added base rock, another diatom bloom?

[DonC]

I cycled my tank 40b with only 15 pounds of base rock and 7 pounds of live. It cylcled quickly and went through the brown diatom stage pretty fast as well. three days ago I added another 6 pound base rock. (dry) I soaked it , and rinsed it before adding it. I guess I should have gotten it all at once but money WAS an object ! lol. So, do you all think the new diatom (slight) bloom is from the new base rock bringing silica into the tank ? or is it not unheard of for a second bloom ? ro/di water by the way. I still have alittle GHA left over from that stage as well. My tank is about 5 weeks old and it was cycled at about 10 days.