The Sump & Refugium in the Saltwater Aquaria
Okie dokie so it's a little later than I wanted to post this (I worked 30 hours in two days over the weekend and the assignment took a little longer than I wanted on Friday) but here goes, I hope you enjoy this and find it useful/helpful Di and that everyone else enjoys it as well
I've done a general overview of it all for everyone to read and enjoy but I've also tried to directly relate it to your new addition at the same time Di
The Sump:
The sump is one of the most useful additions that a saltwater aquarium can receive, it's the unseen workhorse of our wonderful tanks. Possibly the greatest thing abut adding a sump to your aquarium is the additional water quantity it adds to the tank which allows for more stable parameters as there is a larger volume of water to dilute/diffuse any pollutants and it also slows any negative changes as more water takes longer to be affected. Which for a hobby where water quality is everything this is one of the best things your tank can have.
The next best thing about a sump is the ability to hide all of the equipment and filter media and such away and keep a much cleaning look in your DT (not that this is really a problem for the 250
) but it will also allow some more breathing room for what you use as filter media and other little sort of additions and subtractions that can be trialled out within the sump without worrying about how it will look. Having a sump also helps with maintenance as all equipment is in one place and it is not required for a treasure hunt to be undertaken to find something that might need checking. It also makes everything a little more accessible too (which I imagine would help greatly)
While the sump section isn't too long the other major help with the additions of a sump for you will be the increased allowance for your skimmer! The bigger the better and the nutrient removal from the water will be even better.
You may notice an increase in evap on the tank do to more water movement and longer times where the tank water is exposed to the air but this is also a benefit in disguise as more oxygen will be present in the water and your inhabitants will love that!
I personally don't have an enclosed cabinet for which my sump lies within but I also don't notice any extra moisture or dampness around it, I certainly don't think an anti-moisture coat would hurt at all! Adding a fan could also work but see what others say and I get the feeling you won't need to worry from what others have said
Now the fun bit
The Saltwater Aquaria Refugium:
One fantastic addition I think that every reef tank should have is a refugium, the benefits are too strong for there to be any reason not to have one. It may add the tiniest bit of extra care and maintenance to the tank, but hey! We're keeping reef tanks, what's a few extra minutes spent looking after our beautiful obsessions
There are a few different aspects that go into a refugium; the sort of inhabitants that you can add to help with water purification and add a food source, macro-algae's and the different types, DSB vs. SSB and the lighting and flow variables.
Lighting & Flow:
The main concept of the refugium in our tanks is for increased nutrient export and the removal of other unwanted waste products from our tanks. For this reason the large proportions of refugiums have a reduced flow, almost a trickle through the refugium area. This is to allow the macro-algae's and any other creatures or things the largest amount of time to be able to absorb this nutrient and waste while it spends time swirling around them before moving on. This can sometimes mean that there is a little bit of cyano or other unwanted algae but this, like our tanks, passes with time as the macro-algae grows and absorbs more nutrients. The flow is also good as it helps encourage growth of little critters like pods within the bounds of the fuge.
The lighting in a refugium, while not as complex as our tank lighting, is still very necessary. A fuge does not need a huge amount of light or ned to be some massive whizz-bang setup with all the bells and whistles. At the end of the day, all they needs is a fluorescent tube, power compact or a small led setup for the algae to have enough light to grow. If you have the opportunity to be able to put a bit more thought into the colours that get used within the fuge then, unlike the DT, you want light towards the red end of the spectrum as this is the best spectrum of light for algal growth. Sometimes people even use FW fluoro tubes for planted aquaria as they have a much redder colour but a simple flouro will be just fine, as will just about any other lighting. The only time you really need to think seriously about the lighting is if you have things like clams or some active filter feeding corals in your fuge. The other big aspect with lighting your fuge is when. I'd say the best thing to do is run an opposing cycle to your DT as this will greatly increase the stability of your pH levels and their fluctuations overnight. The reason behind this is, once the lights go out in your tank all the algae's and corals present in the tank will stop photosynthesising meaning that the CO[SUB]2[/SUB] will rise and the fish are still breathing and exhaling CO[SUB]2[/SUB]. This leads to a drop in pH due to the way that the CO[SUB]2[/SUB] reacts with the hydroxide (OH[SUP]-[/SUP]) and hydrogen (H[SUP]+[/SUP]) ions that determine the pH of something. If you run the lights in your fuge on an opposite cycle it means that while the DT isn't photosynthesising the fuge is and reducing the CO[SUB]2[/SUB] levels and vise-versa when the DT lights are on and the fuge lights are off, which therefore means that the pH levels throughout the day and night are much more stably with far less swing. I hope that chemistry lesson made sense!
DSB vs SSB:
The deep sand bed (DSB) vs the shallow sand bed (SSB) is something that gets a lot of discussion and neither side really ever wins so I'm not going to necessarily take a side but explain both in terms of pro's and con's.
