First opening. Test results within. Green water.

[poollover2012]

Hello Everyone,

I recently moved into a place with a salt water pool and I'm undergoing my first opening. I have never owned a pool before. We removed the cover and found that the water was very dark and dirty. I had some help from a pool installer so far, who showed me how to operate everything and explained some of the basics of maintenance. He decided to shock the water and after a few days, it's now an emerald green in colour. He added 1 bag (20kg) of salt to bring the salt content back up to about 3000ppm. The reading on my aqua rite display indicated 2700ppm. It's been 4 days since we first shocked the water. I also took a sample of water to a local pool supply shop that does free testing and here are the results:

Pool size 38 x 18, 25748 US gallons, vinyl, in-ground
Stabilizer 10
Total Alkalinity 125
ph 7.8
Calcium Hardness 200
Total dissolved solids 2500
Free Chlorine 5.0 ( 1 Hour after last shock treatment)
Combined Chlorine 0.0
Bromine 0.0
Dissolved metals None

I bought some stabilizer but was told to only add it once the water is clear. The salt content should come up because we had added salt about 1 hour prior, as mentioned. Should I just wait a couple of more days to see if it clears up? I was told the water should be at 70 degrees Fahrenheit for the SWG to function properly? I read the manual and it says 50 degrees. My aqua rite indicates the water temp to be at 63, last I checked, though the temperature has been cooling over night. We are expecting some hot weather for the next few days though. Thoughts? Suggestions?
Thanks!

 

[WestSidePool]

First, Welcome to TFP.
Next you'll want to read everything in Pool School.
Your going to want to get yourself a good test kit to be able to know what's going on in your pool. The recommended kit here is the TF100 it's a great kit and you wont regret buying it. It's sold by the sites owner Dave (duraleigh) so you can have confidence in it.

Going by the results from the pool store your going to want to get your stabilizer up and your TA down.
You can add stabilizer (CYA) now, but you'll want to add it slowly, since it can take up to a week to register on test results.
As for shocking, it's a process, not a product. You have to keep at it until the pool passes an over night chlorine loss test.
Again this is all listed in Pool School. You have to constantly keep your Free Chlorine level high enough to shock your pool until you pass an over night chlorine loss test. You can't just put the powder stuff in the pool once and think it can be done.

Since your Stabilizer (CYA) in so low you don't need much in the way of chlorine/bleach to shock and maintain that level, but your going to want to get going on it. You also need to brush everywhere sometimes more than once.

These are the numbers you should be trying to shoot for to maintain a nice pool. Again these are guides and will flucuate based on your pool, but it's a good reference.
Vinyl with SWG
FC 3-5
pH 7.5-7.8
TA 60-80
CH 50-300
CYA 70-80

 

[JasonLion]

Welcome to TFP!

Assuming CYA is really 10, you should go ahead and raise it a little right away, and then more when you have finished cleaning up the algae. It is simplest to get rid of algae when CYA is around 30 or 40, so I suggest you add enough CYA to bring the level up by 20, and then wait to add more.

You don't want to wait to see what happens, you want to make sure you really killed all of the algae. Otherwise you will most likely be right back where you are now by this time next week. You want to add enough chlorine manually to make sure you get to shock level at least twice a day.

The SWG isn't going to be able to keep up with the chlorine demand until the CYA level is much higher. It will work best when CYA is around 70 to 80. So you are going to need to manually add some chlorine each day, algae or not, until the CYA level comes up.

 

[poollover2012]

Thanks for all the info so far! So I went ahead and added some stabilizer this morning to try to bring it up to about 40 or so, hopefully. My salt content seems to be at 2900ppm, according to the aqua-rite, which is set on "auto" and at 50%. The pump is running 24/7. Should I aim for a shock FC of 10 by adding some bleach? Need I add more salt?

 

[duraleigh]

If you added stabilizer to get to 40ppm, then you re-consult the FC/CYA chart to find that shock value is now 16ppm of FC

 

[poollover2012]

If you added stabilizer to get to 40ppm, then you re-consult the FC/CYA chart to find that shock value is now 16ppm of FC

The SWG chart didn't list a CYA level lower than 60, so I wasn't sure. The pool calculator is telling me i need to add 17 Litres of bleach to go from 5 to 16 FC. If I need to reach this level every day until the water clears up, that's a heck of a lot of bleach!

 

[duraleigh]

If I need to reach this level every day until the water clears up, that's a heck of a lot of bleach!

Hopefully, your FC will not drop to five each day so you won't have to re-add so much.

Regardless, you have no choice. If you do not maintain your FC back up at shock level, you will have a difficult time clearing the pool.

