Lucas Formula: Add Back Calculator!

Smot360

Smot360

Well-Known Member
addback calculator - (for advanced users) (smot360- add back calculator1 )

say you were running the 0-8-16 formula, at 0.7 conversion with a 22 gallon res. When you first fill it up, your ppm will be around 1330.

Now you have been growing for a week, and some of the water has been taken up by the plants, some has evaporated, and now your res is at 947 ppm. You need to get your ppm from 947 to 1330. Here is the equation:

((target - current) / target) * 8 ml per gallon * res gallons = flora micro (ml) double this figure to get flora bloom (ml)

example:

((1330 - 947) / 1330) * 8 * 22
(383 / 1330) * 8 * 22
0.3 * 8 * 22 = 53 ml flora micro

53 ml flora micro, double that and you get 106 ml flora bloom. So 53 ml flora micro and 106 ml flora bloom to add back to your 22 gallon res to get you from 947 to 1330.


http://www.cannabis-world.org/cw/showthread.php?t=892
(smot360- add back calculator 2)
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thanks for the kind words friends

hello agent-smith

your figures are accurate, but im looking for something else

its involved with discount and markup math

the markup formula uses the target tds, and a current tds, to calculate the percentage difference, then use that percentage to multiply against the 8ml that produces the target

so if for example the target is 1300 and the current is 900 with a 50 gallon res it maths out like this

target/current-1*8*res size=how many ml of nutes to add to the res

1300/900-1*8*50=178 total ml of nutes to add to the res

phew, you forced me to remember that, thanks

this formula is much more accurate than a 33% addback. It is based on markup math, and produces a nute dosage that will tend to be slightly too much, the tds will be overshot

the inverse formula, using markdown math, produces a more conservative estimate

it goes like this
1-(current/target)*8*res size=total ml of nutes to add to res

what counts is to get enough nutes added back to get up to the target tds, of 1300-1400

the two formulas are predicting that to raise tds 400 points will take between 125 to 172ml of nutes

once you do it once, it will be the same the next time... You just need to get into the ballpark, or raise tds in steps..

Hth
lucas
Click to expand...
The "add back calculator 1" when you have a 50 gallon tank, and you are trying to reach a target ppm of 600 and your current ppm s are at 450 the calculations come out to say 100 ml of micro and 200 ml of bloom....

Now As you can see the "add back calculator 2" when you have a 50 gallon tank, and you are trying to reach a target ppm of 600 and your current ppm s are at 450 the calculations come out to say -250 ml of micro and -500 ml of bloom?? And then with a 30 gallon tank you are lookin at -90 ml of micro and -180 of bloom??? I do not understand these conversions....I was wondering if someone could help me out with this formula or maybe I am doing it wrong.

Which Formula/ Calculator is right! Can Anyone help me out PLEASE!
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If Anyone Wants to use these conversion methods quickly, I have Built and attached at the bottom; 2 Calculators Based on the above formulas

View attachment 1555754
View attachment 1555756
 
ExDex1x1

ExDex1x1

Active Member
using markdown math is the way to go. This will give you a low estimate of how much to add. Calculate, mix, adjust. Its always easier to add more than it is to try and dilute your concentration so go for a lowball number and work from there. Keep in mind this isn't precision math and experience with your individual nutrients will always be more effective than calculations. Do rough quick math and let your experience fill in the gaps.
 
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