Diatoms

[Jstone]

So after having a fully cycled 29 gallon biocube tank for about 5-6 months, 2 clowns, yellow wrasse, cleaner shrimp, Devils hand. two ricordia mushrooms, RBTA, and hammer coral I started getting diatoms again, covering the sandbed. I began to manually remove them every time i would do a water change which I do 5 gallons every week. All water parameters always check out, with 0nitrate, 0phosphates, calcium 420, Alk-8. I only use RO water for top offs. I can't seem to figure out why I can't get control of this diatom bloom. I noticed the growth of sponges on the dark side of my LR so i may have excess nutrients. All of my corals and fish are very happy, and open. I have lost a Long tentacle plate, and blue chalice to the algae.

Should i be manually removing the algae or am i stirring it up too much?

[Ibuyen]

looks little like cyano. whats your flow like inside of the tank?

[Jstone]

flow is good throughout the tank. its something I've played around with and been very cognizent of. I do not believe it is cyano because it is not like a slime. but i could be wrong.

[Ibuyen]

you could turkey blaster it out, do you have snails, hermits, or something else that stirs up the sand?

[Jstone]

I manually pick it out during water changes, but not sure if i should be stirring up the sand. I imagine at this point all of the silicate is gone from the sand, but still not sure. and yes i have 5 snails, 2 nassarus snails, 8 hermit crabs, and 1 sea urchin.