 

[WestSidePool]

Seeing as you just added stabilizer, it's probably not at 40 yet. So your shock level may still be lower than 16.
I just ran the numbers in the pool calculator based on your pool size of 25,748 US gal.

since your using the metric system can I ask where you are located?
Converting the numbers from US to metric you are correct 17 liters or 6.1 (2.85 liter) jugs of 6% bleach just to get up to shock level, but you wont need to add that every day, You have to add enough to keep it there until you pass the overnight chlorine loss test.

The SWG can help maintain the level, but it wont be able to raise your chlorine fast enough to shock the pool.

 

[poollover2012]

I'm located in Toronto, Ontario, Canada. It was a liquid stabilizer I bought which apparently takes about 24 hours to take effect? I'll be adding some bleach tonight but won't be able to test for CYA as I don't have a comprehensive test kit. Currently I have a PH and Chlorine test kit only. Maybe I'll aim for a target shock FC of 12-14. How long after adding bleach can I test the chlorine level? The next several days I have time only in the early morning or late evening to devote to the pool.

 

[duraleigh]

Seeing as you just added stabilizer, it's probably not at 40 yet.

Within 24 hours of adding it to the pool, you use the calculated dosage of CYA, whether or not the test results shows it. So use the 40ppm. It actually may not be QUITE all in there but assume that it is. Shock to 16 FC

You can test for chlorine usually 30 min to an hour after adding. It may not all be there because chlorine starts being consumed the instant it is introduced into the pool.

 

[poollover2012]

Update:
I bought some bleach last night and using the pool calculator I poured in the recommended amount to bring the FC to 16 from 5. However I don't have a test kit capable of testing for FC levels higher than 3, so until I order something better, I'll have to rely on my pool supply shop. Seems my CYA wasn't as high as I thought either because here are the results from this morning's test:

Stabilizer 25
Mineral 3200
FC 3.5
pH 8.2
Acid 3
T.A 130
Adj T.A 130
C.H 90

I bought some muriatic acid to bring down the pH. Is it ok to add it while I'm shocking? This shop recommended I lower it. One thing I noted is that it's not cheaper to buy bleach over liquid chlorine around here, not when you factor in concentrations, so I bought 20 litres of liquid chlorine The shop recommended I dump all of it in, and then after a couple of days possibly dump another 20 litres. Their philosophy was not to bring FC up to a target and keep it there, it's basically to dump a Crud load of chlorine until the water clears up. They did say to hold off adding any more stabilizer until the water clears up.

 

[JasonLion]

Using lots of chlorine all at once can damage your liner.

If you have a time while FC is on the low side, then go ahead and adjust the PH down. You can lower PH any time your PH test is working correctly, so you can check to see where the PH ended up and what other adjustments you need to make. The PH test is often wrong when FC levels are high. If FC is around 3 to 4, then the PH test should be fine.

 

[poollover2012]

Thought I would post some progress pics. Now the water was a lot darker and dirtier when I first started but I neglected to take pictures. The most recent pic was jut taken. Last night I dumped 20 litres of liquid shock. The shop had run out of chlorine so gave me a good deal on the shock stuff. Again, I'm not seeing the financial benefits of using bleach because I'm getting this stuff at good prices. Now, should I give it another day or so or continue shocking the pool. I'll be able to get another set of tests done tomorrow. I did add some muriatic acid to bring down the pH a little. I'll test for that later. It's been 7 days since we first removed the cover. I believe I could have been at this stage in half the time though, knowing better. Thanks again.

 

[chem geek]

Again, I'm not seeing the financial benefits of using bleach because I'm getting this stuff at good prices.

Great pics! There's nothing wrong with using chlorinating liquid if the pricing is good. That's why I use in my pool for the same reason and because it's half the weight to carry compared to bleach.

As for when you are done shocking, you should maintain shock level until three criteria are met: 1) your pool is clear, 2) your overnight Free Chlorine (FC) loss is <= 1 ppm FC and 3) your Combined Chlorine (CC) is <= 0.5 ppm.

 

[poollover2012]

Thought I would post another update! Now my sand filter was taking it's sweet time to clear out the water ( it didn't help I left the winter plugs in for a few days), so I thought I would add some DE to help it along the way. WOW! This stuff is fantastic! After only a couple of hours I saw a huge improvement. I had already tried a clearing agent, "Nu Blu" from my local pool store but didn't see a noticeable improvement, but this DE stuff? Simply phenomenal. Guess they don't really want you to know about this trick. I think anyone with a sand filter should give this a try if they've got cloudy water. I can't wait to see the result tomorrow morning.