Well things have been rolling on nicely with the construction of the new aquarium. In the last article I covered the installation of the main pieces of equipment for maintaining the water chemistry and environment, now the tank has been fully aquascaped and stock has begun to be added. In this article I will cover the work involved in the aquascaping and maturing of the system, ready for the introduction of livestock.
At the end of the last article the tank had just been filled with RO water and the main circulation pump and heaters turned on, the next step was to start adding salt to the system.
The average salinity of sea water is 34.7ppt however it can vary greatly in different areas of the oceans. In tropical seas the salinity of the water is between 30 and 34ppt depending on location, however some areas such as the Red Sea have salinity levels of around 40ppt. For the most part aquarists use a salinity of 33ppt and this is what I tend to keep all my systems at.
When choosing the brand of salt for your aquarium there are a number of different ones specifically designed for reef aquariums which are all pretty good. There has been quite a lot of independent research into the different brands of salt and how closely they simulate natural sea water and a quick search on the web will provide you with pages and pages of articles so you can make an informed choice of what you want to use. I now use Tropic Marin Pro Reef salt for all my farming systems and have used it in this aquarium as well. The salt was gradually added to the system over a couple of days until the salinity reached 33ppt.
As this is a Berlin style system I am only adding a shallow sand bed which is formed of aragonite sand, I always use aragonite sand in any system as this provides a little buffering action to the water. Aragonite sand will slowly dissolve at lower pH levels found in your sand bed whereas crushed coral substrates will not. You can tell the difference between aragonite sand and crushed coral gravel or sand by washing them both in a cup of fresh water, the aragonite sand will slowly dissolve giving the water a slight milky appearance but coral sand will wash clean and the water will remain clear after it has been rinsed off. The buffering action provided by aragonite sands will only be slight but it is better than nothing, I generally find I need to top up my shallow sand beds once a year with new aragonite sand as it slowly dissolves. Carribsea and Natures Ocean are two brands of aragonite sand that are available in the UK.
For this aquarium I used 30kg of medium grade Natures Ocean aragonite sand to give a 1″ deep sand bed. Once the sand bed had been added I performed a 5% water change on the system replacing the water taken out with mature water taken from one of my other systems, this will have added a small amount of bacteria to help kick start the maturation process as well as other microscopic flora and fauna. I also added around half a kilo of mature sand from another system which contained more bacteria and other larger organisms such as copepods, isopods and worms to seed the sand bed. At this point I also added around 50 Dove snails and an inoculum of herpacticoid copepods.
In a reef system it is essential to have adequate water movement to enable the live rock to function properly and aid the respiration and photosynthetic processes occurring in the corals. If the water flow in a system is too low then water is unable to pass through the porous live rock and nitrification and denitrification cannot occur properly resulting in detectable levels of ammonia, nitrite or nitrate.
Corals also require good water movement to bring them oxygen, nutrients and to carry away the products of respiration, without good water movement the health of the whole system can be jeopardised. It used to be said that a level of water movement of 10 times the tank volume per hour is enough for corals but this value has been left behind. Although the flow of water through your sump should be at least ten times the volume an hour the flow of water around the main aquarium should be much higher, particularly if you want to keep sps corals.
There are now numerous types of water pump and wavemakers that are available on the market, some of them are very good and some of them not so good. I have spent a lot of time looking at the affects of flow and water movement on corals in my farming systems. In some of my farming systems I have turnovers of up to 75 times an hour and up to 16 different random flow patterns, however I cannot say that providing this great variety of different flow patterns has shown any significant difference in growth rates or health of the corals, in fact in some cases it is the corals that are exposed to continual flow in a single direction that have the highest growth rates. However, that having been said giving your reef system different flow patterns does seem to have benefits. By changing the flow directions in a system you are exposing different areas of the live rock and substrate to different flow patterns and this may increase the areas that are available for nitrification and denitrification, it also means that you may decrease the dead areas where detritus can build up.
Whatever make of pump you go for do your research first and don’t forget that a couple of well chosen pumps in combination with simple plug-in timers can work as effectively as the more expensive ‘wavemakers’. For my system I decided to try out the Seio Super Flow Pump, I had not used these types of pump before but what attracted me to them was the high flow rates and low cost of the units. I chose two of the largest models which have a flow rate of 10,000 litres per hour each and a RRP of £129.99. I already have around 5,000 litres per hour water movement coming from my return pump so this gives me a total of 25,000 litres an hour water movement around the main tank. In this volume of tank that gives me around a 50 times turnover per hour.
I fitted the pumps in the top right and top left hand rear corners of the tank, the pumps are designed to have a number of different mounting options but I found mounting them vertically to be the least obtrusive. The pumps have moveable water outlets so that I can customise the direction of the water coming out of them and I will be designing the rockwork and coral placement to disguise the pumps so that they cannot be seen when the tank is finished. One of the advantages of these pumps is that they have large water outlets which disperse the water quickly and over a greater area than powerheads would. This prevents the risk of coral tissue being stripped from their skeletons if they are placed close to the outlets of the pump which is something that can happen with some pumps and powerheads. One of the Seio pumps can be seen in figure 1 prior to it being disguised by the rockwork. I have also put rotating nozzles on the two outlets from the main return pump which means that I have four adjustable water outlets in the main tank. By connecting the Seio pumps to simple plug in timers I will be able to provide alternating currents within the tank.
Live Rock and Aquascaping
I decided to add the liverock to this system in two different instalments, mainly so that I had the opportunity and space to work on the aquascaping easily. I decided to use uncured Fiji live rock from TMC for the whole system. Using uncured live rock has advantages and disadvantages, the main advantage was that I was able to get the rock with as short a time period as possible between removing it from the sea and putting it into the aquarium. This means that I would maintain as much life on the rock as possible but also means that I would have to cure it myself which would take a little additional time.
