phosphate and adding dry rock

[Reef Pilot]

When I added a 2nd tank, I bought a bunch of marco dry rock and aged it for about 2 months, rinsing occasionally. I then added it to my tanks mixing 50/50 with my live rock. I did not see a phosphate spike. I was actually in progress with lowering my phosphates with GFO just before then, and it just continued until I reached zero a few months later.

So I don't think the new marco rock came with a lot of phosphates, or my aging and rinsing really helped. And it didn't take long for it to fit it (was white at first) and get covered with coralline algae.

I have read a lot on Canreef, how much people are against using dry rock. I don't really understand that, especially if it mixed with a good portion of live rock and sand.

My biggest fear at this point with my tanks is bringing in some bad pests (like flatworms). Dry rock certainly alleviates that concern.