Calcium and Mag PPM

S

S.Zombie

Member
Hey,

Am I right in thinking that the ppm for autos are as follows? Plants are doing well so far but I want to get the correct numbers.

Calcium: Between 150ppm - 300ppm (mg/L)
Mag: Between 50ppm - 75ppm (mg/L)

My water is currently:
Calcium 80 (mg/L)
Mag 23 (mg/L)

Pretty sure PPM is the same thing as (mg/L)

Thanks :)

Screenshot_20230413_171215_Samsung Internet.jpg
 
9

93OG

Well-Known Member
I’m pretty sure 1 Ppm is .1 ml/liter
1 ML or 1MG is 1/1000 of a liter
1 ppm is 1/1,000,000 0f a liter
 
S

S.Zombie

Member
93OG said:
I’m pretty sure 1 Ppm is .1 ml/liter
1 ML or 1MG is 1/1000 of a liter
1 ppm is 1/1,000,000 0f a liter
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Hm, that makes sense when you write it out like that. Now I'm scratching my head as everywhere I search seems to say they are the same.

If you're correct then my plants would appear to have been getting a grand amount of cal and mag :/
 
S

S.Zombie

Member
rkymtnman said:
if you go by Lucas formula #'s (an old school nute profile for cannabis) , Mg should be around 60ppm. and generally you want 2:1 or 3:1 Ca to Mg ratio too
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Thanks, that would be about right for what I was thinking.

Just worked out that:
1 Litre of water = 1kg
1kg = 1000g
1kg = 1,000,000mg

Therefore, I think it's correct that: 1ppm = 1mg

Any idea if the other nutrition in that water is too high or low?
I am wondering about doing a 1:1 mix with RO water and using CALMAG to rebalance cal & mag, this (I would assume) would halve the other nutrients too.
 
S

S.Zombie

Member
rkymtnman said:
can you grow houseplants with your water? if so, you should be fine.
Click to expand...
Honestly, I've no idea. Decided it would be easier to use bottled water for this grow as my tap water is heavily chlorinated and full of lime. We only drink from our RO tap and bottled water here.
I'm fairness the plants look pretty decent to me, very slight purple tint on some leaves which I think is down to getting a bit cold at night lately, which I have sorted now.

I'll try the 1:1 mix with RO + calmag and see how they go.
 
rkymtnman

rkymtnman

Well-Known Member
when i started many years ago, i bought RO water at the grocery in 5 gal jugs. did that for a few years and slowly started mixing in my well water until i finally got to 100% well water.

it does eliminate your source water as a possible problem when you are first starting out
 
Missouri Green

Missouri Green

Active Member
4:2:1 K:Ca:Mg 200:100:50 roughly.. i just did a grow where i cut the Ca one hundred percent 4 weeks before harvest... ie at first pistil wither... many things were changed this run but GD when i tasted this at 10 days drying .... OMG . amazing
 
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