So maxima clams are collected in areas with 7.5dkh. they are filter feeders it’s best to keep your nutrients elevated. I’ve raise 2 clams from about 1.25”
I used to dose phytoplankton, but at this size they want light. Make sure they are not shaded.
Being a filter feeder doesn’t mean an organism wants higher nutrients (phosphates and nitrates).
Filter feeders want zooplankton in the water, and not necessarily nitrates and phosphates. Those are what photosynthetic organisms want.
People mistake this because in the home aquaria, feeding filter feeders results in higher nutrients, but that often kills the said organisms, which like lower nutrients despite requiring zooplankton in water.
Same can be said for clams which appreciate plankton in the water but don’t like too high nutrients.
In the ocean this is doable (low nutrient, high zooplankton) but hard in the aquarium