why do we need a tdc and a ec meter

[Mor3no420]

i understand why we need a ph meter and know how to use but im not sure about the other two and what do they measure

 

[umbra]

TDS is total dissolved salts
EC is electrical conductivity

basically both are a measurement of the amount of nutrients that are dissolved in the water. EC is basically a measurement of resistance of the water. Take an ohm meter and measure the electrical resistance. The lower the number the less nutrients. Hydros run anywhere between 1.2 and 1.8 EC for rapid veg growth.

 

[andy52]

actually you don't.i rarely use my tds meter.after you get the hang of the strain you are growing,you just know how much nutes to add.to me the tds meter is not a necessity.but the ph meter is a must have.i grow in dwc and the only time i use my tds meter is to check when i change my res's out weekly.never in-between.you get a feel for what the plants need and go accordingly.thats just me.maybe others do it differently.but the ph,i want my solution dead on with the ph.no skimping on that

 

[smokingjoe]

I only ever test my res when I change out the solution weekly.

I've never had a ph meter, only ever used the aquarium style solution test kit.

I reckon I should shout myself a PH meter one of these days.

 

[Growdude]

I use mine often, for checking strength of nutes for small plants and when mixing up fresh nutes in my rez.
I use it in conjuntion with my PH probe to see if plants are being over/under feed.

I sure with exp. one would not have to use it but its going to help new growers most.

 

[andy52]

i agree with growdude.i would not start my dwc until my tds meter arrived.i am not saying its not important,it is.but using the GH nutes,i go by the directions on the bottle mostly.at least it gives me a range where i want to be at.when i start my little ones,i use 1/2 tsp per gallon of water and its usually around 200-300 tds.so the rest of the time that i start new plants,without checking the tds,i know what its going to be,so why check.i do check the tds when i change out,just to see how much the plants are taking up.what i'm trying to say is,if i had only 1 choice between a tds or a ph meter,i would go with the ph every time.my blue lab meter reads all,so not really an issue.i did order a ph meter just to have one on hand if something should happen to my bluelab.thanks all

 

[CasualGrower]

PH is a pretty important measurement to keep track of... One could get by without a TDS meter if you are gonna do regular water changes and follow preset formulas. However there are some people that rarely change their rez.... and then a TDS meter and a PH meter is definitely needed....

One of these growers that do not or did not anyway do regular changes is PuffinAFatty.... He would check is rez daily, Top off the water, check the PH and check the EC of his solution to keep it within range..... I beleive the only time he would do a full change is when starting a reveg or if problems would arise....... I might be wrong about this, but this is how I read his journal...... I think the last reveg though he was doing regular water changes....

 

[andy52]

you are right,thats the main reason i went with the lucas formula.he used it for yrs. i believe hes still using the GH line of nutes.hes been doing this for many,many yrs and is a great man to follow.thats what i told him,if its good enough for him,its dang sure good enough for me.the Gh nutes i'm talking about.

 

[Mor3no420]

so where is the tdc numbers need to be?
heres another thread i need help on
http://www.marijuanapassion.com/forum/showthread.php?p=376851#post376851

 

[andy52]

you need to go by the recommended dosage on the label,except cut it in half.to start i have a tds of 200-300.then as they get a better root system,i bump them up accordingly.