Bare in mind that heterotrophs are organisms that eat plants and animals for their energy, not wait for them to die. I believe flesh-eating bacteria would be classified as such. They don’t wait for their food to die but are predatory rather; eating at them as an open food source. I’d imagine that nutrient rich algae would be fair game and provide them with all they need. Products like vibrant need to be constantly added to keep their populations strong enough to make an impact on algae. I’d imagine that they don’t reproduce well in a reef tank where countless other bacterial strains also live. I’ve read quite a bit about vibrant and wanted understand more about it before adding it. It is much different than carbon dosing to bolster nitrifying bacteria to tackle nutrients to starve out algae.I suspect it works in a different way, most marine macroalgae are made of carbon, nitrogen, phosphorus, amino acids fatty acids and vitamins. In the event of any off the above being depleted from the water column the algae will start to die off and as that happens bacteria will start to break it down back to carbon, nitrogen, phosphorus, aminos, fatty acids and vitamins. Bacteria cultures will transform carbon, nitrogen and phosphorus and the protein skimmer will remove the rest. Bringing the balance back. This process can take sometime just a week to happen.