When diluting hard water with RO is extra magnesium via epsom salts typically required?

Hi all, greetings from rural Waterloo region, ON!

I live in a part of the province that feeds a lot of the rest of our province. There are farms and fields in every direction that as far as I know do just fine with the regions tap water.

But this being said -- it's extremely hard out here. Around 330 PPM from the tap currently.

I saw in another thread that target PPM for cannabis is somewhere around 100, so I use 10L RO to 5L Tap and this puts me right around 100-115PPM.

My question is this: without knowing the exact concentrations of calcium and magnesium in our tap water (I've checked the regions website, sadly they only test for heavy metals and lead), and knowing that we have extremely hard 330PPM tapwater diluted down to around 115PPM with RO, would supplementing additional magnesium be required with epsom salts?

I just picked some up after seeing conflicting forum posts online and am still unsure on this

Big thanks again for any advice, cheers!!

deimos phobos said:

Hi all, greetings from rural Waterloo region, ON!

I live in a part of the province that feeds a lot of the rest of our province. There are farms and fields in every direction that as far as I know do just fine with the regions tap water.

But this being said -- it's extremely hard out here. Around 330 PPM from the tap currently.

I saw in another thread that target PPM for cannabis is somewhere around 100, so I use 10L RO to 5L Tap and this puts me right around 100-115PPM.

My question is this: without knowing the exact concentrations of calcium and magnesium in our tap water (I've checked the regions website, sadly they only test for heavy metals and lead), and knowing that we have extremely hard 330PPM tapwater diluted down to around 115PPM with RO, would supplementing additional magnesium be required with epsom salts?

I just picked some up after seeing conflicting forum posts online and am still unsure on this

Big thanks again for any advice, cheers!!

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Are you talking about water from wells? Or do you have regional municipal water? A well would be fine but if it's "treated" and piped to your house I wouldn't use it. Do you have an RO system in your house?

300 ppm isn't high. Mines ~250-300
I'm right around your area. Bought an ro machine. Barley ever use ro other than making coffee. Nothing wrong with using tap.

if i remember correct RO strips the magnesium out

Beeswings said:

Are you talking about water from wells? Or do you have regional municipal water? A well would be fine but if it's "treated" and piped to your house I wouldn't use it. Do you have an RO system in your house?

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Just municipal water supply. Farmers thrive where I live on this same water but I'm guessing that's irrelevant to cannabis .. I was mostly looking to treat it with vitamin C to reduce the chlorines and then dilute with RO to an acceptable level, then pH the water to a point the plant can uptake the naturally occuring rich minerals

Jjgrow420 said:

300 ppm isn't high. Mines ~250-300
I'm right around your area. Bought an ro machine. Barley ever use ro other than making coffee. Nothing wrong with using tap.

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Amazing! Are you out near Waterloo too? Or you meant "I'm around your area" regarding tap ppm

Thanks again man, and same thing, I rarely use our RO but do have the system in place

i would fought if the city is a lot of farm lands and they use it it would be good for weed

deimos phobos said:

Just municipal water supply. Farmers thrive where I live on this same water but I'm guessing that's irrelevant to cannabis .. I was mostly looking to treat it with vitamin C to reduce the chlorines and then dilute with RO to an acceptable level, then pH the water to a point the plant can uptake the naturally occuring rich minerals

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I'm my opinion, I'd just run all RO water and add what you need to it as far as Cal mag and whatever else. You never know what is in the municipal water and it can change on you at any time. Just my 2c.

amneziaHaze said:

i would fought if the city is a lot of farm lands and they use it it would be good for weed

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The farmers probably have wells or something else, if they grew vegetables on municipal water they would be quite expensive vegetables!

deimos phobos said:

Hi all, greetings from rural Waterloo region, ON!

I live in a part of the province that feeds a lot of the rest of our province. There are farms and fields in every direction that as far as I know do just fine with the regions tap water.

But this being said -- it's extremely hard out here. Around 330 PPM from the tap currently.

I saw in another thread that target PPM for cannabis is somewhere around 100, so I use 10L RO to 5L Tap and this puts me right around 100-115PPM.

My question is this: without knowing the exact concentrations of calcium and magnesium in our tap water (I've checked the regions website, sadly they only test for heavy metals and lead), and knowing that we have extremely hard 330PPM tapwater diluted down to around 115PPM with RO, would supplementing additional magnesium be required with epsom salts?

I just picked some up after seeing conflicting forum posts online and am still unsure on this

Big thanks again for any advice, cheers!!

Click to expand...

330 isn't bad. Mine is 650, thats getting a bit high.

Never heard of a 100ppm target. Did they give a good explanation??? Sounds like personal preference for a specific situation.

300ppm should be 0.6 ec, not high but not low to start with, 0.3 is somewhat ok when your trying to build your own solution.
You have 0.2 ec which is good if you plan to make water solutions. I think add some more tap to that mix to not worry about Ca and Mg because when people start adding them in unknown qtys it can cause some issues.
If you do choose to add, make sure to go up slow in order to evaluate changes to your plants.
RO or distilled water with perfect nute range will have explosive results, sorta same with RO and coco/peat with organics just without worries.

