I'm very glad! Sometimes it takes days! Yours must be in excellent condition---
That nitrate is a bit high. Try to get that down. A water change would definitely help that matter. Corals don't like nitrate and they really, really don't like ammonia. Calcium reading is very good. Your alk is particularly important too; it's like an acid bath for them if that drops below 8.3. You can be as high as 11, but I prefer the middle of that range. Kent Super Buffer can raise alk. I use Kent Turbo Calcium for the calcium. If you ever find cal and alk won't stabilize, check magnesium. If your alk is about 8.3, that's pretty well what your ph will be, and that's a good reading.
Plates are reputed to be difficult. But if they're happy, they're happy.
Ever see 'Little Shop of Horrors'? I call mine Audrey, after the omnivorous plant.
I've found very little it won't eat...garlic-laced Formula One sinking pellets, fish poo, you name it. If it gets near the edge of the plate, it's plate-food. I love these corals.
Frequency: just remember what you put into your tank is IN your tank, even if it goes into something's belly, and don't overdo it. You still have bioload to consider. I save the really high protein hits for about once a week, and just let Audrey catch fish-pellets on most days.
She's grown from a flat, barren plate to something approximating a Pillsbury biscuit in a month and a half. Give your plate all the room it wants. Even with cyclopeeze she waves her tentacles about and gathers a fair collection of bits that go into the mouth.