If you’ve followed the instructions in part 1 you should now have your tank pretty much ready for live rock.
For this article you will need (you should have most of this already):
Filtration, What Is Live Rock?
Live rock is an amazing resource. In this tank, and other Berlin system tanks like it, it will take on numerous roles; it will be our primary biological filtration media, our décor, a structural support for a plethora of sessile invertebrates and a complex network of burrows and homes for the creatures that hitch a ride from the sea to your tank!
As in any biological filter the aim is to provide maximum surface area for bacterial colonisation, this is where live rock excels as a filter media. The rock is highly porous with a truly enormous surface area for nitrogen fixing bacteria to colonise, but, it is within the rock where the magic truly happens. Live rock often contains channels, tunnels and cavities deep within it, these cavities are shut away from the rapid flow created by the waves in the sea or powerheads in your tank. In these shelters anaerobic conditions develop and support de-nitrifying bacteria. As the nitrifying bacteria on the oxygen rich surface convert Ammonia to Nitrite and then to Nitrate the anaerobic de-nitrifying bacteria continue to convert this Nitrate into Nitrogen which escapes harmlessly at the surface of the water. In effect each piece of rock is capable, in the right conditions, of supporting the entirety of the Nitrogen Cycle on it and within it, which makes this material a truly valuable resource for any marine tank.
Buying Your Live Rock
Buying your live rock is perhaps one of the most exciting and expensive stages in the development of your marine tank. Because of this it is more important than ever that you make sound choices with regards to selection and transportation of your live rock.
Some things to consider are:
You should source ‘cured’ rock wherever possible. You may see ‘uncured’ rocks at a fraction of the price but don’t be tempted. Curing live rock is a process of maturation whereby the rock, after transportation from harvest to retailer, is placed in large vats for a number of months, any critters within the rock which died during transport will decay and produce Ammonia, the rock in effect is cycled and matured prior to sale. In this time, significant populations of reef critters and pods living in the rock will die. If you buy uncured rock this process will happen in your tank, your tank will endure a heavy cycle and significant life will be lost reducing the overall biological activity and future potential of the rock. All rock is cured at some point but much better that this is done in large industrial vats with a water volume capable of better diluting the toxins produced, than in the confines of your tank. If you truly wish to see the full potential of your live rock over the coming years then choose cured rock.
Always ask where your rock comes from, this will give you an inclination as to the quality, variety of life you will encounter on it and the nature of its harvest. Indonesian, Fijian and Tongan rock are common in the hobby (in fact the majority of live rock is harvested in the South Seas), Indonesian is reputed to be, on average, significantly more porous than Fijian, Tongan is solid, dense and stronger than the aforementioned choices. Other varieties are available but always research the nature and location of harvest. For a more ethically sound choice try to get hold of aqua-cultured live rock. This is bare, volcanic rock which has been placed in the sea, allowed to mature and later harvested, this process relieves the harmful and destructive effects of coral reef rock harvesting, expect to pay a premium for this ‘man made’ live rock.
So you’ve assessed where the rock comes from and whether it is cured or uncured, if that checks out then it’s time to take a look at the pieces of rock on offer!
Look out for obvious pests like Aiptasia (see Fig 1), Majano Anemones, large worms and pest shrimp/crabs. Also keep an eye open for beneficial freebie corals and other invertebrates. Most live rock will come with a variety of polyps and corals tucked away in crevices which will grow once placed in your tank. Don’t be afraid to take a book with common invertebrates and pests listed with pictures, once introduced to a tank many pests can be incredibly difficult to control or remove. Many pests can be hard to spot so don’t fret too much about spotting everything, a cursory glance over each piece for obvious pests would be an adequate/reasonable precaution against their introduction.FIG 1) (Source)
Now consider how each piece of rock will fit together and have an idea before you buy of what your aqua-scape will look like. Get a good mix of base rock pieces (pieces with a flat edge to rest on the egg crating at the bottom of your tank, ie good building blocks) and interesting shapes/feature pieces, and/or particularly porous pieces. To save on money some keepers build the base of the display with dead ‘Ocean Rock’. This rock will eventually be colonised and become live over a number of months and years and so whilst the benefit is only seen long term it can represent a significant saving in larger tanks.
