How long before first algae bloom

I'm at 6 weeks with my tank, but most my rock was from a 6 month old system, and I didnt kill it in the move, so my cycle went faster.

That said at the 6 week mark as we speak my tank is growing out massive amounts of yellow/brown diatoms. I siphoned off 8 gallons of my 56 and by the time I filled the tank back up, had dinner and went back in the sand was yellow again

 

As per suggestions

As per PharmrJohn suggestion -
I have reduced lighting to actinics and turned off the proteing skimmer.

I left the phosban reactor in service as I have always had a phosphate problem in every aquarium I have had. Determined to avoid it this time.

I had already done a 4 gallon water change prior to lunatik's suggestion not to - can't back out of that.

Installed a SeaChem Amonia Alert so I can do a quick look several times a day. It says my amonia is < .02ppm. Reducing feeding to three times a week.

The two fish I have are Spotted Cardinals - they are still alive and kicking.

The replies I received focused only on the rock. In addition to the 30lbs of CaribSea Aragamax sand, I also put in 60lbs of CaribSea Agrag-Alive sand (on top of the dry sand). Does this not expedite the propogation of the bacteria?

In wait and watch mode - probably for another six weeks.

Thanks to those who replied to my post - feedback is appreciated.

 

It's here

Algae bloom - Not brown, but green, and only on the rock.

Two little fishies still alive and well, amonia still < 0.2ppm. I changed my sock this AM and leveled the sand - Lots of sand drifts with MP40.