Jenetik

I just bought a 90 dollar oakton TDS meter and I was wondering how I use this in conjunction with my setup. I put the meter in the water and it read "220 ppm" .. What does this mean? What should I try to be getting at..? What is TDS anyway? I'm using GH nutes and superthrive during my flowering stage right now.. Any help would be great!

Aerobuds

First of all, TDS is total dissolved solids. It is a very useful tool to have. It allows you dial in the exact amount of nutes you want to feed your plants. Different plants will react differently to the amount of nutes you give them. I keep my cloner at around 250ppm, But when I'm in the flowering stage I run them as high as 1500ppm. This doesn't mean you should go by the numbers I use. I have read people severly burning thier plants as only 900 ppm. You just have to experiment, Raise your PPM a little bit at a time until you start to see some fert burn on the leaves, Then just back off a little.

Hope this helps

Aerobuds

Jenetik

Wow, thanks.. helps a lot..

Is there anyway I can tell the N-P-K values with this? I am kind of confused what to use for flowering.. The FloraBloom I am using was 0-5-4.. I know you want to keep the water at 2-4-5 during the flowering stages, but I don't have any 2-4-5 nutrients, so I have been using 1/3 FloraGro (2-1-6), 1/3 FloraMicro (5-0-1) and 1/3 FloraBloom (0-5-4).. I also added about 6 or so drops of Superthrive (unknown NPK value on bottle).. Should I continue to use the Gro/Micro during the flowering stages? I quit using the Micro/Gro for about a week and had lots of yellowing leaves near the bottom of the plant (which is normal), but I recently got more yellowing leaves even towards the center of the plants, so I added some Micro/Gro in hopes of sprucing up the leaves a bit.. Any advice would be helpful

Aerobuds

I'm not real familiar with the nutes you are using but I'll try to help. The FloraGro is for your Veg stage, The FlorBloom is for the flowering stage and the FloraMicro is for your Micro Nutrients.
You should probably stop using the Floragro and use just The FloraBloom, Then add your FloraMicro once a week per the directions on the bottle. The FloraMicro should have enough Nitrogen to keep your plants from yellowing. But this is just IMO, Maybe somebody more familiar with the nutes you are using can help you more.

The Tds meter wont give specific measurement for each Nute, It just tells you how much solids are in your water.

Aerobuds

malibu

www.4oakton.com has the oakton manuals online -- the one that I found from a google search showed how the same "actual" ppm concentration of different salts (ions/nutes) will give different readings of conductivity -- and thus a different reading for the TDS (TDS is computed from EC -- all these meters actual measure the electrical conductivity of the aqueous solution - pure distilled water would be zero, tap water already has ions in it so it has some EC )
in general -- for the same mix of ions N-P-K , the more nutes = more EC

but even if you COULD get the actual ppm concentration total the same when changing to a different N-P-K mix, the different electrical characteristics alone would give you a different reading for EC (and the computed TDS) - makes this part trickier to interpret TDS for everyone!

yellowing lower leaves -- seem like they're telling you they are starving for nutes, if it is time for flowering I'd start adding in more bloom to the mix

I have been thinking of ordering a Hanna Agritest meter for myself, the oakton combo pH/TDS meters seem very expensive- I think you have to be sure you keep these in a storage solution to protect the pH electrode.
anyone have any experience with it?

OzGrowa

Hello folks,
I was doing a bit of reading here and I agree, a pen is essential to measure the nutrients within a hydroponic solution.

BUT we must always remember that a pen/wand is not measuring elemental specifics, such as the amount of Nitrogen used, or te amount of Pot***ium,etc we are getting a broad reading and this is often the problem with using the EC as the sole way to work out what is occuring.

Hanna has relead a mini m*** spec machine that will alow individual analyses of elemnts, these are still real expensive though. Its unfortunate that the costs are so high for this, as we can really bring out the best in our plants by supplementing and perhaps subracting elements at certain critical stages of the plants life.

PPM as a measurement scale can unfortunatley be unreliable as you are reliying on a conversion from EC to PPM ,from a chip. Different people have different pens so we get different conversion values, EC is generally used in preference over the ppm scale as its a standard that is universal and also is ANSI compliant.

In relation to nutrient strength and burn, its Ph relative, the more acidic the more protein donation and the more uptake, this is often when the burn occurs.

just some thoughts,
OzGrowa

Aerobuds

Hey OZ,

I have a fairly high end Hannah meter. It measure's both TDS and EC. Right now I don't use the EC reading because I found most people here are using the TDS reading. Do you think I should stop using the TDS and switch to using the EC reading instead.

Aerobuds

malibu

hi Aerobuds -
the lower end Hanna pen model I'm ordering comes in either EC or TDS versions, both with pH.

I decided to go with the EC model and multiply by the factor 0.7 the chip in the TDS model would use anyway to get the ppm number, and then be able to communicate with others.

supposedly EC will eventually be the international standard, but everyone understands ppm now.

St0ney

You need to use all 3 bottles in you GH nutes. Even in flowering you need to put in the grow/micro/bloom - the amounts you put in of each is how you adjust it. During flowering you need at LEAST 1/4 tsp of FloraGro, 1/2 tsp FloraMicro, 3/4 tsp FloraBloom PER GALLON.. from there you can adjust it as you need to for you plants by raising or lowering each part independently. Does that make since?

Anhways I know this is an old thread.. but I thought I would let you know..

St0ney
Staying High

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budjamesbud

ok
i got a hanna that reads ppm
if i want to convert to ec i divide by the converion factor right?
what is convewrsion factore for hanna? .7?
ec is more universal than ppm? because of diffs in conversion factors of diff pens?
is this right?

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