PSA about over using Kelp.
Last year I ran into 2 farms who contacted me after failing for Arsenic after over using kelp extract for there potassium source. Both farms tested over the legal limit for heavy metals in tissue testing as in most states every 10 lbs of tissue must be tested as are all concentrates.
This year already I have been contacted by 3 different farms and its not even May. One of the farms was 4x the legal limit for Arsenic. This can’t just be a cannabis issue I am more than willing to bet alot of lettuce growers would test outside of the legal limits if we are seeing this kind of results in tissue samples in cannabis.
PLEASE be careful when suggesting kelp. It is safe to use when used reasonably but if you over dose it or think its going to solve your mystery plant deficiency or some one one told you that you only need kelp with iron and fish food please stop because this could become a much bigger issue for all of aquaponics if we don’t address this as a community quickly. So if your suggesting kelp as the best source of K for aquaponics please stop.
TLDR; Over dosing Kelp causes Arsenic accumulation only use it in small ammounts.