carlosmendes

Hi All,

I have been doing a lot of research into different dosing strategies, including vast consultation with plant guru's in my area (Waterloo, Ontario, Canada). and I have a few questions/concerns.

First: Is that MgSO4 necessary if my GH is at 5 and KH at 8 .

Second: I am using hydroponics Trace #6 Chelate Trace element (Fe 7%, B 1.3%, Mn 2%, Zn 0.4%, Cu 0.1%, Mo 0.06%) but the calculator asks for 40g for a 500ml solution. that is a lot more than the one tablespoon (~15g) that the PMDD and many other variations I found on the web.

Can someone explain why so much more? or am I making a mistake in the comparison?

Thanks
Carlos

ray-the-pilot

Maybe not but you cannot tell. GH measures Ca and Mg. If your water is all Ca then you will have a Mg deficiency. You need to test your water for Mg to find out how much you have.
The amount of Mg you add using PPS is minuscule so not using it is not a good idea unless you actually know you have plenty of Mg.

You cannot make accurate comparisons between volume (tablespoons) and mass (grams) of different formulations. The density (g/tbs) is often not the same. That being said. a difference of 40g vs. 15g of a fertilizer is not that big! I doubt that if you reduce the Fe by 1/3 your plants will notice anything.