IME use less of the EWC.So 40 % peat 20 EWC 40 perlite.You should be able to get some dry fertilizer,gypsum,rock dust from your garden store.Other things like alfalfa pellets from a farm feed store.
Whoever said guano is bad is 100% wrong. Whatever his problem was was due to a different additive...Guano is a plant superfood that is rich in the three essential plant nutrients, nitrogen, phosphorus, and potassium.