I've used and loved Neptune's harvest fish hydrolysate and Age Old Organics grow/bloom for a long time. I was also happy to find out those products tested below detectable limits for arsenic and cadmium in third party testing. I recommend looking up any product you're interested in before you buy, because of lot of the most popular liquid organic nutrients are loaded with heavy metals.
https://apps1.cdfa.ca.gov/fertilizerproducts/
This is a growing problem in agriculture, and not just our hobby. I just saw this today:
https://www.cnn.com/2021/02/04/health/baby-food-heavy-metal-toxins-wellness/index.html Allowing even a small amount of arsenic in cadmium allows it to accumulate over time to toxic levels-and note many of these brands are the most expensive organic brands of baby food...crazy!