how does cal-hypo compare to bleach

[stualden]

I just found a chart that says 2 oz. of 65% cal hypo will raise FC by 1 ppm in 10,000 gallons of water. Assuming this is correct (someone please advise if not), then your situation requires

2 oz. * (25/10) * 20 = 100 oz. = 6 1/4 lbs.

so your 3 + 3 is probably good (although 6 at once might have been better).

The lingering question I have, however - help from a moderator here, please - is it valid to translate 16 fluid ounces = 1 lb. when you're talking about powdered cal hypo? I'm presuming that most people measure using a plastic cup marked in fluid ounces, not with a scale.

[Watermom]

I do not use cal-hypo in my pool, but, no, 16 fluid oz. cannot be equated with 1 lb.

[SoCalBoo]

Just a small note - if you use Cal-Hypo, you'll raise the calcium level. Probably not much of a concern for you with a vinyl pool and calcium level where it currently is. But if you have an SWG and/or heater, something to think about for the future (high calcium levels can cause scale, causing premature wear and tear).

[stualden]

I do not use cal-hypo in my pool, but, no, 16 fluid oz. cannot be equated with 1 lb.

Then could someone please provide the conversion factor?

[Poconos]

Here is the conversion. Just got a fresh 100# container of cal hypo and there was a big blue scoop included. 24 fluid oz --> 700 grams --> approx 1.5 pounds. Verified this with a scale too. The grams --> pounds (avdp) conversion numbers work out too. The ounce scale verified to be liquid too. So, one 16 oz cup full of the stuff is pretty close to a pound.
Al

[Watermom]

OK. I stand corrected. That is interesting that 16 oz (volume) does equal a pound (weight) for cal-hypo. This won't be true of all substances, however.