First Test Results

[Ray Mondo]

Hi All,

My new test kit arrived from Palintest Australia this morning. Now that I can perform the required tests I have promoted myself from the Just Getting Started forum to this one.

Results this morning's tests, with the new kit, are:

pH- 7.6 (evaporation had dropped the water level quite a bit until good rain yesterday topped it up)
FC- 1.0
TC- 1.5
CC- 0.5
TA- 80
CH- 150
CYA- 50

Apparently the Palintest SP315C kit has been superseded, at least in Australia by the SP319/ML kit.
It uses (mostly) test tablets and is easy to use.

Before I start trying to get my head around the pool calculator I would appreciate advice on these measurements, just to get me started on the right track. I haven't made any adjustments, but normally need to add about 250ml of Hydrochloric acid most days to keep the pH down.

Many thanks for the advice received so far, without which I would not even have got to this stage.

 

[frustratedpoolmom]

First things first, is your chlorine level - refer to the CYA chart to determine what your appropriate chlorine levels should be. If your CC climbs any higher you'll need to shock the pool. Then use the Pool Calculator to determine how much chlorine to add. You will put a FC of 1 in the "now" column and then your target or goal and then it calculate, and it will tell you how much bleach/chlorine to add. Hope that makes sense.

Then, when you are ready to tackle it, your CH is on the low side, but that's not as critical as the chlorine issue right now.

Test the PH daily and lower it with acid as usual, if it rises above 7.8.

Hope this helps.

 

[duraleigh]

Hey, Ray,

Echoing what FPM has said, get your chlorine up around 3-5ppm and keep it there. Check out the chlorine/CYA chart in Pool School.

Why did you comment about evaporation related to pH?

Get your chlorine where it needs to be then follow the rest of what FPM said.

How does your water look?

 

[Ray Mondo]

Echoing what FPM has said, get your chlorine up around 3-5ppm and keep it there. Check out the chlorine/CYA chart in Pool School.

OK. That's interesting. The test kit I have been using until now shows the 'ideal' free chlorine level as being 1.0 to 1.5ppm. However the latest pack of pool-shop sanitizer I bought recommends 3.0ppm at the current temperature of 27 Celsius. So, I'll get it up by adding some directly, and will increase the chlorinator output to maintain it at the higher level.

Why did you comment about evaporation related to pH?

Only to make the point that the recent rain probably hadn't diluted any chemicals as it was just replacing what had evaporated over the past couple of weeks. There was not enough to overflow. Because Brisbane is short of water, we try to keep the pool topped up with rainwater off the roof.
How does your water look?

How does your water look?

The water in the pool is crystal clear. Once I get the chemistry right I need to investigate some dark patches that have been spreading around the sides. I had the impression that I was keeping them under control by keeping the pH low, but this summer they seem to be spreading regardless.

Thanks guys for the helpful response (and quick!)

Cheers,

 

[chem geek]

Do not go by the recommended FC levels in the test kit nor what the pool sanitizer recommends since neither account for the CYA level. The active chlorine level that determines sanitation and oxidation rates is related to the FC/CYA ratio, not to the FC level alone. Instead, go by the Chlorine/CYA Chart which will provide plenty of sanitation and prevent algae growth without the need for any supplemental algaecide, phosphate remover, or any other products.

 

[polyvue]

The water in the pool is crystal clear. Once I get the chemistry right I need to investigate some dark patches that have been spreading around the sides. I had the impression that I was keeping them under control by keeping the pH low, but this summer they seem to be spreading regardless.

Hello Ray --

Have you determined what those dark patches are? If the patches are g r o w i n g instead of depositing... well, you may already have the answer. Don't want to let a bit of algae spoil your summer by taking you away from swim time and the pleasures of pool maintenance, right? If it's algae, upping the chlorine level quickly will do you a world of good and there are straightforward remedies for metal and other types of stains, too. I can't give you any better advice than you've already got so would just point you toward two articles that discuss defeating algea and diagnosing stains. Lots of other stuff in Pool School you might be interested in, and there's no need to bring an apple with you to class!

