New to BBB, pool is clear, requires 2ppm ever day - algae?

flap152

Member
May 18, 2010
6
Montreal, Qc
Recently converted BBB pool is clear, but requires 2ppm every day. Still have algae?

Hi,

I moved to bleach recently but will not get a good test kit until late this summer. Previous years, I used to maintain 3-6ppm (targetting 4) with pucks in a chlorinator and OTO, fighting algea oubreaks (green all over) 4-5 times a season, usually after a short dip at or below 2 ppm when my chlorionator was empty and the solar cover was on for 3 days of no swimming. I usually recovered using Cal-Hypo powder, lots of brusing and vaccuuming. This year, after discovering this site and reading a lot, I realize that I probably had too much CYA or more precisely, never enough FC to compeletely kill algae and was always on the verge of an outbreak.

It's been a week since using only bleach and strips for measuring FC, PH, and TA (I also have CYA on one set of srtips)
My water has been really clear for 3 days, and I vaccumed the last few deposits of what seemed to be dead algae/dust on the walls and bottom, from the last outbreak 10 days ago. I was still at shock level (10ppm) 4 days ago, and overnight FC drops are at 2ppm (raise to 5 at night, measure 3 in the morning)

Here are my numbers and then the questions:

FC 3
PH 7.7 (overdid correction after last heavy rain brought it to 6.8)
TA 80
CYA 50 (pool store said 60, strips says 40)
Borate 5 (from qty added, not tested yet)

Is a nightly drop of 2ppm a sign that I am still battling something in my pool?
Do we really aim for 0ppm drop during the night? if not what value is acceptable?
Should I shock again?
At CYA 50, suggested Fc is at 4-8 ppm. Mid-point is 6 and seems high to me (wife looking over shoulder will notice the high value). Comments?

Thanks
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
20,447
San Dimas, CA (LA County)
2 ppm every day is normal. 2 ppm overnight is too high - something is consuming the chlorine, and it's not the UV light from the sun! Sounds like shocking is in order.

6 ppm in straight water is too high. 6 ppm with 50 ppm CYA binding to it is equal to much lower, perhaps 1 ppm in straight water. Certainly lower than your tap water if you're on a municipal water system!

I understand there are difficulties getting a decent test kit in Canada, but it really is essential that you get accurate readings. Don't you know anyone planning a trip to the states who may be visiting relatives? You could have a kit shipped to them.
 

PoolGuyNJ

TFP Expert
May 20, 2007
3,192
South Central NJ
Keeping the FC @ 10% or so of the CYA is the general rule of thumb. This is why watching CYA levels are important.

Do you have any CC? A greater than .5 reading would indicate a battle.

Scott
 

flap152

Member
May 18, 2010
6
Montreal, Qc
Richard320 said:
I understand there are difficulties getting a decent test kit in Canada, but it really is essential that you get accurate readings. Don't you know anyone planning a trip to the states who may be visiting relatives? You could have a kit shipped to them.
Wanted to keep my original post short so I actually erased my comment on test kit availability and price here. Don't get me started on this... :x I will travel later this summer and pick one up. Can I have it delivered to Disney world, you think? :)

Until then, what I do for reading TC in the 5-10 range is use my OTO, sometimes diluting 1:1 with spring water and double the value, or just put 2 drops and multiply my result by 2.5. Real precise... at least I'm good with math. :wink:

Thanks
 

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