To me, it makes far more sense to use a fertilizer known to contain all the essential elements in a ratio favorable to each other OR in a ratio that helps you manage the plant in a way that allows you to bend it to your will.

Let me explain it like this. Let's say that of the 12 essential nutrients plants take from the soil, fish emulsion has 6. We don't know the ratio, but let's put numbers on the nutrients and say it has elements 2,4,6,8,10, and 12 - just for the sake of this discussion. That means that in order for your plant to grow normally, you still need to add all the odd numbered elements, so you STILL need to fertilize. When you DO fertilize, the fertilizer is almost certain to contain some of the elements that were in the seaweed emulsion, so there will be duplication or an overlap of nutrients. The plant cannot USE the excess, and the excess unnecessarily contributes to the EC/TDS of your soil solution, which makes it more difficult for your plant to take up water and the nutrients dissolved in water.

Additionally, most of the nutrients in the SW emulsion are not soluble. They are locked in hydrocarbon chains and will only be accessible to the plant AFTER the hydrocarbon chains are cleaved and the nutrients broken down into elemental form. There is no way for us to determine when that might occur.

Using a soluble fertilizer that contains all the essential nutrients in a favorable ratio to each other on a regular basis, allows the plant IMMEDIATE access to the nutrients and helps you keep your EC/TDS levels at their lowest, w/o nutritional deficiencies. Keep in mind that an excess (toxicity) of any nutrient, and particularly of micro-nutrients can be as harmful as a deficiency, and the range between deficiency and toxicity in micronutrients is generally much smaller/narrower than it is in macronutrients.

As always, it's your call, but I use 1 soluble fertilizer on all almost all of my trees. The last two workshops I attended where I brought my own trees were given by Roy Nagatoshi and Marco Invernizzi. Both of these men, in their respective workshops, commented on the excellent health of my trees. I'm not mentioning that to be boastful, only to illustrate there are no magic bullets. A good soil and a simple, but effective nutritional supplementation program, along with sound watering habits, can go a long way toward helping you maintain your trees in consistent good vitality.

Not only has this approach worked extremely well for me in my bonsai pursuits, but I've also helped a large number (many hundreds) of people at the GW container forum implement a similar program, which by their own accounts has also proved very successful in that application.

Al

Here is a link that might be useful: Click me and I'll take you to more about nutrition