Initially, FoxFarm potting soil has an electrical conductivity (EC) range around 0.6-0.8, but as it starts to break down, this can rise to 1.8-2.1 mS/cm depending on many factors, as it's a nutrient-dense and packed with organic matter.
Organic matter that which is waiting to be broken down into smaller sizes for uptake.
The best thing you can do when you're playing with organics is to grab an EC metre for your soil (not a TDS for run off). Electrical conductivity requires two things, salts and water, so if it's low, you know it's time to water. EC doesn't measure "organic matter" it measures the capacity of salt ions "capable" of uptake by the plant at that time. If you test again after you water, and it's still low, then you know it's safe to add more immediately available salt mineral nutrients. You need to keep tabs to know when it's time to flush that nitrogen out and prevent EC/nitrogen ratio from getting to eventual toxic levels or its going to skew ph, it's not a if but when, by the time that blood meal starts breaking down, it's going to be 2-3rd week in flower(if auto), at a time when the plant needs less and less nitrogen, your microorganisms are going to be releasing nitrogen into the soil all throughout flower, as the plant uses less and less nitrogen due to its stage of growth, This will eventually skew ratio and acidify your medium, As ph geets lower and lower the conversion of nitrogen slows down but as soon as you ph back up its just going to crank back up nitrification of nitrogen. Keep an eye on your ph. If your plant can't use nutrients faster than they are being released the EC rises, if it rises above 1.8ms/cm the plant will start to stress with yellow tips, leech her back down (make space for more salts).
Keep the EC in range, whatever you feed to supplement, try not to add any more nitrogen.