TMC take delivery of their live rock on a Monday so I had the first instalment of 66kg shipped straight to me as soon as it arrived with them and I received the first three boxes on Tuesday morning. By then the system had been running with just the seeded sand bed, Dove snails and copepods for a week and you could already see a good population of Spaghetti worms, copepods and other worms and critters developing. On inspection of the live rock it seemed to be in good shape, there were plenty of different species of Polychaete worm both free living and tube dwelling species as well as molluscs, crustaceans and a few signs of coral polyps, all which were alive even if feeling a little sorry for themselves following their long journey half way round the world.
I put all 66kg of live rock straight into the aquarium separating the pieces according to size, then began the careful process of aquascaping the rockwork into the shape that I desired. I knew that I wanted an open design to allow plenty of water movement through the whole structure and at the same time concealing the few pieces of equipment that I had in the main tank and providing the future corals with a good base to grow from. I always build up the rockwork at either end of the aquarium, this draws your eyes towards the centre of the aquarium when you view it and hides the unnatural looking corners.
Larger pieces of live rock were used to give a solid foundation and then built upon piece by piece with more rock. You have to take this process slowly and use aquascaping putty to fix each new layer of rock in place and give the putty time to dry before working on the next level. I started on the left hand side of the tank and over the next day completed the majority of the aquascaping for the left hand side of the aquarium. Figure 2 shows the first part of the aquascaping complete.
I then went on to construct the main part of the central portion of the tank which can be seen in figure 3 As you can see although not finished the structure is quite open providing lots of swimming spaces for the fish and interesting areas for the corals to grow from. I then left the tank for a while as this was uncured rock and the system was going to need time to cycle any dead plant and animal matter.
The skimmer was running to help reduce the load of decomposing organic matter on the system and hopefully the fact that the sand bed had been seeded a week before would lessen the impact of all the uncured live rock on the water. During this time I kept the T5 tubes lit for about 5 hours a day (but not the halides) to ensure that photosynthetic organisms did not perish. I also placed in the tank a large frag of Montipora digitata, this is a very hardy species of sps coral that would act as an indicator for me as to how the water quality was, this can be seen at the top of the middle portion of rockwork in figure 3.
To be honest I did not bother to test for ammonia or nitrites as I knew that there would be spikes that would quickly disappear again, but I did monitor the nitrates as I knew these would climb very quickly and then if everything was right would drop quite quickly too. After three to four days the nitrate level had climbed to 50ppm and by the end of the first week this had increased to around 100ppm. I kept a close eye on the population of critters in the aquarium and despite the high levels of nitrate they appeared to be fine and their numbers were increasing and the Montipora frag that I had put in there was still alive but looking a bit sorry for himself.
At the beginning of week two I performed a 15% water change with water taken from one of my other systems and 10 days after the live rock first went in the nitrate level had dropped to 75ppm. By the end of the second week the nitrate level had dropped to around 35ppm and the Montipora frag was looking much happier. There were some low levels of phosphate detectable so I used a little phosphate remover in a fluidised reaction chamber to deal with that and I also ran some carbon for a couple of days to deal with any colourants and toxins from die-off of organisms. I then put in the next order for live rock and also ordered a dozen Turbo snails and a Yellow Tang (Zebrasoma flavescens). By this time there were various types of macro algae that had started to spring from the live rock and I needed to get some grazers in there to deal with them, I was a little concerned about the presence of the nitrates and adding the fish at this time but it did not seem to present any problems for it and the fish quickly despatched much of the new growth of macro algae.
There is still one type of algae though that is present that Z. flavescens will not feed on and that is Sargassum spp. (figure 4). This is a very large type of brown macro algae that has very strong holdfasts and can grow quite prolifically, but there are a couple of species of fish that I know of that will feed on it if it becomes a problem.
The second delivery of live rock consisted of 44kg but this time I did not want to add it directly to the system as I did not want to cause any ammonia or nitrite spikes so this time I put it into a large tank with mature water taken from another system along with a heater and a strong water pump. I left it in there for two days to help remove the majority of the dead organisms from transit and then transferred it to the main tank towards the end of week three.
The rest of the aquascaping for the right hand side of the tank and finishing touches for the rest of the rockwork can be seen in figures 5 and 6. I used 110kg of uncured live rock and an additional 15kg of nicely shaped pieces that I already had giving a total of 125kg of live rock used in the system.
Over the first four weeks I kept the protein skimmer running constantly and the calcium reactor has been running at a slow drip rate but other than that, the water changes and the little phosphate remover and carbon that I mentioned I have done nothing to the system. The water parameters one month after the live rock was first put in were as follows.
Nitrate: 0.5ppm Phosphate 0.00ppm pH: 8.15-8.30 over 24 hours dKH: 9.2 Calcium: 420ppm Mg: 1550ppm
The rockwork is really springing to life now with copious amounts of tube worms, sponges, forams, tunicates, bryozoans, hydroids, molluscs including bivalves and even a few different coral polyps coming out. I was also very surprised to find a baby Sea Hare in there, I noticed him for the first time about 3 weeks after the first lot of live rock went in there, it was about an inch long at the time but has now more than doubled in size since then.
Although the water parameters are good and I have now added a few more corals there are still a few things to sort out. The nutrient levels are still a bit high but these will come down in time and there is still a bit of a diatom growth and the Sargassum is going to need to be dealt with, however that having been said, the few species of coral that I have added are flourishing and growing. I also need to increase the numbers of grazers in there although the Dove snails are already starting to breed so that will help. The next stage of the construction of the system will be the stocking of corals.