In the past I’ve used 90% grade phosphoric mixed with 6 to 7parts water. This works really well except a 20 litre drum has gone from $90 to $400. $1000 to fill a 1000 litre pod…. Too expensive for me now. I’ve also done the electrolysis method using a large steel plate and baking soda in solution and a battery charger. Keen to hear any other cost efficient immersion methods. I just spoke to the local produce store and can get molasses for $120 for a 100 litre which will make 1000 litres…. But I’ve heard it gets on the nose… I think this will be the direction I go for the moment.