Help! What are these white crystals?!

[TOMO2]

Can anyone help me ID these crystalline(?) deposits? They are allover my sump and some in my tank as well. Some are on the glass and come off easily with a scraper. Most are on plastic pieces like my return pump and algae scrapper and are hard to get off. My tank is 5 months old and I'm not dosing anything yet. I only have Nassarius and Bumble Bee snails but there are no snails in my sump. Relevant numbers are CA-325; Alk- 8.4 dKH; Ph- 8.4. My Nitrates and Nitrites were stable in acceptable ranges but now Nitrite has spiked to 4 while Nitrates has gone up to .2 (was hovering just over 0). Any help with ID and how to fix is greatly appreciated - Thanks in advance!

 

[Stang67]

They are a kind of worm. Pretty harmless will come and go.

 

[WalkerLovesTheOcean]

I see spirobid worms and something else that I am not sure what it is.

 

[TOMO2]

Got it! Thank you both for your help with this!