Fulbay

Thanks for the link, very helpful. I talked to a family friend who's a builder and he reckons at least a 2 x 6 as well. As for the refugium, well many reasons. Firstly i think it's quite a novel idea, it would be a rather unique setup. Although the main reason is that i can't have a soil substrate in my top tank nor any plants because i have a turtle. He was how i got into the aquarium hobby. He would dig up all the soil and make a huge mess, plus whenever i put plants in his tank he just rips them up. Furthermore, it'll be a good hospital tank for turtle relates fish injuries (Very rare) and a good place for breeding. Lastly, it will heavily aid in filtration which is always a plus! I will be making the refugium myself and the justification for the 6mm glass thickness is that the three planned baffles will also act as fantastic braces for the tank, i imagine that there will be no bowing at all. The top doors will have a small vertical beam hanging down above the refugium where the doors will "clip into"using things like these

I'll be using thicker top lateral beams than the vertical ones. Do you think 2 x 4 would be sufficient? As for the above sump doors i'm thinking of putting a vertical beam halfway between them and putting plastic push latches in to keep the doors in place. Something like this:

Thanks so much for the input, The last baffle is 330 mm high so that leaves at least 80 mm of extra space for the extra water that drains down when the pump switches off. For the surface disturbance, apparently using a soil substrate releases dissolved organic carbon into the water as it is "broken down", well according to Diana Walstad. Also, i will be using emergent plants aswell so they will have unlimited access to co2. The stand is just a rough sketch, for the top lateral beams i'll be using thicker wood than the vertical beams.

Im getting the top tank made for me and the bottom tank is a 55 gal i already have, i'll just use acrylic for the baffle's. The quote is $340 and the guy seems to think 12mm is enough. I did a rimless tank safety calculator and with 12mm glass the safety factor is apparently 12.

Here is my intended freshwater setup. The top tank is 1800 mm x 400 mm h x 500 mm w. It will be made be made from 12mm glass and will be completely braceless. The bottom tank will be on display with access to the top and side of the sump/refugium through cabinet doors. Here is a detailed view of the sump/refugium. It will be 1200 mm x 450 mm h x 400 mm w and it will be made from 6mm glass. I will be using filter floss, bioballs and probably ceramic thingees in the direct filtration side on the left. it will then flow into the refugium, it will be well lit with 6500k cfl's and it will have a soil bottom with a gravel cap. The plants inside will be a huge variety I've collected. Some will be made to grow emmersed. It will then flow into the last chamber which will house the pump and heaters. Here is a rough mockup of my proposed stand. I'm coming to this fantastic board because i'm a fellow Aquarist from Auckland. I would love your input on this project and any criticisms. Thank you.