Aquachem test strips, and DPD tablet method. The pool is 24’ above ground 52” walls so I compute around 13000 to 14000 gallons. I have a 2 hp pump and 22 in sand filter.

1. Just how accurate do I need to be? The CH color standards are not very good.
2. I have my oldest do a strip test before I let them get in during the day because I work nights and am snoozing. Are they good enough to use for them to get a guess before getting in the pool?
3. Is there a better method for CYA than the turbidity method?
4. Does oxygen shock (what can I say I got pool stored before I found this site) affect the CH test?
5. When is the best time of day for me to test?
6. Will the ALK slowly come down over time by adding acid to keep the PH down to 7.4 or do I need to go ahead and do the low PH and aeration procedure?
7. Will I ever get my life back and get less anal about the chem. in the pool? :cool:

I have a few more questions but I will post in the correct topics.
Thanks in advance
Steve

Quote:

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Originally Posted by medvampire

I have a 2 hp pump and 22 in sand filter.

1. Just how accurate do I need to be? The CH color standards are not very good.

Before you get too far, CH is commonly used as Calcium Harness in "pool talk", so to avoid confusion you should use Cl. The standards are easier to use against a white background.

2. I have my oldest do a strip test before I let them get in during the day because I work nights and am snoozing. Are they good enough to use for them to get a guess before getting in the pool?

I'd have to say that is probably a good use for the strips, as long as you know the chlorine isn't insanely high, which can bleach out the strips.

3. Is there a better method for CYA than the turbidity method?
4. Does oxygen shock (what can I say I got pool stored before I found this site) affect the CH test?

No

5. When is the best time of day for me to test?
6. Will the ALK slowly come down over time by adding acid to keep the PH down to 7.4 or do I need to go ahead and do the low PH and aeration procedure?

The alkalinity won't move much at 7.4 pH, but you are okay where you are with a vinyl liner.


7. Will I ever get my life back and get less anal about the chem. in the pool? :cool:

It takes me less than 2 minutes a day to test and dose my pool with bleach. A few extra minutes on Saturday to do the full-up tests. You will get a feel for it and it will become routine.

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Your pump is way oversized. You may have filtering issues and electric bill issues with that thing. You could get by with a 3/4 HP pump.

Sorry about the Ch vs Cl

Got "pool stored" on the pump and filter. My problem is that I work in rotation at a hospital for 7 days and have about 8 or so hours at home at that time. The kids talked me in to getting the pool but I enjoy it in my off time. I will test the cl and ph each day but I am nervious about adding chlorx when I cant be here to test the levels before the boys dive in.

Thanks
Steve

Steve,
If you add the bleach every night and then run the filter till morning the chlorine will be distrubuted throughout the water. As long as you aren't shocking the pool, i.e. dumping 4 jugs of chlorox in, it should be fine for them to go in the following morning. Just use the bleachcalc so you aren't dosing past target ppm.

** Also, I see from your sig that you use the Nature2... search for Nature 2 and read through the posts... you may have gotten 'pool stored' on that one too. Don't replace the cartridge next time.

Didnt plan to waste my $$$ on a nature 2 cartridge after reading here but I am gonna keep it in line for the trichlor tabs. I am put my bucks on one of bens kits

thanks
steve

Quote:

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Originally Posted by medvampire

Hi all
First of all let me say thanks for all the good information and dictation of mods and users here in the forum.
I have been lurking for the past few weeks learning all I can and am starting to feel more confident about the pool chem thing.
I still have a few questions but I will post my numbers first.

Free Ch 3 (DPD method)
Total CH 3 (OTO method)
TH 250-260
ALK 160-170
CYA 20-30
PH 7.6

I am not new to testing being a med tech for 12 years but I am new to pool testing. Let me say I am anal retentive about accuracy and precision in testing. I am using off the shelf test methods for now. I will have to wait until next year to convince my future wife to let me spring for one of Ben’s test kits she thinks I have spent enough of testing right now. I have one of the Wal-Mart 5 way test, Aquachem test strips, and DPD tablet method. The pool is 24’ above ground 52” walls so I compute around 13000 to 14000 gallons. I have a 2 hp pump and 22 in sand filter.

