Maybe I should explain my situation better. As it seems there are some other variables I left out. I grow in coco and feed with synthetic nutes. I have a sump set up to catch all of the runoff from the plants. It pumps out every few days to waste. If I think I’m having a salt buildup. I’ll drop my EC meter in the sump to check the strength of the runoff. As I catch all of my runoff, it should give a reasonably accurate measurement of the total ppm in the runoff. It is usually within 100ppm of my input feed. So if I check and it’s a few hundred or more over my input, it’s flushing time. I don’t usually run into this problem though. I give my girls a weekly AACT flush by hand with Recharge microbes, molasses, and some kelp. I also auto feed multiple times a day. I hardly ever have a salt buildup issue.