Nick

Yes but you can have a large sump for that inside a stand and still get 300L 1) You get the water volume this way 2) lighting is half the price as the surface area is smaller 3) Sump for large skimmer Having a huge display tank is all good but eventually it is going to cost money if you want to or not. More power heads, more salt, more lighting, more rodi, more coral, more fish, more sand, more rock etc My recommendation is based on being on a budget, if large budget then biggest you can fit/afford. Im going to do a 2nd tank once my corals are large enough to be fraged and will do this as its cheap.

To be honest I would just sell the old tank and get a smaller one. Too much work and cost for 450L A tank like these are cheap to run and stock. http://www.livingreefs.com/d2minis-real-130g-rimless-cube-build-thread-t22481p130.html http://www.flickr.com/photos/jgi27/3737615367/in/photostream/ Remember marine fish are expensive and its far cheaper to fill a small tank with coral and fish than 430L. 430L will look empty, you will need to spend $2k on fish/coral to make it look as good a one of these with $200 of coral and a say 3 fish. Reef lighting is way cheaper on a small tank. Use this to light it http://www.rapidled.com/servlet/the-PAR-Bulbs/Categories I have a 350L tank so speaking from experience.

If it were me and wanted to buy it I would do this. Build a new tank Buy good live rock No sandbed Use the lights, filter etc Move corals over Sell the tank and cabinet to help pay for the new tank

I would use the 200L tank as a sump Buy/build a 500mm cube Buy a PAR bulb (RapidLED.com) Buy live rock off someone on the forum so you dont have to wait months (put most in sump) Take the water to the local fish shop to test, once no nitrates, ammonia, nitrates buy 2 clown fish. Dont waste money on test kits yet. No substrate to start with (cheaper, easier to clean and you can add this later) Buy micron filter sock to polish water, they are reusable and very cheap (about $10) Buy a skimmer of TradeMe Buy heater off trademe Use Natural Sea Water to start with x1 power head for display tank x1 return pump from sump About 3m of tube Bulk head fittings in/out Mitre 10 - 20L water storage drums x2 for collecting water PVC pipe for in/out overflow etc Buy RODI/Salt later when you are over going to the sea every 2 weeks You can build a cost effective system this way. After a few months then get corals. The most expensive part will be the display tank with bulkhead fittings, pvc etc. The next big cost is RODI later on, if you go that direction. Also put a glass lid on the sump to help reduce evaporation. Also I would buy RODI water off someone and put in a 10L and drip feed it into sump to offset the evaporation. Cheaper to buy RODI water than an actual RODI system. My thoughts anyway.

I would put a hang on overflowbox with a line running down to a sump. Then get a pump to pump the water back up. Im doing that on a tank im building soon rather than drilling.

Keen to see some photos of that.