This is a little off topic.
But I find small foods work best with Echinata and Acans. They can take larger pieces but not as productively as smaller. I think larger items like brine shrimp size uses more energy to eat and digest. It takes more energy to close the polyps up and digest the larger food items, so it takes a greater bite out of the energy budget to process the food. Smaller food items like detritus that are nutrient packed can absorb through the tissue more easily allowing a smaller energy consumption to processing the foods. Smaller foods allow almost constant feeding as the polyp are not closed for business while processing the large food item towards the mouth and excreting the mesenterial filaments to start with digestion. So it wastes less energy possessing smaller foods and allows for almost constant feeding because the polyps can stay open longer. This allows for more energy to be gathered and redistributed to other things like calcification or sexual breeding and not towards metabolic needs. Efficient and increased feeding can stimulate calcification via enhanced bicarbonate production and the bicarbonate then can be used as a base for greater calcification rates. I blow my detritus up from around the rock and substrate edges a few times a week to feed my corals and it works like a charm.
One thing I learned over the years to increase my coral growth rates is simple. It all comes down to keeping the energy used to process the food as low as possible, keep food items the appropriate size for efficient feeding thus increasing the time the polyps are out and actively feeding and feed foods that are nutrient rich. If you stick to this formula for feeding and keep your building blocks like light, water flow, calcium, mag and alk at proper levels people will see a huge increase in growth rates and color.