Thanks to @Why-Me looks like I’ll be going bare bottom now. I’ll be buying the Brs 24x24 1/8 black ABS plastic sheet to protect the bottom. I have two a Atos and I have both of them in the return pump section. I just re read through the instruction booklet and the only thing I could find was that its not supposed to be placed somewhere with micro bubbles because it may affect the sensor.I have the heater in the last chamber with the return pump. I went with an eheim heater and they're super long so with my tupperware of miracle mud in the fuge, that was the only spot for it really.
hmm idk, I think the XP Aqua ATO says something about not putting it in a section with the return pump? It seems like it's fine there, but I've been debating adding kalkwasser to my ATO and I'm not sure I'd want it dumping that water into my fuge with limited flow in there. I'm pondering the idea of removing the mud, moving heater to the fuge and just laying it on the bottom, then having the ATO in the return pump area along with dosing tubes which I'm apparently going to need soon now that I've got a few SPS corals going hard. I don't really see why the ATO couldn't be in the return pump area.
If you're going barebottom this isn't really an option, but I went with eggcrate on the bottom of my tank and then covered it with sand, iirc I read it makes the rockwork a little more stable and less likely to topple over. I wanted some wrasses so barebottom just wasn't an option. That said, if you want SPS, I totally get why people with those tanks go that route. I don't think I have super high flow in my tank, but the sand (fiji pink) does get blown around a bit and I'm rolling with: 1 tunze powehead ~450 gph, 1 sicce powerhead ~500 gph, icecap 1k at max of 40% so I guess ~400 gph, and then a simplicity return pump which is 1300 gph I think, but I run it at around half so ~650 gph. The bummer I've found is anything over that 500 gph area seems to blow sand around or feel like too much flow for the LPS.