hello
it seems it is a faily common anemone in the trade, I would say it is Heteractis sp. H.malu posseses short, plump tentacules, white with a more colorful tip whereas H.crispa has longer tentacules. There is also a point about the density of tentacules on the disk, which would have me say it is more a H.crispa.
Anyhow the tentacules are smooth so it excludes Phymanthus sp. and H.aurora as well
These two species may be white without impending the survival of the animal.
If they behave as corals do, even though they are hermatypic ( relying on the zooxantellate hosts for a part of their energy resources) they do absorb a lot of other things from the outside non living : sediments, paricules,disolved elements, feces, corpes of small animals, but also living from the bacteria to the bigger small fishes and crustacean animals.
So do not worry too much, if you don't see your anemone shrink, it certainly means it has found some kind of food source in your tank and lives on it. The signs of troubles would be a shrinking anemon, always moving for example. Which does not appear to be your case.
try from time to time some other kind of food and observe.
good luck
By the way, protect your pumps and sump. and these two species may be big.....
nano 240 lite