New pool owner need help to reduce cc level

[bluesage]

I just bought a property with a pool one month ago, 3 weeks ago i found black algae in the pool. then pool shop sold me a bottle of algae acid to remove them, it failed.

I searching by google and found this place, tried to find the solution. And i SLAM my pool by 10 kg Chlorine powder from Bunning (AU) one 17th of Sep, after 3 days ,the black algae gone. one week the water became clearly from cloudy.

I taken a bottle of water to pool shop for text (i would buy a text kit from US). all the result is fine except FC is 16. I know it should be normal. BUT today the result is
fc 15.92
cc1.6
tc17.52
ph7.9
cya55
ta75.5

i running pump with swg about 11 hours a day after the algae gone.

Is it anything i did wrong? i think i add too much Chlorine into the pool, it is 50000L salt water pool.

Do i need slam the pool again to reduce cc level or just waiting the fc and cc level down.

Thank you very much for your help

Sorry about my English.

Bo

 

[KenGood]

Others will comment as they wake up. But to start, welcome to our forum. I think that you did not slam long enough initially. You have to do it until all three criteria for completion are met. If CC is 1.5 that means you have to slam. Be certain you follow the procedures as set out. This forum recommends using liquid chlorine for slams. Granular will bump up you CYA pretty quickly. Good luck and we love pictures.

 

[bluesage]

Thanks Ken, after black algae gone i got cc at 0.5,fc is over 16 from pool shop,and just add some acid and tap water into pool ,after a week the cc level is 1.5,fc still 15, i running swg and pump 12 hours a day. is there any reason cc reach this high?

Thank you very much man.

 

[KenGood]

With a CYA of 55, your slam target is 22-24. You keep it there until you pass the overnight test. It is called OCLT test. Also, for a salt pool CYA should be minimum of 60, which would make slam target 24. But since you used granulas I bet your CYA is higher than tested because it can take up to a week for new stabilizer to appear on a test. So I think first slam was not long enough or at a high enought chlorine value so all the bugs were not killed.

 

[Isaac-1]

Being a new pool owner I am not sure what exactly you know and what you don't so this might be obvious, but I am going to say it anyway, your SWG is a Chlorine source, so is helping to maintain your FC at an elevated level. If you turn it off for 24 hours or so, your FC should fall close to the suggested range. As to your CC level it is hard to say, we don't tend to trust pool store testing that much around here, but given it is what we have to work with for now, the question would then be are you seeing sane trending from previous tests, how was CC prior to your attempted SLAM process, how has it been since then?, is there a trend to the test numbers? Also what is in the dry chlorine product you used, if it was dichlor or trichlor based then your going to have some major CYA problems, if Cal-Hypo maybe less so, but since you don't list the size of your pool or the CH test results that is again hard to say. The reason we strongly suggested use of liquid chlorine / bleach for the SLAM process is all the dry chlorine products have negative secondary effects which can show up quickly using those high quantities at once.

Ike

 

[bluesage]

thank you very much for you guys help ,i would order a text kit from us. honestly i do not trust pool shop as well after they sell a algaeacid to me. it totally useless and very expensive.

before the slam , CC level always in the range most time is 0.5. after slam the first result is still 0.5, during a week closing , add some water and acid.
the text result is 1.5.

I us this product http://www.bunnings.com.au/hy-clor-10kg ... e_p3090194, i am not sure what is the base of this one.

the pool is 50000L with swg and sand filter.

thanks again

 

[Jeetyet]

The product referenced is Cal-Hypo 65%. Adding 10kg to a 50,000L pool would raise FC by about 130ppm and CH by about 90. So, of the granular/powdered chlorine products at least you used the least "harmful" one. Your CYA level should be the same as before adding the Cal-Hypo. Whether or not the pool store's tested level is accurate or not is another matter.

 

[Isaac-1]

Even if you can't get a good test kit from the U.S. are there any drop based DPD Chlorine (shades of the color pink on the comparator, not OTO Chlorine which are shades of yellow) kits where you live, if there are you could at least test the range of your CC, and get a ballpark reading on FC