Ok. I used 200lbs of HD
Silica playsand as my dsb
(4.5 inches). Sand (silica dioxide) is what the glass is made of. All you have to do is rinse it really really well, which is a huge pain in the $@%. Mine has been going for almost 2 years, and I've not had any diatoms blooms, outside the small initial bloom when I got new PCs. I cured the tank with raw large shrimpt and about 150lbs of uncured live rock. It works fine. Only unwanted algae growth that I've had is the Cyano
that I've recently aqcuired in small amounts, which I attribute fully to my 5 month overdue RO
In short....I've had good success with the all dreaded SILICA playsand at $1.50/50lbs. Growing softies, tripled the size of open green brain, and grown many toadstool and leather frags
. I've had carpet anenome and gorgonians for over a year and they're great. The only key I would say is is to really really really rinse the heck out of it....you don't want any of the silica "bran" just the good stuff.
If anyone has had bad experiences I'd like to hear about them. As far as I know, not too many of you are dumb enough like me to try less than proven quality products on our precious systems.