Originally Posted by jidoka
In practice I can get about 3-3.5 g/gal gypsum through the micro sprinklers. If I could do more I would
It would really help the quality of your post if you would distinguish what you are discussing a bit more. Are all your recent comments referring to this Denver consulting biz you have on coco?
This thread really isn't about producing in Coco. It is about growing in soil.
As you are seeing in Coco, you are doing hydroponics. And as you can see, the big issue is how do you get enough Ca into hydroponics? The worlds foregone conclusion about hyroponics is that you can't.
Lots of folks were using dolomite to season their coco. Probably not a bad idea.
Is this drain to waste or recirculated?
A good Israeli friend of mine who is recently retired, used to produce hydroponic peppers and tomatoes. We have had this conversation many times on how to get Ca uptake in hydroponics, so this is not the first time this problem has been visited.
One method was to use gypsum rocks and a bit of fines along with calcium carbonate rock and a bit of fines and mix it into the mix of medium. The second would be to run good Ca chelates without synthetic N.
If I were in an established place like you are talking and I was draining to waste, I might think of top dressing with worm castings mixed with gypsum and maybe even a bit of calcium carbonate depending on pH of the water and what carbonate you have available.
I noted that you are trying to use Calcium nitrate. You are going to be pulling up way too much nitrate trying to get your Ca up high enough. There are a number of good chelates on the market that are based on amino acids. Some are pretty reasonable, obviously not the cost of nitrate either... but in this case, the cost is not really an issue if you can get the ppms of Ca up. Even with a lower analysis, a chelate may get better Calcium uptake than the nitrate form of Ca and not give you that super human growth either.