I downloaded ph's old nutrient calculator off the cannastats site. I am using cns17 coco/soil grow and bloom, along with cns 17 ripe, gh liquid kool bloom, liquid karma, and protekt. When I put in the proper amounts to get the profile I want, the active element ppm is in the right range, but the actually ec of the mix is way too high that what I would normally use. For example, when I input 10ml bloom and 10ml ripe, the profile that comes up is; N-79 P-81 K-154 Ca-99 Mg-26 S-43 and at the bottom of the spreadsheet it says there are 484 ppm (@.7) active elements, but the actually ppm of the mix (@.7) is 1280 ppm. Thats almost 3x the ppm than the active elements. Do these calculations seem correct? If it is correct, what is causing all the extra EC ?
Did you do the math out based on per gallon converted over to YOUR res size for the correct amount to put in?
not sure but at least you have a baseline now. Use whatever you did as 100% (or max for flower ppm). So now you have a refereance point for where you are now. So 50% would give you 600~ ect... If you need 500 PPM just see what percent 500 is of 1200 and then use that percent of the nutes you put in last time. Never know with those online guides but as long as your meter is calibrated id go with that number over the internet
Personally, I don't trust any guidelines other than past just being that...a set of basic guidelines! Nute "calculators?" Same thing. Were your plants showing any stress symptoms or nute burn with the old mixture? Are they showing any with the recommended mixture, if you've used it? My own rule of thumb is to try to go somewhat with the guidelines, then possibly adjust up/down as needed if any plants show nute burn. (For example, I'm trying to use GH's "drain to waste" program with FloraNova right now, and I have two of my plants using less of the Bloom than they say, and one using more...I keep the rest of the ingredients about as recommended, but I keep the main ingredient just low enough to not do more than burn the tips of leaves; any more is too much. The point of hydroponics is to push the plants to m aximum growth but not make them unhealthy; I'm growing in coco, but similar enough as far as that goes.) My current ec is far-lower than recommended, partially due to using hard water for now. But I still have a little nute burn...since I've been going up and down. Every plant is different. Don't feel locked-in to any "program"; adjust the nutrients to what your plant is happy with! There are PLENTY of visual indicators as to what a good balance is with any nutrient regimen. Edit: And you quite-possibly have an ec/ppm conversion issue. Maybe those are the ppms, but any consumer ec/ppm meter is just measuring the ec, and converting to ppm. The "true" ppm can't be measured without far-more-expensive equipment, so the conversion isn't necessarily accurate...for example, I assume a conversion factor of 0.5 myself, from what my ec meter says; of course, different manufacturers will say 0.5, 0.64, or 0.7, even with the same meter. (Again, I'd go with recommended amounts, nudge them up and down as needed depending on growth and any signs of nute burn.)
It is not a feeding schedule or even a guideline. It is a spreadsheet program where you input the guaranteed analysis from each bottle of fertilizer you have, and then you put the amount you use into different spreadsheet cells, and it totals your approx. ppm for each element. My plants look just fine they way I am doing things now, but I am trying to dial in the best nutrient profile possible for a few strains. I notice little things like slightly bent leaf tips, or the minimalist of tiger stripes forming on the bottom leaves. I am just trying to improve... I am also growing in coco, so a question for you vapeos, what EC do you normally feed at, say three weeks into flower?