1. Just how accurate do I need to be? The CH color standards are not very good.
Since you said DPD tablets I assume you are using the LaMotte comparator. It is not the greatest. The Taylor DPD liquid reagent comparator is a better DPD test. The colors match up more closely. With a cya of under 30 your FC should be 1-3 ppm. when it gets to 30-50 3-6 ppm is where you should be.
2. I have my oldest do a strip test before I let them get in during the day because I work nights and am snoozing. Are they good enough to use for them to get a guess before getting in the pool?
for a quick check they are fine. Aquacheck (Hach) is one of the better strips as far as strips go. Under the Hach name they are used in the medical field for testing. I think you are being a bit anal about this:eek:...just let the kids enjoy the pool! Bumping your CYA and running the FC a bit higher is good insurance that the water is sanitized during the strong sunlight and not burning off. Keep tabs on the pH and keep it between 7.2and 7.6. chlorine is more effective at a lower pH then when it climbs up above about 7.8.
3. Is there a better method for CYA than the turbidity method?
IMHO, no. If you want to invest in a turbitity meter you can get more accurate results with the melamine precipitation test for CYA but it really isn't necesary to go to that expennse for the precision you need for your pool
4. Does oxygen shock (what can I say I got pool stored before I found this site) affect the CH test?
IF you mean does it affect DPD and OTO tests for chlorine yes it does. It will show up as combined chlorine and total chlorine on both reagents. Taylor has a reagent avaialable to use with their DPD tests to remove the interferance from MPS (potassium monopersulfate(oxygen shock, DuPont Oxone)IF you are using it you will always show combined chlorine even if there is none. Also MPS is only an oxidizer and NOT a sanitizer so don't use it in place of chlorine..alway make sure you have chlorine in the pool when you shock with it. IMHO, it is not the best choice for a chlorine pool.
5. When is the best time of day for me to test?
There is no best time as long as you test about the same time each day. that way variables like sunlight burning off chlorine are minimized.
6. Will the ALK slowly come down over time by adding acid to keep the PH down to 7.4 or do I need to go ahead and do the low PH and aeration procedure?
ALK is a measure of the carbonic acid/bicarbonate/carbonate buffer system in the water. the ALK test only measures the bicarbonate/carbonate part of it. By lowering the pH you shift the equalibrium to carbonic acid but have not actually lowered the amount of the buffer system (carbonic acid is just CO2 dissolved in water....think club soda). If you then aerate you drive the carbon dioxide out of the water (think shaking a bottle of club soda to make it go flat by driving out the CO2). As you do this the amount of the buffer system is decreased because the amount of carbonic acid goes down and the pH rises because the ratio of carbonic acid and cabonates/bicarbonate shifts back to the carbonates/bicarbonates but the equalibrium point is reached as the buffer stabilzes. Now there is less of this buffer system in the water which means you have lowered the ALK.
7. Will I ever get my life back and get less anal about the chem. in the pool? :cool:
I sure hope so, it doesn't sound like you are really enjoying your pool right now, It's not rocket science and there is a range of readings that are fine. Just get the water balanced, check your chlorine and pH an few times a week and ajust when necessary, and ENJOY YOUR POOL!!!!!;):D (and dump the Nature2. Why add copper sulfate and silver nitrate to the water? Chlorine is a much better sanitizer and also is effetive against viruses. Copper and silver are very slow acting bacteriastats and algaestats. Chlorine is much faster acting.

I have a few more questions but I will post in the correct topics.
Thanks in advance
Steve

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Hope this is helpful

WB YOU ARE THE BEST!!!
Thanks for the answers here and in the cl forum. I guess I worry about the kiddies way too much. The boys are 13 and 10 and I cant be there for them a week at a time due to work and just dont want them hurt due to my absence. I see way too much in the er here and almoste didnt let them have it. I have worked with the Hitachi chem ua strips and liked them very much. Good accuricy and precision.
I have a color spectrophotometer and turbitity meter here at work may just for fun set up some standards and test here.(need to get a life hunh?)

