calvin.m16
Well-Known Member
0.01 grams (10 mg) per gallon of 52-58% CalHypo powder will give you 1-2 PPM chlorine (example ~0.3 grams per 30 gallon reservoir)
0.002 grams (2 mg) per liter of 52-58% CalHypo powder will give you 1-2 PPM chlorine (example ~0.28 grams per 100 liter reservoir)
I've used the search function on here plenty of times to see a lot of different answers on how much pool shock (calcium hypochlorite) to use for reservoirs to be sterile within a safe, plant-friendly (1-4 ppm range). I purchased 2 different brands of Chlorine test strips and two different packets of Calcium Hypochlorite (easily found at any pool section in both 52% and 58% formulations).
The absolute best amount I found for simple math is 0.10 grams per 10 gallons of water to achieve 1-2 PPM of free chlorine. So a 5-gallon bucket, you would use 0.05 grams of Calcium Hypochlorite powder to achieve 1-2 PPM of chlorine.
The only reason I say 1-2 is the strips I have range from 0-1, 1-2, 3-4, 5-6.
That said if you overshot a little bit, maybe for example ±0.02 grams *accounting for shitty scales*, then you would be okay and should still be below the max recommendation of ~5 PPM free chlorine.
The reason 5 ppm is known to be safe is a lot of hydro growers have proven using heavily chlorinated municipal water works fine.. Preventing root rot, beneficial/anaerobic bacterial growth and still not killing plants or causing issues.
Obviously you need a very accurate scale for this, preferably a milligram/microgram scale. Found easily on Amazon for $10-40 depending on quality/brand... I personally give my 30-gallon reservoir 0.30 grams of 52% Calcium Hypochlorite every fill to prevent algae blooms and other shit as my reservoirs will stand sometimes 72 hours after mixing between waterings. It is also smart to always add a small water pump or airstone to move the water at all times if it's not being used within 24 hours.
Another benefit I noticed is fungus gnats no longer appear in my garden. The sterile environment provides no fungus for them to thrive on, but keep in mind this also means nay mycorrhizae or beneficial fungi will also be killed.. In my garden this hasn't caused a change in yield/quality at all. I used to think compost teas and organic inputs made the weed taste better but that seems to be complete bro science. N, P, K, Mg, S make terpenes in cannabis synthetic or organic, the plant doesn't know the difference.
