We used to use diluted bleach to clean ours. Did it for years with no problems. I use to let it sit over night and not put much bleach in the water. You will eventually know the least amount it takes.
I then let them soak in fresh water and periodically changing the water. Checking for a bleach smell is a definate must. Used to take 2-3 days to get everything back in the tank.
now, I won't have that issue
*180 gal Display, 100 gal basement sump, 33 gal refugium, 3x250 MH, 2x160 VHO actinics, zoos, some softies, LPS & lots of acros and other SPS.
*100 gal prop tank plumbed into main system w/ 2x96 PC lights and 1x150 MH,