EC/TDS meters useless...?

Discussion in 'Growing Marijuana Indoors' started by Slypknow, Aug 19, 2006.

  1. Ok, so following guidelines I've read I went out and obtained an EC/TDS meter. I think I'm missing something with it, as what I've read people seem to live by these things.

    Example:
    Water out of the tap: 110ppm (not bad)

    I follow the directions on the charts for adding nutes and end up with 1500ppm. pH 6.3
    So I add some pH Down and now the TDS is 1600 (example again) with pH at 5.5.

    So now if I check it again after a couple days the pH has climbed to 6.3 again, water level has dropped and the TDS is around 1700....So I add more tap water to bring it back to original level, 5.5 pH and TDS is at 1600 again.

    My question is, how does this REALLY help me? How does this help you guys out there? I mean if you didnt buy one, followed the directions for your nutes and kept your resevoir water level the same...what is the TDS meter good for?


    Question #2: If I top off the water and end up with the same TDS I did when I started - are the plants NOT consuming nutes? If they were, wouldnt the TDS decline? I assumed people used these meters so that when they topped off their res they could also add more nutes to bring it back to the original count... mine just never seems to really go down. It's either higher (due to water evaporating, plants absorbing) or the same when I add water back into the rez....

    Please help me out as right now I'm thinking about putting this tool up on ebay and going without it. But I have a feeling I need it and it's extremely useful...I'm just missing it somewhere along the line.


    Thanks for any of you that can help!!
    -Slyp
     
  2. I believe it could come in handy if you're having a nute problem. If your PPM is too high at least you'll know it. Yet, I have no experience with a TDS meter.
     
  3. Hi KSAC - Thanks for taking the time to reply, however I am actually looking for someone who uses a TDS, knows what the numbers indicate, etc.

    I have a feeling this information could be seriously useful (perhaps a sticky) as I have NOT found one yet...and for the all the talking people do about how you NEED these things, it really makes a brutha wonder!
     
  4. I did find this tid-bit of info for ya. This is in relation to hydroponic growing

     
  5. Thanks KSAC... I had done research prior to asking these questions and what you just posted is about all I found.

    Here's the delimma:
    If I follow directions for the nutes, add lower pH and end up at 1500ppm. In 3 days, the water drops by about a gallon. I then take a fresh gallon of water, add pH down to reach my desired 5.5, and that single gallon of water is now at about 200ppm. I then add that gallon back into the tank.

    You would THINK that my overall ppm would be lower. Plants have fed on the nutes for 3 days right?

    Mine stays the same. Why?


    Most importantly, what use did the TDS give me? I mean if I followed the directions, ended up with 5ppm or 5000ppm... what's the benefit of knowing this?

    The only benefit I see is that during the 14 day period, a person can check the TDS daily and add nutes into the rez to bring the solution back to its original strength right? Plants are fed the same strength each day instead of nutes being slowly drained from the solution.

    Therein lies the issue.

    <crossing fingers that a master hydro-TDS user will reply>
     
  6. I think I can clear it up for you. A your nute level starts at 1500 - 3 days pass your tds is up, this should tell you that you are most likely giving her to much nutes, each plant is diff on how much nutes they are able to process. So in this case you need to reduce the tds level, on the other hand if your tds remains the same after 3 days and the water level is down then add when adding water add nutes as well. Last case if nutes are down then you need to increase your level when you add more water. That is what the tds meter is doing for you. Oh yeah, don't forget to dump your resevior every 10-14 days, unless you start having probs then reduce it to every 7 days. I personally change mine every 7 days.
     
  7. Ahhhh! Ok so if I'm correctly getting it things should go:


    Begin: 10gallons, 20ml of nutes per gallon, tds sitting at 1500 with pH at 5.5

    3 days pass - Scenarios

    Q: TDS IS ABOVE 1500 - STILL 10 GALLONS IN REZ (this hasn't happened, but possible)
    A: 20ml per gallon is too much, plants arent 'eating' enough. Lower to perhaps 19ml per gallon next rez change and watch

    Q: TDS IS ABOVE 1500 - REZ ONLY HAS 9 GALLONS (normal situation)
    A: DO NOT just add water (I have read this is what you are supposed to do as people say nutes do not evaporate, only water does), instead add 1 gallon WITH 20ml of nutes.

    Q: TDS IS BELOW 1500
    A: Regardless of water level this is bad. Indicates I am not putting enough nutes in to begin with and need to up the anti.

    I know you recommend to change the water every 7 days, which in some cases I do. The issue is more being anal with wanting to make sure the plants are getting as much nute as they need each day. It never made sense to me in that if I start with 20ml per gallon on Monday...then next Monday, chances are good there might only be 5ml per gallon, meaning the plants are starving by the time I change the rez.
     

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