Bloom boosters dtw?

Renfro

Well-Known Member
Ok, so those numbers are based on a formula, based on the elements they contain and not actual ppms? Why would they differ? Thanks
Read the link in my signature to understand the PPM. A PPM meter is just measuring electrical conductivity. Different substances conduct electricity at a different rate so you are really just getting a ballpark figure from the meter. Elemental PPM is more exacting and it tells you how much of what is in your mix.
 

The Gram Reaper

Well-Known Member
Read the link in my signature to understand the PPM. A PPM meter is just measuring electrical conductivity. Different substances conduct electricity at a different rate so you are really just getting a ballpark figure from the meter. Elemental PPM is more exacting and it tells you how much of what is in your mix.
That is very useful thanks. So, does a TDS meter measure ppm accurately? I thought TDS was PPM.

RAW Solubles has a quick guide for their PPM.
https://npk-industries.com/PPM_Values_of_RAW_products_in_1_Gallon_of_water.html
 

NeWcS

Well-Known Member
@Renfro But when we as growers talk PPM we are talking about what our meter is telling us, right? You tell me you have nute burn and the first thing I'd ask is how hot is your feed? ie; tell me what your meter reads.

I'll check your link..

Thanks man.
 

Renfro

Well-Known Member
@Renfro But when we as growers talk PPM we are talking about what our meter is telling us, right? You tell me you have nute burn and the first thing I'd ask is how hot is your feed? ie; tell me what your meter reads.
Yes, that is correct. Thats our easiest benchmark however inaccurate. Ever notice that for example adding GH Micro gives a much higher EC reading than it's true elemental PPM due to it's high metal content? But considering that most growers are pretty stable on the micro nutrients the main changes we are quantifying are additions and subtractions of the macro nutrients (NPK), calcium, magnesium so the EC method works well for us so long as the conversion rates are apples and apples.
 

Renfro

Well-Known Member
Great example. So the pen can't compensate for the variables. Gotcha. Thanks for taking time to explain.
No problem.

The GH Micro for example, when I add 1mL to a gallon I get a PPM meter reading showing about a 60 PPM change. When you calculate the elemental PPM taking specific gravity into account you get 35.36 PPM, much lower than the reading the meter gives.

The GH Bloom on the other hand, when I add 1 mL to a gallon I see about a 24.4 PPM change. The elemental number comes out to 24.3 PPM.
 
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