how much bleach do you add to pure water to raise the ppm to 3 and also to 7?

Question

the bleach availbale is ultra clorox with the active ingredient sodium hypochlorite at 6.15%. and i am cusious how much to mix with 500 gallons of water to obtain the proper ppm of 3 for algae reduction in a drip watering system.

Answer 1

Assuming that the sodium hypochlorite (NaOCl) has a concentration of 6.15% (or 6.15 parts per hundred), then a ten-thousand-fold dilution will give you a 6.15 ppm (parts per million) solution of bleach.

BUT! You want 3 ppm...so the dilution factor is 20,500. This means you need to mix water to bleach in a 20,500 to 1 ratio. For a 7 ppm solution of bleach, the ratio is 8,786 to 1.

So, if you're using a 500 gallon tank, and making a 3 ppm solution, add 0.02439 (92.3 millilitres, or about 3.1 fluid oz.) gallons of bleach and top off with water. If you need the 7 ppm solution, use 0.05691 gallons (215.4 millilitres, or about 7.3 fluid oz.) of bleach and top off with water.

That ought to take care of any algae.

Answer 2

4ppm's worth.