When I got home from that first trip to a reef shop I felt like I had a mountain to climb, there was so much I needed to know, so many questions and so much I didn't know I didn't know. So I fired up the dial up internet and began to slowly trawl the forums. As in any hobby, once you get into it you begin to take some knowledge for granted and just assume that everyone else knows it too which is why sometimes I think it can be hard to find straight up answers to those initial questions, so that's what this blog post is about. The questions that I had when I first started that when I think about it I often take for granted now.
What is RO water?
RO or Reverse Osmosis water is water from the tap that has been filtered to such an extent that that it removes all the impurities. You have to use a RO machine which houses specific fine filters and resin to process tap water into RO water. It can be a slow process and you won't get a 1:1 ratio of tap water to RO water. There will be some wastage. If you make RO water at home you'll have to plumb in the RO filter to your mains and waste pipe. It's easy enough to do but if you don't fancy doing that then you can get RO water from Rock N Critters. You can get salted RO water too for ease! In fact, Rock N Critters use RODI water which is the next question below.
Is RODI different to RO?
RODI is just Reverse Osmosis Deionization water. It's the same as RO water but with an extra stage of filtration on the end that results in a lower TDS (Total Dissolved Solids) in the water. TDS is what we use to measure how pure RO water is. We're aiming for a TDS of zero. When talking about water, RO is often used as the catch all term for both RO and RODI water.
How do I know how much salt to add to my RO water?
Depending on what salt brand you are using will depend on how much you need to add. There will be instructions on the side of the salt container telling you how much to add in order to achieve the desired salinity of 35PPM. If you’re mixing your own salt though you need to mix it when the water is at the correct temperature range else it can cause inconsistent salinity readings. Also, never add salt directly to your aquarium once it’s up and running. Always mix it separately and then add the mix.
How do I get the right PH?
The salt will automatically give you the PH you need so don’t worry about it too much. There is some debate and research about PH and how it affects a reef tank specifically in relation to coral health and growth. When you’re starting out though you don’t need to worry so much about this.
Should I have a deep sand bed or a shallow?
This is one of those topics that gets debated a lot. The deep sand bed philosophy comes from the older school of thought that a deep sand bed will create anaerobic zones which will assist with denitrification of the tank. Essentially it will help with filtration. It’s argued however that this just causes sediment to form in the sand bed until its accidently disturbed by you or by fish at which point it sends plumes of dirt into the water column releasing all that bacteria and detritus which can cause nutrient spikes in the tank. The alternative is to have a shallow sand bed where the sand is at max 1 inch deep. In this case the sand is there more as a decorative feature to give the tank a more natural appearance rather than filtration although it will still host some bacteria and help stabilise the tank. The third alternative is to go bare bottom which is when you have no sand at all. There are some really nice bare bottom tanks out there although in my opinion these all have coral covering the bottom. The tanks that don’t have coral covering the bottom look okay until they get dirty at which point you need to spend the time cleaning the algae off and any detritus that may settle. The BRS team over in the US did an interesting study on the effects of bare bottom tanks and found that sand in fact helps a new tank achieve stability, reduces bacteria outbreaks and they said in their opinion the fish seemed happier in a more natural environment. Me personally, I agree with them and I have a shallow sand bed in my home reef tank even though the goby does his best to move the sand about in piles!
Fish only system, reef compatible, reef with caution. What does it all mean?
Fish on the reef all eat different things. Some eat other fish, some eat invertebrates like shrimp and crabs whilst others eat coral. ‘Fish only’ are the coral and invertebrate munching fish. ‘Reef compatible’ won't eat coral and/or invertebrates whilst ‘Reef with caution’ are somewhere in between and that is where is starts to get tricky because some fish will eat soft coral and not SPS coral or vice versa. Some fish can take a particular liking to one specific type or coral as well. I have a Coral Beauty Angelfish which for a while loved eating Pocillipora (one of my favourite corals!). So whilst we group fish into these categories it can also depend on the temperament of that individual fish. My advice is if you like a fish, do plenty of research about it and make sure it’ll be compatible with your tank and inhabitants. Never impulse buy livestock!
Are big tanks easier than smaller nano tanks?
Generally speaking yes. A smaller tank is a smaller amount of water so parameters are likely to change quickly and stability is the key to a healthy reef tank. The best analogy of this is imagine a dinghy and a huge cargo container ship. The dinghy is small and nimble, can change direction quickly and easily but is less stable compared to the big cargo ship which moves slowly, changes direction slowly but is more stable and is less likely to capsize. Compare this to a nano tank vs a four foot reef tank and it holds true.
I read I can have Xcm of fish per 100litres, is this true?
I don’t like this rule of you can have so many cm of fish in a reef tank. It’s a rule that has been brought over from freshwater fish keeping and in my opinion, I think it encourages poor fish stocking and husbandry. When deciding what fish and how many you want in your reef tank there are a few things to consider. Will these fish get along? Some fish are notorious for fighting with each other whilst others can be very shy and just won’t enjoy being around boisterous tankmates. What bio load can your filtration handle? You could have a 10 foot tank capable of stocking a huge amount of fish but if your filtration method can only handle half that amount of fish then that’s all you should have. No-one wants to live in dirty water! Consider how big the fish will grow as well for two reasons; a big fish will produce more waste than a little one and how much space will that fish need to swim around in? Keeping a 1 foot long fish in a 2 foot cube is not fair.
What lights do I need?
This all depends on what you intend to keep in your tank. Not all lights are made equal! There are three main types of light however, Halide bulbs, T5 Bulbs and LED. LED is by far the most popular choice now due to controllability and lifespan however there are plenty of people still using Halide and T5. At Rock N Critters there is a Halide lamp over the downstairs sump and LED over most of everything else. If you’re in the shop in the afternoon you can sometimes hear the Halide turn on. With LEDs the problem comes with spectrum of light and intensity. Whilst a Halide or T5 bulb emits an omni directional beam of light an LED emits a focussed narrow beam of light which can be too intense for corals. This is what we refer to as ‘spread’. What you ideally want is a blanket of evenly spread light across the tank and not narrow areas of intense light. Spectrum of light is important too. White light is made up of many different colours that we can see and colours that we cannot like Ultra Violet and Infra red, this is known as the spectrum of light. Corals need a spectrum of different light in order to survive and grow. The problem lies in providing the correct spectrum. LEDs emit single colours so manufacturers create light fixtures with different coloured LEDs to generate the desired spectrum. The next problem comes with blending those colours together to create an even spread of the correct spectrum. This is why many big LED manufacturers like EcoTech Radion and Phillips Coral Care now have diffuser plates below the LEDs to help blend the light. There are
working examples of a few of these different fixtures in the shop over the different systems so feel free to come and have a look, one of the team will be able to talk you through the different fixtures and their features. It all makes sense when you can see it in person I think.
So that’s just a few questions that I know I had when I was first starting. I know there’s so many more though but I don’t want to bore you all with a 10 000 word blog post. Let me know what you would like me to answer or research and I will! Or alternatively pop into the shop and have a chat with one of the team, they’ll happily help out!