FFOF and Salt Build Up?

Trying to find some information on how this works but no luck so far. I've heard here and there that FFOF has salt build up issues but I'm not exactly sure what this means. Can anyone elaborate on how and why this happens? I've seen white build up on the holes at the bottom of my buckets and I think its safe to assume thats the salt people are talking about. The cure is just a flush right? Any thing else to consider? Thanks.

Salt buildup is common in any medium. We can counteract the buildup by watering with plain water when we find the ppms of runoff to be higher than that of the ppms going into the medium. I think people mention that FFOF is a hot soil so you should generally take it easy on the nutrients and not use any until 4 or so weeks.

I would recommend keeping it easy on the nutrient mixes, start off at about 1/3 of recommended dose and remember to leech (feed only water) every second or third feeding.

What is the build up caused by?

SchweeDubz said:

What is the build up caused by?

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Nutrients that are left in the substrate. People usually counteract it by watering with just plain distilled or ro water until you get about 15-20% runoff every couple feedings. What I do is feed, water, feed, water and I've never had any salt buildup (well not enough to cause any issues at least).

Improper drainage, letting coco/rockwool dry out will cause ppm spikes and salt buildup, or no runoff. But mostly just feeding a high ppm and not leeching at all will usually end up with salt buildup.

Coco can be treated a bit differently though, you can feed a high ppm with little to no runoff and no leeching required if you keep the medium wet and not dry out at all.