Highly-modified SLAM routine

[Canucklehead]

Hi all. Time to shut down for winter.
We're just back from a month's vacation during which the house-sitters allowed green algae to make themselves a home.
I'm slowly transitioning to the TFP system. I will finally have a Taylor test kit in 3 days (when I take a drive to Bellingham, WA) and I've just used up the last of my chlorine shock. I know, it's all bad. Next year I want to try TFP's methods, all the way. For now, it's pretty much seat of the pants.
I've had to assume a CYA of 40 (what the pool shop said it was, 6-8 weeks ago.) I did a shock 2 days ago and again yesterday, about 6 cups each time. The test strips say my FC & TC are 10, higher than I targeted. Oh well.
pH is 7.5-ish (best I can tell with the strips.) The water is less green, but still green. Very cloudy. Temperature 68°F. Pump running 24 hours/day. System pressure never changes much: 19.
I'm prepared to wait this out, the clearing the water, but I don't remember a shock taking this long before, to clear the green color. Any suggestions will be gratefully received, thanks.
Vinyl pool, 25,000 US gal.

 

[borjis]

Accurate test kit results are key to success. Without them you don't really know if it will be successful or a failure.
What the pool store and guess strips say will likely not help.
Pool store methods mixed with tfp doesn't really work, you have to follow one or the other.

 

[mknauss]

Add 5 ppm FC worth of liquid chlorine to the pool each evening with pump running until you get your test kit.

 

[Canucklehead]

Add 5 ppm FC worth of liquid chlorine to the pool each evening with pump running until you get your test kit.

Now there's some advice that shows promise. A couple of questions, if I may:

(1) Will that move not further increase an already quite high FC? Are you saying that it's not an issue, since the green algae are still evident and still need to be eradicated?

(2) A more practical point: the labels on the bleach products I've been inspecting don't state what their concentration is. This is Canada, so perhaps our rules are different, but it boggles my mind that I cannot determine how much FC I will be adding, when I add bleach.

(3) I used to be good at math, but "add 5ppm FC" will tax my neurons, even if I can figure out the bleach concentration.

Thanks!

 

[gonfishin]

If the pool store test for CYA is correct at 40, SLAM level is 16 FC. Guess strips saying 10, means you don't have to worry about adding 5ppm per day of chlorine as you still most likely won't reach SLAM level.

Not knowing the strength of the chlorine you're adding is problematic. The PoolMath app and the web based version (see "Old PoolMath Webpage" link at the bottom of each TFP web page) need to know the chlorine strength in order to guide you in how much to add to increase chlorine by 5ppm (or any other amount).

 

[ajw22]

If the pool store test for CYA is correct at 40, SLAM level is 16 FC. Guess strips saying 10, means you don't have to worry about adding 5ppm per day of chlorine as you still most likely won't reach SLAM level.

Guess strips max out at 5 or 10 ppm so there is no way of knowing the real FC level.

It is all a guess until tested with a better test.

 

[Canucklehead]

D'oh! I guess I can't even figure out how to make the Pool Math calculator work for me; I got 5-7ppm for the SLAM FC. I'll get there. I don't need more people telling me: I already know I'm not doing it right.

I do like the way you folks make me think. Rather than reading bleach labels, I just went online to find this (hopefully accurate) description:

"Concentrated bleach is an 8.25 percent solution of sodium hypochlorite, up from the “regular bleach” concentration of 5.25 percent."

I'm wanting to add 5ppm of FC: If the bleach is 5.25% (5.25 gm per 100ml), that's 52.5 gm/litre. 5gm/million litres. So I only need to add to my 85,000L pool, 5 / 1,000,000 * 85000 = (approx) 4.5 grams FC or (approx) 100 ml of bleach? That's all? Someone please check my math.

 

[mknauss]

You need to add 5 liters of your bleach to attain 5 ppm FC in your pool volume.

 

[Canucklehead]

Wow. mknauss, with people like you around, I don't need math. Much as I would like to know where I went wrong, I will easily remember that 1 litre = 1ppm FC, for my pool.

Thank you so much.