 

[Ray Mondo]

Yesterday I added 500g of pool shop sanitizer AND increased chlorinator production from 15 to 25 (on a scale of 30).

Ooops! Too far. Now FC and TC are both off the scale at 5+
pH is still at 7.6

I'll see where chlorine settles after a couple of days of chlorinator only.

Today is a bit cooler, cloudy, with rain forecast.

Any comments/feedback appreciated.

Thanks polyvue: I'll read the stuff on defeating algae and diagnosing stains. At this time of year in Brisbane I'm not letting a few stains/deposits keep me out of the pool.

Cheers,

 

[PaulR]

Just curious, what's the active ingredient in the "pool shop sanitizer"?
--paulr

 

[Ray Mondo]

Just curious, what's the active ingredient in the "pool shop sanitizer"?
--paulr

The label says "Active Constituent 630g/kg available chlorine Cl) present as trichloroisocyanuric acid. Also contains 300g/kg sodium tetraborate pentahydrate".
Sounds like a good argument in favour of buying the base ingredients and mixing your own cocktails.

BTW, I have been comparing sodium bicarbonate prices. So far the cheapest I can find in a supermarket is about 5 cents per 100g cheaper than the cheapest in a pool shop. So I bought 4Kg to be going on with.

 

[PoolGuyNJ]

Start using bleach. Trichlor and dichlor add stabilzer you don;t need,

Scott

 

[PaulR]

Yes, your CYA is fine where it is, you don't need trichlor boosting it up.

Around here, liquid bleach (sometimes sold double-strength by pool stores as "liquid chlorine") is frequently the cheapest source of chlorine, per PPM. Look for "sodium hypochlorite" on the label; name-brand bleach typically runs 5%-6%, pool store liquid chlorine 10%-12.5%. One liter of 6% bleach per 10,000 liters of pool water will increase FC by 6 (with the obvious change for any other percentage), so it's often easy to figure amounts in your head as well.
--paulr

 

[Ray Mondo]

Thanks guys,

I think I'm getting the hang of this. I'll check out the supermarket bleach.

I did the full test again today and the chlorine is still way up. I've turned the chlorine production down to zero and will test it daily until it gets down to about 4 and will then start 'tweaking' the production rate to maintain that level.

Today's test results were:

Temp: 26C
pH 7.6
FC 5+ (off the scale)
TC 5+ (off the scale)
TA 50
CH 200
CYA 50

My Palintest kit also has a calculation for 'balance'. It comes out at 11 which it says is ideal.

Thanks again for the advice. This is the way to go, for sure!

 

[PoolGuyNJ]

Try diluting the pool water with an equal amount of distilled water. If your pool sample size is 2 cc, add 2 cc of distilled water and retest. Repeat as needed till you get a reading you trust and multiply by the number of dilutions.

Scott

 

[waste]

JT, congrats on the kit!

As Scott said, the dilution (A/K/A - shotglass method) can help you determine ~ where your cl level is (you can use multiple dilutions, i.e. 2:1, 3:1 BUT, you loose a little more accuracy with each higher dilution )

I'm not sure if the others noticed that you're using a SWCG. With a SWCG, you want at least 50 ppm cya, which is where you are, and the fc minimum comes down some (IF memory serves, the minimum target goes from 7% to 4.5% - I'm pretty sure the info is in Pool School)

One other thing 'stands out' to me - your CH went from 150 to 200 and the alk dropped from 80 to 50 (I'm not sure that the 250ml of acid you add, almost daily would do that- I can see it happening, but I'm not one of the chem gurus ) While you can easily use some of the 4kg baking soda you bought to bring the alk back up (use Jason's calc to figure out how much to add to get to ~70) I'm wondering how the CH raised 50 in a couple of days - you added tri-chlor not cal-hypo.

Have fun with the pool and the kit! I'm just trying to point out a couple things I noticed, in hopes that the more chemically knowledgeable folks will chime in

Let us know how the stains are coming along/ what you find.

