So you recommend straight CC? I thought Oolite will get heavy eventually after it gets "settled" in if that isn't the case thanks for the heads up!
I don't know what to recommend since you know your end goals
and will be researching your livestock and making the tank to suite those goals.
I just know fine sand and SPS turn over rates, and fine sand and siphoning
just don't get it. When blending substrates, it will blend and mix up.
The sand will settle yes, but the two will mix it up also with a good portion
of sand available to get picked up by the PHs and scattered about.
Immagine siphoning the substrate, the sand will suck up 1st and higher
in the siphon, the detritus is similar and will be removed with the sand, then the heavier particles will drop back down.
Then lighter stuff will settle back down
as you try not to siphon too much fine sand, depositing the similar detritus
back on top of the CC. PHs will scatter what they will, and settlement will begin to recur. In the meantime,
since detritus and fine sand are similar, detritus should begin to gain popularity in the mix. If you do not siphon the sand
it will congeal, solidifying like concrete with detritus. Been there done that one.
I personally like the Special Grade CaribSea Arag Alive, but there's many options.
If you like burrowing fish and stars, research that for your substrate
then consider your reef above and see if this is a good match or not.
Best to research the system as a whole 1st before the initial buy for
substrate and water turnover rates.
I'm not sure a sand sifting star would do any good with large particles.
I would start a thread if I were you about sand particle size and
the goals of your tank including equipment and maintenance
"Sand size vs Flow Rate" or "Sand size and SPS coral and Burrowers"
I would like to see G's ideas on this.