The deep sand bed, 3-5 inches of sand, is very good for nutrient export and adding a heap of extra bacteria to your system that are able to further keep your bioload under control. The reason behind this is because the sand bed is so deep that it creates an anaerobic (lacking oxygen) environment and therefore allows anaerobic bacteria to grow and cultivate. This is another good form of bacteria for your tank and one that is usually quite lacking in a tank as there are not many locations for anaerobic bacteria to grow within a tank that doesn't have any deep sand beds, aside from deep within your LR. This is not necessary a bad thing as all the other bacteria's are perfectly capable of keeping up but who would say no to an extra good nutrient removal system? These bacteria are anther reason for reduced flows in your tank as the longer the water is in the fuge the more time it has to penetrate the sand bed and for the bacteria to be able to get at it to convert the nutrients. There are some serious con's with the DSB but they can be easily avoided with the correct level care. The most important thing to remember with a DSB is the shear amount of nutrients that can collect within in it. In some cases enough to be able to nuke a tank. This is simple to avoid by not disturbing the sand bed. Like when cleaning the fuge out and such, if you are going to be cleaning the sand only put the siphon down, no more than, an inch into the sand, as beyond that is where the anaerobic bacteria starts to begin. Some people recommend not even touching the sand but depending on how it looks and the rate of detritus settlement I think it may be necessary occasionally. It also means if you are moving the tank that you will need to discard it completely and start again to ensure the nutrients are not released into the tank. While this is a pretty big con, it is quite easy to avoid and ensure that a DSB works completely in your favour. Some people use mud/miracle mud in place or in conjunction with a DSB but I'm well versed with that setup so I'll let you pose the question to others if you wish to find out more
The shallow sand bed is pretty much just a standard sand bed like in any tank. It is 1-2.5 inches deep and doesn't come with the pro's or con's of a DSB. It will cultivate an amount of aerobic (oxygenated) bacteria within it's volume but nothing in comparison to the anaerobic of a DSB. The nutrient storage is also not present to anywhere near as much of an extent and therefore allows for cleaning and care without the hassles of releasing it. It also allows the addition of sand sifting animals like snails and stars to be used. The flow rate also isn't a variable either as there isn't the need to have nutrients settle.
If you were to ask my personal opinion or recommendation of one or the other I would be running a DSB as I find it fascinating, I really do love all life from the ammonia eating bacteria to my busy little angel to the polyps of my sps corals. I also think the benefits are worth the little bit extra care and attention that is required when running one.
Macro Algae:
These guys are pretty much the primary reason for the use of a refugium due to their significant abilities for nutrient removal from the water in your tank. There are many different types that you can add to your tank, all very beneficial, but I won't be writing up each one, rather just list a few really good choices and a few that you probably will want to avoid and the reasons why. While nutrient export is on everyone's mind when when macro-algae is mentioned the other unsung hero's of adding macro's are increased oxygen levels in the tank and more stable pH levels (as mention under the lighting section). A reasonably slow flow with macro's in beneficial as it allows more time for them to be exposed to the dirty water to uptake more nutrients. Some of the best macro-algae's are ones like
chaeto, dragon's breath, scroll algae (requires brighter lighting),
Dictyota ciliolata and pencil cap algae. Mangroves are a great, GREAT additions but require more work and a little more of a specific setup than what you'll be able to afford underneath your tank. I would love a display refugium with mangroves and clams!
Caulerpa sp. is another popular species of macro-algae for refugium and nutrient removal use but I wouldn't personally use it due to the fact that when
caulerpa sp. goes asexual it basically completely dissolves, releases all of the nutrients within it's system and spores everywhere throughout your DT, sump and fuge and can cause quite a problem to remove it completely from unwanted places but plenty of people love this macro! My first recommendation of a macro would always be
chaeto as it has a large surface area for nutrient uptake, provides excellent conditions for pods to grow in and around and it quite easy to care for
It grows quite quickly though s it may require semi to frequent pruning back.
Inhabitants (& Food Source):
With the addition of a refugium can come the ability to express a creativity that you can do with your DT as there is so much that can be added and tweaked to your personal preferences and the most beneficial outcome for your reef tank. The inhabitants and the way that you choose and pick the critters for your fuge will make it something that is your own. I'll break it down into three sections; pods, corals and inverts as these are the three main additions that are good in the fuge.
Pods:
we all know and love the amphipods and copepods that live in our tanks and feed our favourite friends that we care about so much. We also know how much how much our fish love them too and will happily demolish the tanks supply within days depending on the species. This is the other enormous bonus of a refugium, it provides a safe haven for pods to grow and live happily in a predator free environment. This means that there will always be a constant supply of the little guys in our tanks feeding our fish healthy live foods, that is exceptionally good for them. An even better way to make them even healthier and better for our scaly and polyped friends is to add enriched phytoplankton to the pods for them to consume and then pass onto or DT friends
Mysids are a great choice for a starter culture to add to your fuge as they are tough, grow quickly and will multiply rapidly.
Corals:
This is where you can really start to get creative and make yourself a display fuge (even though it will be under your cabinet).
Xenia sp. is a great addition for filter feeding corals to add to the fuge as they are easy to care for, grow quite quickly and also feed very actively.
Gorgonians and sea fans are also another great filter feeding coral to add but they are much harder to keep and will mean that greater care and attention is paid tot he DT and fuge to ensure they are healthy and happy.
Inverts:
These are the other bunch of critters that can really make your fuge very interesting. There are all sorts of little and big friends you can add. The most common occupants in a fuge aside from the pods is usually crabs that are unwanted in the DT. I don't really believe in killing anyone, unwanted or not which is why I think a refugium is another excellent idea as no one has to end up being "got rid of" so I find that a lot of people put any unwanted crabs or shrimps into their fuge for the same reason and it makes things a little more interesting too. Personally the day I have a refugium added it will become a Peacock Mantis Shrimp home (I LOVE those guys) but this is besides the point. Crabs are also good at controlling algae growth but not to the extent where everything becomes bare. Some people at clams as they are filter feeders but they require a serious setup due to their need for light so best avoid those for the moment.
I hope everyone has thoroughly enjoyed my post and found it quite interesting. Also I hope that it can help out a few people in making sense of this sort of thing in an easy-to-understand way
If anything doesn't make sense or you want any more info on anything, PLEASE, feel free to ask away
I really do enjoy helping people so no question is stupid or not worth asking!
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help or suggestions are greatly appreciated. 
