Pool now light green from algae

[ryancervenka]

Help...pool was overrun with some green algae this past week. I installed an inline chlorinator and was experimenting with the levels when the chlorine level dropped down to 1ppm. Not to mention the pool temp got up to high 80's. I shocked the pool overnight with DiChlor and got the levels up to 12 ppm. I have the pump running continuously and I brushed the walls. How long will this take to clear up? What else should I do?

CH: 12ppm
pH: 7.4
TA: 150
CYA: 40

 

[PaulR]

What kind of chlorine test do you have? I assume your "CH" means chlorine, which could be either FC (free chlorine) or TC (total chlorine) depending on the test type. (Usually we use CH to mean Calcium Hardness.)

The dichlor will raise your CYA almost as much as your FC, with CYA already at 40 you probably want to lay off the dichlor. Usually liquid chlorine or regular bleach (same stuff, different strengths) winds up being the cheapest chlorine source, and adds nothing bad.

Check out the Defeating Algae article in Pool School, it should help answer some questions.
--paulr

 

[ryancervenka]

The FC is now 10 ppm and I just got done brushing/vacuuming again. Water is still light greenish color in deep end only. The FC is holding overnight. I used Dichlor because I bought 50# at beginning of season before I found this site! I will do things differently next season. How long will this process take? Is the algae dead or do I need to keep FC levels high?

 

[frustratedpoolmom]

I agree with Paul. You really don't want to keep using Dichlor, your CYA will get too high and you'll end up having to drain water out to lower the CYA. It will keep - just store it in a cool dry place and you can use it to occasionally boost CYA while shocking, if needed.

Using liquid chlorine/bleach, keep your pool up to shock level for your CYA - refer to the cya chlorine chart in my sig - and follow the instructions in Defeating Algae, the link to the article he gave you.

Every pool situation is unique, we can't put a timeframe on it. Shocking is a process, not a one time event. You need to be diligent testing the FC levels and adding liquid chlorine a.k.a. bleach frequently until:

Your FC holds overnight or you lose 1ppm or less (testing with the FAS-DPD test)
Your CC is .5 or less
Your water is clear and sparkly.

If you don't meet the three criteria you aren't done shocking.

 

[ryancervenka]

wife told me pool is still green today...had her buy liquid chlorine at grocery store...i'll brush/vacuum today and then throw liquid chlorine in at night right?

 

[reebok]

pool-school/shocking_your_pool
pool-school/chlorine_cya_chart_shock

you need to be staying at shock level for your cya level with the pump running.

 

[ryancervenka]

good to go now...used the liquid chlorine and kept it in shock levels until cloudy...added clarifier and now it's crystal clear. the BBB method is the way to go! Thx for the help

 

[reebok]

someone else will have to "clarify", but you're supposed to keep shocking until the water is clear. you shouldn't need clarifier. what about an overnight fc loss test? you need to be losing 1ppm or less. and cc's need to be below .5. I just don't want you to have an algae bloom sitting there waiting to happen, which you may.

 

[Guest]

good to go now...used the liquid chlorine and kept it in shock levels until cloudy...added clarifier and now it's crystal clear. the BBB method is the way to go! Thx for the help

Doh! The BBB method requires no extra products like clarifiers.

If you had to add a clarifier the pool isn't done.

We are here when you come back because the algae returned.

 

[ryancervenka]

fc held overnight..water looking good but not crystal clear in deep end so i added clarifier i had left over from before.