Welcome to Part 3 of my SW system guide, for this part, I will assume that Parts 1 and 2 have been read. Starting a SW System - Part 1 - Where to start (Research) Starting a SW System - Part 2 - Bringing Nature Home (Researching Equipment) Revision - what we've learnt so far Part 1 - Environment Research; The Reefs of the World, Reef Life, Deciding on a Setup Part 2 - Equipment Research; SW Chemistry, Testing Equipment, Filtration and Flow, Sumps, Lighting So now we know what setup we want, and a bit about the equipment and how it works. I didn't know whether the next step should be designing a system, or stocking. I figure since most are limited by space, that designing the system should come first, and based on the setup size etc, worry about stocking later. So where to start? Size of the Display Tank - the bigger the better in a SW environment. As we've learnt, the ocean is a very large place, and with most specimens hand caught, we want to provide the most natural environment possible, that means size. Most marine species are not suited to nano setups (sub 30G), so a setup of at least 30G is definitely recommended. Preferably 55G or more. Next, I would decide on a nutrient export method. We've learnt that nitrate and phosphate levels on a reef are very low (below 1ppm in some cases). We also know that, a by-product of the nitrogen cycle is nitrate. We need to choose how we want to control and reduce nitrates in our system. For this, we can choose from: *Lots of water changes *Nitrate and Phosphate Reactors - chemically removes nitrates and phosphates. *Refugium with Deep Sand Bed and Macro Algae - the macro algae feeds on nitrates and phosphates *Carbon dosing - a more advanced method whereby nitrates are broken down so that nitrate eating bacteria can feed on them. This method is also referred to as Vodka/Sugar/Vinegar dosing. A sump is recommended for Reactors and Refugium methods, and whilst carbon dosing can be accomplished by directly dosing the display, it is recommended to dose into a sump if available. *Note: Carbon dosing requires a very efficient protein skimmer. Lighting - is one of the easier aspects, choosing a system is up to the individual, so long as the said system is suitable for the intended setup (i.e. appropriate lighting for corals if keeping a reef) What about a water source for Salt Water? The marine aquarist has two choices when it comes to SW, and can be dictated by distance. Natural Salt Water - this is water taken straight from the ocean. It is usually sold by marine LFS. Artificial Salt Water - this is made by mixing marine salt mixes with water, usually RO/DI Water because of it's purity. Both options work fine, and it's up to the individual to decide which way to go.