Not at all, in fact in both my grows now in FFOF with MC have been very successful. The MC is a very grower friendly product in my opinion and I have found it works well together when used at regular doseage. It's a dry product, smells funky, is very dusty, and may bring pH in check for hydro grows.
I start with MC about 4 weeks in on the WW photos and almost right away at a light dose with these PE autos I have going now. As hot as the FFOF is suppose to be it hasn't bothered either of the grows yet. The autos I got into the final 5gal right away at tap root into the FFOF.
For the most part I use rain water at pH of 6.5ish, and 10.5g of MC in 1gal of water drops it to about 5.8. With Calmag a little lower. I use a few flakes of caustic potash and it's easy to adjust.
You know with MC when you are getting close to over feeding by the darkening of the tips to a dark green. One thing they tell you is to watch the color of the plants. The N they add is enough so that when you feed too much the plant gets a darker green, and too little it turns a lighter green.
This is a pic I took tonight, and believe it or not it was done in MG Organic Potting soil which claims to have nutes in it for 3 months. Now contrary to popular belief, The MG to me works really well and did not time release any nutes whatsoever. No bugs and when mixed with MC for feeding you can see what happened! In fact the pot is loaded with MG Perlite and Sea Compost, 70soil/25compost/5 perlite. The point is MC is very consistent throughout two so-called hot soils and works well in both.
My apologies to
@playerunknown for posting pics in his journal but I thought it was relevant.