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Do I need to add CalMag to tap water?

Discussion in 'Newbie Central' started by TelecomJunkee, Dec 30, 2010.


    TelecomJunkee Member

    I am using filtered tap water and the PH is a perfect 6.5-6.8 If the PH is right, does this make the CalMag content right? Will adding CalMag to tap water going by the recommended dosage hurt a plant if the water does not need it? Thanks in advance!!

    sparkabowl Active Member

    Just because pH is OK, doesn't mean your CalMag level is OK, especially in filtered water. Adding CalMag won't hurt unless you make your water too high in total dissolved solids, which you won't if using only CalMag at recommended doses in filtered water.
    stuckonsticky and weednurd420 like this.

    wannaquickee Well-Known Member

    to much cal/mag could cause a def of other nutrients! in most cases adding cal/mag to tap water is not needed. tap usually in most case has more than enough available for use.

    what is your ppm levels of your water.
    az2000 likes this.

    TelecomJunkee Member

    Thanks Sparka! Should I be adding it to all of my H2o mixes, i.e. Fertilizer Mix, Supplemental Nutrient Mix, regular H2O? I haven't been using CalMag much since going back to tap water and everything has been growing great, but I want to do everything I can to ensure maximum fruits from labor. You know the drill, thanks again.

    TelecomJunkee Member

    Thats what I am afraid of Wanna, if it aint broke don't fix it right? PPM in reference to my tap water? I think that means parts per measure and I do not know what this is for the tap water. As previously stated the PH is 6.5-6.8

    wannaquickee Well-Known Member

    parts per million for sure. but if its working for you then dont change it. but experimenting could help you in the future to increase your yield :D..trial and error for sure...

    you should always have a ppm/ec meter on hand to measure your nutrient content.
    az2000 likes this.

    DobermanGuy Well-Known Member

    ppm (parts per million) is simple and essential if you want maximum yields. 10-20 ppm is R/O water. My tap water is around 500 ppm. This is the amount of stuff (everything from iron to calcium to potassium, EVERTHING) in relation to water. RO water would have 10-20 parts other than water (H2O) per million.

    woodsmaneh! Well-Known Member

    Cal-mag is good stuff if used right. One of the first signs of too much Cal-mag is the leaves are a dark deep green, not good. I found that using 1/2 of what they say works best for me. On the whole if you are using it all the time I think you need to look at what your feeding them. Cal-mag is like aspirin you only use it when you have a headache.
    Snow Crash

    Snow Crash Well-Known Member

    Using Cal-Mag Plus at 5ml per Gallon will add around 90ppm to 120ppm to your water. Around 40ppm of calcium, 30ppm of nitrates, and 20ppm of magnesium. Most nutrients are designed for tap water with 150ppm to 200ppm, usually containing a variety of minerals in low concentration with a good deal of Cal-Mag already.

    Personally, my tap water is soft, coming in around 60ppm. When it gets broken down, it is really very little calcium. This requires that I add about 5ml per gallon EVERY time I add water so I can get my tap water up to a level that my nutrient brand is designed for, and to prevent deficiency.

    Without knowing what is in your water already you're really blind. The fact that your water is acidic (while most are more alkaline) actually indicates that it may not be the highest quality. Perhaps with very high levels of chloramines.

    Your water company should be able to provide you with a report of your water quality free of charge. These usually contain readings in ppm that should let you know, even without a meter, about what your water has in it. Then you can adjust your Cal-Mag usage based on that.

    weednurd420 Well-Known Member

    dude your pic is tripping me out lol

    @[email protected] New Member

    90 ppm, how do i calculate this into the prescribed ppm dosage, im supposed to add 700 ppm and using tap water at 90 ppm, my confusion here is that if i add the recommended dosages to give me 700 ppm i will end up with 790 ppm, so how would i add 610 ppms to the batch, im so confused, any help with this is GREATLY appreciated

    Craig1969SS Well-Known Member

    Add molasses 1-2 tsp per gallon if u want a cal/mag supplement. I can also say don't be treating something that isn't there. tap water is underrated and criticized for being this or that. Use it side by side with your RO supplemented water. You'll see no difference, nada, none. Keep it simple

    hotrodharley Well-Known Member

    Calcium and magnesium in tap water are large molecule and cannot be taken up by your plants. Therefore they help speed lockout.

    bearkat42 Well-Known Member

    I don't add anything. My water comes straight from my faucet into my drip system.

    hotrodharley Well-Known Member

    Lucky you. Most are not so fortunate.
    bearkat42 likes this.

    hotrodharley Well-Known Member

    "What is that 150+ ppm comprised of, anyway? Often it consists largely of calcium and magnesium. You might think, “Great—I needed that anyway!” but you would be mistaken. The particular forms of calcium and magnesium that are contained in municipal water are often the large-molecule variety—and large molecules cannot fit into the small pores on plant roots. They are not absorbed by plants, but instead just attract other calcium molecules with a snowball effect." (Causing lockout which is actually salt build up on the exterior of your roots effectively blocking uptake of anything -my note)


    Use RO water if your EC/PPM is high because it is invariably Ca and Mg as the major "hardness" factors.Instead use Cal-Mag in RO as it is calcium acetate or calcium nitrate which the plants CAN use quickly.
    Enigmatic Ways likes this.

    @[email protected] New Member

    plz help with my question, im so confused with this, can someone plz help with the question i posted, PLZ

    Sweeve Active Member

    @@[email protected] ....um yea i would just add enough to make it even with 700 ppm....instructions not on the box???

    @[email protected] New Member

    sweeve, thanks for the reply, im trying to wrap my head around this ppm stuff before i get started have a couple of plants that are about to get there first feeding and want to learn as much as i can............ now as far as what u said, im assuming ur saying to just add enough nuets to my 90ppm tap water to equal 700 ppm,

    Craig1969SS Well-Known Member

    Man I agree with a lot of your contributions and thoughts here. I've learned from your replies but you're splitting molecular hairs here. The biosynthesis in the soil is being overlooked, enzymes and precursors produced by both the bio and plant make substances available in absorptive form.
    hotrodharley likes this.

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