Dismantle..... I was about to panic and then realised that you meant UPGRADE!!!!
Yes do it - more space = more corals also with double the volume you may be tempted by another fish or two! The bigger fuge is also a good thing - not only more nutrient export which is always a good thing but also more space for pods to grow to feed that mandarin.
Not sure about the 20k bulb though - all a question of taste. I found 10k too yellow, quite liked 12k, preferred 14k but found 20k too blue.
I've run a 10k, didn't like it, too yellow for a Marine tank. Sorry, I've got a 14k now, not a 12k, and I like it, but I've got a lot of zoas in this tank and I just really think they'll pop something serious with a 20k, I already have really nice color.
Yes, the 110 space is nearly double that of the 70's space, but a similar impeller design. Lots of room for pods, snails, starfish, lots of little beasties, tempted to add LR in that fuge, but I dunno... I've heard good and bad about putting the sand bed and the rock. Nitrate trap and it really should be a bigger fuge for this. Mines great for macro growth and nutrient export. Pods grow in the chaeto too, so I'm not complaining.
Oh, I'd never make you panic. The tank also has a far superior lid, no gaps and a hinge to open it partially. I'm a wee bit concerned that there may be a shadow over the darker part of the hinge, but I don't think it'll be much of a difference with the MH. Here's the hood for the ADA.
Right now the tank is a filterless ADA, running on two Koralia 425s, Plants are doing great, but I'm just not as into plants anymore. Love them, but I've been doing the same things with planted tanks for a while because I'm very limited in South Florida with equipment and such. It's more expensive to run a top notch planted tank in Miami with quality animals than to run a top notch Marine tank, kid you not, and I'd rather focus my hobby on tanks where I have good access to equipment and livestock. They are so behind the game with planted tanks in Miami. Haha, if I were in the UK, I'd totally be doing planted tanks rather than Marine.
As you can see, the tank has great dimensions. And the ADA glass will be stunning for a marine tank.
L