Thanks again for helping a worried step father. (gonna adopt soon I hope their bilogical dad is a real piece of crap)
Steve
I get to enjoy the pool tommorrow, out of rotation in the morning!!! A few days stress free swimming with the girl friend and the boys.

Quote:

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Originally Posted by medvampire

Hi all
First of all let me say thanks for all the good information and dictation of mods and users here in the forum.
I have been lurking for the past few weeks learning all I can and am starting to feel more confident about the pool chem thing.
I still have a few questions but I will post my numbers first.

Free Ch 3 (DPD method)
Total CH 3 (OTO method)
TH 250-260
ALK 160-170
CYA 20-30
PH 7.6

I am not new to testing being a med tech for 12 years but I am new to pool testing. Let me say I am anal retentive about accuracy and precision in testing. I am using off the shelf test methods for now. I will have to wait until next year to convince my future wife to let me spring for one of Ben’s test kits she thinks I have spent enough of testing right now. I have one of the Wal-Mart 5 way test, Aquachem test strips, and DPD tablet method. The pool is 24’ above ground 52” walls so I compute around 13000 to 14000 gallons. I have a 2 hp pump and 22 in sand filter.

1. Just how accurate do I need to be? The CH color standards are not very good.

Accurate enough so your pool stays sanitary. I'm not being glib. Your FC (free chlorine) level depends on your CYA level--see the Best Guess table. Your CC level (combined chloramines) should be 0. TC (total Chlorine) = FC + TC.

2. I have my oldest do a strip test before I let them get in during the day because I work nights and am snoozing. Are they good enough to use for them to get a guess before getting in the pool?

I think they are FINE for that. If the chlorine tab is white, it either has little or no chlorine or has bleached out the tab. In either case, they shouldn't go it the water. Be VERY careful the oldest understands how to run the test correctly. The LaMotte strip is a 2 second dip and instant read. The AquaChek is a 2 second dip, and a 15 second wait to read. Ignore the other tests on the strips. They are very difficult to read correctly, if at all.

3. Is there a better method for CYA than the turbidity method?

Probably. But why bother?

4. Does oxygen shock (what can I say I got pool stored before I found this site) affect the CH test?

As I'm an advocate TOTALLY of bleach for chlorination, I would never use an oxygen shock. I presume you aren't using a bacquacil pool.

5. When is the best time of day for me to test?

I'll go against the mainstream: late in the day or early evening. That way, if you need to add chlorine, the UV from the sun won't break it down. There's no point to testing if you aren't going to act (add chlorine, adjust pH, etc) after the test. Saying that, I generally test in the morning because that's when I have time. Testing ANYTIME is better than not testing.

6. Will the ALK slowly come down over time by adding acid to keep the PH down to 7.4 or do I need to go ahead and do the low PH and aeration procedure?

You have a vinyl pool. Alk levels up to 180ppm are PERFECTLY fine in vinyl and shouldn't be messed with. You can even go as high as 200 without having to take action. But the Alkalinity forum has directions on lowering alk.

7. Will I ever get my life back and get less anal about the chem. in the pool? :cool:

Check my sig line!

I have a few more questions but I will post in the correct topics.
Thanks in advance
Steve

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I agree your pump sounds WAY too big for your filter and pool. It burns electric and makes your life harder to keep your water clear.

Ben's kit, or its equivalents--the Taylor 2006 and Chlorine FAS-DPD Service Kit from Leslie's--will pay for themselves in the first year alone. They will continue to pay for themselves year after year after year. IMHO, not to have a kit at this level is penny-wise and pound-foolish. I bought my PS-232 when I had a 3,700 gallon 15' round Intex Donut and was SHOCKED by what I learned from it--and the problems it solved and prevented. Even then it was worth every penny.