 

[Ray Mondo]

As I may have mentioned previously, Brisbane has a water supply problem so we are reluctant to top-up the pool with tap water. Our solution has been to divert one of the down-pipes from the roof, into the pool. Due to the lack of rain he level has been dropping steadily due to evaporation. We were out of town last weekend and, because rain was forecast, meant to remove the down-pipe diversion. I forgot... and it rained, big-time! When we returned on Sunday night the pool was full and overflowing so I thought my chemistry would be destroyed. But it wasn't too bad (I think).

Temp = 27C
FC = 3
pH = 7.8
TC = 3
CC = 0
TA = 50
CH = 150
CYA = 40

I'm finding it difficult to get a very precise reading on FC and TC using the comparison scales on either of my pool test kits, but this is the best I can get it. I must have become too accustomed to digital readouts. I'll continue to monitor the FC and TC daily as much as possible. Hopefully that will helps smooth out the effect of any mis-readings.

Anyway, I thought I would now move on to the main problem I am having, which is this nasty, steadily growing stain. It is mostly round the sides of the pool with very little on the bottom. The very worst spot is directly opposite the main inlet of water from the SWCG. It has been accumulating for a few years and advice from my local pool shops has not helped. I have the impression that, when it first started appearing that it was due to high pH. If I lowered the pH it seemed to disappear. Other than those observations I thought the best way to 'describe' it would be to post a photo (below). I will get some ascorbic acid over the next couple of days and test with that.

Please let me know if I should be posting this to a different forum.[attachment=0:bdah6ivv]Pool-Stains 9 Feb 2010 .JPG[/attachment:bdah6ivv]

Pretty nasty eh?

Cheers,

 

[dmanb2b]

Hey Ray, welcome to TFP

Anyways, if you don;t mind me asking, how are you getting those FC/TC readings? Is it the OTO Chlorine test that turns the water yellow? It is interesting that your water seems clear, but you seem to have organic growth on your pool walls. I'm almost incline to say you need to shock your pool, but I'll let the experts chime in.

PS in case it hasn;t been mentioned above, I would strongly suggest your read the articles in pool school a few times over, after which the advice you get will certainly "click"

Cheers!

 

[PoolGuyNJ]

With TC @3 and FC @0, Its likely algae. TC is total chlorine and FC is free chlorine. Free chlorine does the work. With FC @0, there is nothing to kill the algae. Bring the FC to 30. That will kill whatever is in the pool and get your TC and FC to be nearly equal, as they should be. Wait 24 hours or so for the algae to loosen it's grip and vac to waste. Then refill and balance. Try to keep the pH down below 7.6 to prevent scale, allow the choline to be more effective, and is easier on the eyes.

Scott

 

[frustratedpoolmom]

First, confirm it's organic (I too suspect it is) by holding a trichlor tablet on the staining to see if it fades. If its organic the spot should bleach out. Once you confirm it's organic, refer to the CYA/Chlorine chart for your "shock" level of chlorine (16 - 30 is a bit overkill IMHO) and then follow the instructions for "How to Shock Your Pool" in Pool School, also read "Defeating Algae". If you follow those steps, and then maintain proper Free Chlorine levels at all times using the CYA chart as your guidance, the suspected organic staining should fade away and never return. Brushing these areas (along with the entire pool surface) while the FC is at shock level is also a good idea.

If a trichlor tablet, held in place for a few minutes, does nothing to the staining, report back.

Edit: A vitamin C tablet held in place will cause the stain to vanish too, if it's metal staining (which tends to worsen when PH creeps up, as you said you were told before.) But to me, that looks organic.

Acid will bring your PH down, but your TA is getting a bit low. So get the PH down to 7.5 and then use Baking Soda to bring the TA to at least 60-70. If the TA gets too low it can cause the PH to have unstable swings in either direction...

Again, once things have stabilized in the chlorine/PH department we can work on your CH level.

 

[Butterfly]

Hi Ray,

Yep, I agree that you need to shock your pool.

With your CYA of 40, your shock level is around 15 or 16 FC. See CYA/Chlorine chart in my sig and in Pool School.

Here are the instructions on how to shock your pool from Pool School.

fpm....was typing at the same time..... :lol:

 

[frustratedpoolmom]

fpm....was typing at the same time..... :lol:

GMTA