I have a 24g AP with 150w MH and I am having constant problems with the tank. I have a protein skimmer thats rated for tanks 25-75g, I go weekly 5-10 gal water changes, I dont overfeed, nothing is dead...but my nitrates are 80-100, and have been that way for months now. Someone told me that the rear chambers collect detritus and it sits and rots back there. No matter how hard I try, I cannot siphon it out. I went and bought a 26g bowfront (used) for $40 and will be transferring everything over to that tank in a few weeks. I love the look of the all in ones, but I wont get another one, and will sell this one once everyone is out. I still have the stock hood.
You could do something along those lines, buy a non-all in one tank, and set it up completely and it will cost around the same price as a 24g AP with 150w MH which is somewhere around $350 and that doesnt include a protein skimmer. You can get a tank for $40-60, the light $200 on ebay, skimmer $100, pumps $75, and if you want a fuge, $10 for a 10 gal tank = total around $450. A lot of that stuff you can get everything cheaper buying them from responsible reefers, or ebay. See if there's a local marine aquarists society around you, that's how I found my new tank. My new tank is already predrilled and painted. It also came with an overflow box, but I need to make a new one, as I broke it already (oops).
Just my thoughts, coming from someone who has had that exact tank since April, added my MH not even 2 months later.