Beeswings said:

The farmers probably have wells or something else, if they grew vegetables on municipal water they would be quite expensive vegetables!

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We live in the area of an environmental disaster in the WW2 days and our water arrives via pipeline, because the native aquifers are still not deemed safe!
I'd assume they are all using the same water from the region, at least until out of this geographical area

1212ham said:

330 isn't bad. Mine is 650, thats getting a bit high.

Never heard of a 100ppm target. Did they give a good explanation??? Sounds like personal preference for a specific situation.

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Not really - the crazy thing I have learned, as a newbie, is that the forums can be both a good or bad source of information.. and above all else - incredibly confusing and it seems very few growers seem to agree on things.. It's really weird

I can't tell you HOW MANY occasions, on various forums, I can see guys saying they pH or don't pH their water when growing in soil. One guy says its extremely important, another guy says clackamas coots told him it's not important. Who do you believe? The guy saying pH your water or the plant can't take up the native minerals in your tap source. Other guy says oh boo hoo, that's not important in soil. Like who's right, who's wrong?

Pretty much same scenario with the PPM thing. One guy says the golden rule of indoor growing (not even joking, he called it this) is tap water must be 150ppm tops. Another guy in another thread says he grows with 550-650ppm water in the desert.. So I am 100% thoroughly confused

if you can see the burned out spongebob in my avatar, that's pretty much my face after researching something across the 5 or so big cannabis forums

deimos phobos said:

... One guy says the golden rule of indoor growing (not even joking, he called it this) is tap water must be 150ppm tops. Another guy in another thread says he grows with 550-650ppm water in the desert.. So I am 100% thoroughly confused

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For hydroponics, 0.3 EC is often cited as a goal; i.e. you rarely have to worry about the water composition if it's 0.3 EC or less.

For general growing info, a good book is far more valuable than trying to sift through the dismal forum signal-to-noise ratio in the search for legitimate info.

These two are excellent:

Billy the Mountain said:

For hydroponics, 0.3 EC is often cited as a goal; i.e. you rarely have to worry about the water composition if it's 0.3 EC or less.

For general growing info, a good book is far more valuable than trying to sift through the dismal forum signal-to-noise ratio in the search for legitimate info.

These two are excellent:
View attachment 5387688View attachment 5387689

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Thank you, I can look into those for certain!

I notice it says hydroponic and I grow in supersoil, would these still be a good choice? Thanks again

I’m in Cambridge where the ppm is around 600 out of the tap..I use 80% R/O then top it off with municipal water..just enough to bring the ph value to 6.0 after adding my nutrients.

Flash63 said:

I’m in Cambridge where the ppm is around 600 out of the tap..I use 80% R/O then top it off with municipal water..just enough to bring the ph value to 6.0 after adding my nutrients.

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Hey neighbor!! I come into Cambridge all the time, mostly for the beer and food at Gators Tail

Holy crap, 600 ppm! I wonder how yours is almost twice as hard, especially when you guys have a usable water source! Wow

What do you mean by "supersoil"? Is it a brand or kind of soil or did you make it your self following a recipe? What makes it super? The reason I ask is because if you have enough beneficial bacteria and microbes, you really can get away with not ever checking the pH. If you start with an unbalanced soil that is not a good environment for the little bennies to thrive, then you absolutely will need to watch the pH or the plants won't like it at all.

Beeswings said:

What do you mean by "supersoil"? Is it a brand or kind of soil or did you make it your self following a recipe? What makes it super? The reason I ask is because if you have enough beneficial bacteria and microbes, you really can get away with not ever checking the pH. If you start with an unbalanced soil that is not a good environment for the little bennies to thrive, then you absolutely will need to watch the pH or the plants won't like it at all.

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I believe it's just a term for pre amended soil

This is the exact product:


Although the name of the seller has living soil in the name I do not grow living soil, takes way too big of a container!

I water in microbes every few waterings but who knows if they're doing anything. I will feed molasses and fish Hydrosylate and a handful of other things too

deimos phobos said:

I believe it's just a term for pre amended soil

This is the exact product:

KIS Mix Blended Soil | Black Swallow Living Soils, Brantford ON

If you have listened to any of the podcasts on our website, you will have learned of Tad Hussey from KIS organics. Tad is based in the Seattle area, where he runs KIS Organics, a company that sells soil mixes, amendments and compost tea brewers to Washington State.

blackswallowsoil.com

Although the name of the seller has living soil in the name I do not grow living soil, takes way too big of a container!

I water in microbes every few waterings but who knows if they're doing anything. I will feed molasses and fish Hydrosylate and a handful of other things too

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It looks pretty good to me. If you're adding microbes as well you probably really don't have to worry about pH.