Hi! Congratulations!!! I've been successfully been running a 20G mixed reef without a sump or skimmer. I think a 40G is about as big as I'd go with a closed system like that, and you are right, regular maintenance and strict
water changes are key to success here. Another HUGE key to success is using a RODI system that produces 0
TDS water. RODI systems also must be maintained in good working order, though maintenance on that is much less frequent than the tank.
I also use an Aquaclear. It's an AC70 that's been modified slightly so it can handle mechanical, biological, and chemical filtration, and also work as a refugium, (fuge.) A fuge is simply a place where macroalgae, (usually chaeto), can be grown, and as it grows, it 'eats'
nitrates. So, like a skimmer but simpler, a fuge is for nutrient reduction. We wanted the space of an AC70, but when we turned it into a fuge by installing a couple of baffles, we also wanted to slow the flow through the
hob to water would have more contact time with everything inside... which includes a filter pad,
Seachem Matrix, quality carbon, and the chaeto. So, we switched out the AC70 impeller with one made for an AC30. If you'd like to see how this filter is set up, I'm pretty sure pics are on page 16 of my salty thread, which you can find linked in my signature.
With twice the volume, I'd either do two AC70's (one as a full fuge, the other for mechanical, bio, and chemI media) or an AC110. I think I'd prefer two 70's because I don't think the impeller can be switched on the 110, which I think is best for a fuge.
Whelp, I started writing this over an hour ago but got busy, so came back to finish and saw that good ol' Culprit is helping you out too. He's steering you right regarding
sand and rocks, though I'd just like to say,
live rock can be really great for cycling and biodiversity, but like anything, it has it's bad side too... and that is, it can come with pests and algae that you may not want to deal with. I decided dry rock was a better choice for me. It does take longer to cycle and become mature, biodiverse live rock, but it is guaranteed pest free and becomes live rock in the tank.
Yes, lighting is expensive and not something to take lightly if a reef tank is your goal. I started with T5's and while they were okay, it didn't work out for me in the long run. Good bulbs for a T5 fixture are ATI's or Geisemanns, which you can find online. However, good bulbs aren't all that cheap either, and with the cost of my fixture and the bulbs, I spent more than $200 on a light that, in the end, didn't fit well over my tank, so needed replacing. I then purchased an SB Reef Lights Ultra 22", which provides plenty of power for a 40B and is a very good light... though the app used to control it could be better. Anyhow, my point in sharing all of this is that I believe my biggest mistake was purchasing that first light and trying to make it work, only to have to invest in lighting a second time less than a year in. Do your research, and get the best light your budget will allow the first time around. Don't buy lighting twice.
Yes, you can transfer the rock and water in a Rubbermaid tote. It's important to keep live rock wet at all times, or you risk die off and an
ammonia spike/cycle issues.