I have extremely hard water, so my numbers have to be taken with a grain of salt (and/or calcium carbonate...quite literally... ). On top of my 700µs/cm of hard water, I'm using around 900µs of GH nutes for two of my plants (they look sativa-dominant, I guess), and around 700µs of nutes for the third plant that's short and indica-looking. So around 1600µs for the first two, 1400µs for the other one (and half of that is my hard water!) I'd get an RO system if I was not moving in a couple months. I *suspect* (just from what I've read) that you could feed maybe 20 - 30% more than what I am, with RO water...the excess hard water crap doesn't affect the total ec as much as you'd expect. I can't say if the strains/sizes have anything to do with it, since I don't know enough about growing yet! But the small one has a trunk that's about 2/3 the size of the smallest of the other two...or about 45% of the total cross-sectional area. That's the small and bushy one that requires less nutes. (Or, rather, can tolerate less nutes before it shows signs of nute burn.) This is one reason why I suggest just feeding until your plants seem "happy" and just showing the slightest bit of burn...then backing off a little bit. It's hard to tell, because different plants vary so much! Also, remember that in coco you're just "changing" the levels (unless you do a flush with at least 3 - 4x times the volume of your medium + a chelate, then the same with plain water, then nutrients again, etc, etc...) In other words, you're never truly flushing coco, just changing the nute balance. (And that varies based on how much water and how much of each nutrient each plant takes up.) The plant I feed at 1400µs has runoff that edges up to 2200µs, at which point it starts looking unhappy, then I alternate with plain water, which seems to work well (more-so than just using a weaker solution.) The other two, I'm actually constantly feeding at 2100µs, and the runoff tends to be around 1800µs for both! (So they use up more nutes than water, and the ratio seems to be quite good for those two...still flush them with a chelating agent weekly, though.) I'm really still learning myself, and the hard water just confounds things further...I should supposedly have water in the 20 - 50µs range when I move, or I'll install an RO system then, so that'll remove some of the variables.
Btw, when I went back and reread your post properly (hmm, perhaps some of what I vaped before wore off... ), I too wonder why your ec is off so much from the calculated numbers. It's quite possible that their calculator is just broken (and the first thing I'd do is email them and ask!) Make sure your numbers and unit conversions are correct too, since the growing world mixes imperial units with proper metric units far-too-often... ...and have you checked/calibrated your ec meter? I'd say the conversion factor might be off, but 2.6x expected ec isn't a conversion-factor issue... Then again, it's hard for an ec meter to get off by that much as well. It could also be that one of your ingredients is screwy (test them separately?)
When using the CNS17 line with the LK I noticed that the my EC(.5) climbs up considerably, but from what I've read nothing to worry about,as long as your profile ratios are in acceptable range.. FWIW I add the LK last it lowers the Ph some..
I've checked and double checked, all the correct units have been input. Everything is metric except for the res size which is in gallons. I did calibrate my meter before doing any tests just to make sure that everything was set up correctly. As for the liquid karma, it does the same thing, when I put 10mL into a gallon of solution, the EC raises .35 and it is only contribution 15ppm of active elements. Cheecha, do you use the cns17 coco bloom? That stuff is really high in EC compared to the ripe. The ripe at 25 ml, like botanicare calls for, is 578 ppm active elements and an EC of 1.46, while 25 ml of bloom has only 631 ppm of active elements but an EC of 3.1.
In coco with the cns17 line I usually feed at ~800-<1000max ppm(.5 scale), and water topoffs to 1/2 strength feeds, then full strength and so on..I typically incorporate ripe at around 3-4 wks with 15ml Blm and 5ml ripe,some epsom salt and 2-3ml protekt.. Last couple wks start dropping the blm and only lower levels of ripe till flush..Flush for me is whatever gets me to my original tap level(s) ~120-140ppm..Works for me and my girls.. YMMV of course..
When I work out that formula in my spreadsheet, it comes to 1100ppm @ .5 but only 564 ppm of active elements. The ppm is a touch higher than you say you are feeding, but is still not that far off. According to my spreadsheet, that is a pretty good profile; 92-63-162-116-26 (n-p-k-ca-mg)
Actually Mg is closer to ~50ppm with the added epsom salt..so pretty close to 2:1 Ca:Mg I'm finding out that following the correct ratios and not so much what the EC meter tells me, is what counts..IMO..That and reading the plants of course.. Cheers!..
With the CNS17 bloom& Ripe line having such a low %, yes about a gram/gal=~26ppmMg 34S... With other products and depending on their %, I usually add between 1/4-1gr of ES..