Reef Safe Cement With Good Local Availability

[Enigma]

I need a reef safe cement that has good local availability.

I kind of randomly tossed some rock together, and came up with a scape that I love. I want to cement it all together before I move it.

Unfortunately, I built it in the downstairs bathroom: so close to the door that only two of us who live in house can even get the door open far enough to get into the bathroom.

What can I purchase here in Calgary, pronto, that is reef safe? I've read that Portland #3 is good, but I also think it might have limited availability. I'm not overly worried about silicates: I'm just worried about not killing anything.