Getting Your Live Rock Home
A good marine stockist should provide you with some tubs and saltwater to transport your live rock in. It is very important that wherever possible the rock is kept underwater to avoid die off. Transport should ideally be less than an hour and the rock should be placed in a stable, pre-tested (for pH, temp and specific gravity) tank as soon as you get it home.
Do what you can to aqua-scape under water, and ensure that the rock is solid and not prone to tumble. Experienced aquarists use marine safe rock putty to bond the rocks together to avoid nasty accidents and smashed tanks! Remember to place a base layer of egg crating under the rock to provide stability and protect the pane of glass which constitutes the floor of the tank.
Once the rock is in position you can place your sand around it, ensuring that you cover the egg crating. Layer the sand to a depth of approximately 2 inches.
Additional Chemical, Mechanical and Biological Filtration
You are now ready to add additional filtration into the rear chambers of your tank. You should have some phosphate absorption media, some Carbon, some filter floss/wool and your live rock rubble in a filter bag.
Here is a reminder of what the chamber layout looks like:
In the Orca 550 – Firstly cut a piece of filter floss to a size which enables it to run the depth of chamber 3 with a little overlap into chamber 2. Now peg the overlap to the divider between chambers 2 and 3 and press the wool flat against the dividing wall. You may need to weight the wool so that it stays weighted towards the bottom of the chamber (a plastic aquarium feeding clip is significant enough to keep the floss weighted to the bottom of the chamber and is inert so will not pose a risk to water quality). All the overflow slots in the dividing wall should now be covered with filter wool which will help to trap fine particulate matter. This media should be changed weekly; you may find that changing it daily for the first week of your setup is required (due to fine sand particles etc. after introduction of rock and substrate).
Now place the live rock rubble in the bottom of chamber 2, it should sink easily. On top of this place your phosphate absorption media, flatten this out in the filter bag provided with it so that it resembles a pancake (this media should be replaced once exhausted, regular testing will indicate when this is due), ensure the water cannot flow around it. Lastly place your Carbon (replace monthly) on top.
In the Orca 450 – Firstly cut a piece of filter floss to a size which enables it to run the depth of chamber 4 with a little overlap into chamber 3. Now peg the overlap to the divider between chambers 4 and 3 and press the wool flat against the dividing wall. You may need to weight the wool so that it stays weighted towards the bottom of the chamber (a plastic aquarium feeding clip is significant enough to keep the floss weighted to the bottom of the chamber and is inert so will not pose a risk to water quality). All the overflow slots in the dividing wall should now be covered with filter wool which will help to trap fine particulate matter. This media should be changed weekly; you may find that changing it daily for the first week of your setup is required.
Now place the live rock rubble in the bottom of chamber 3, it should sink easily. On top of this place your phosphate absorption media, flatten this out in the filter bag provided with it so that it resembles a pancake (this media should be replaced once exhausted, regular testing will indicate when this is due), ensure the water cannot flow around it. Lastly place your Carbon (replace monthly) on top.
The Cycle - Ammonia (NH3), Nitrite (NO2), Nitrate (NO3)
During transit, some live rock die off will have occurred, this is largely unavoidable, transit precautions are merely a method of reducing overall die off to maintain long term potential. This die off will inevitably create an Ammonia (NH3) spike. This NH3 spike will trigger the cycle. How long this takes will largely depend on how much die off occurred. It is possible, though unlikely, that die off is so minimal that a cycle will not occur and in effect the tank will be ‘instantly cycled’ with addition of the rock. It is much more likely however that you will soon see the NH3 spike mentioned above and a routine cycle spanning on average 1-2 months will occur (only routine testing will tell either way). The compounds you will encounter are detailed below. Only when you consistently read 0 for NH3 and NO2 can you claim to have completed the cycle. Throughout the cycle, best practice is to maintain a series of small water changes to minimise build up of NH3 and NO2 which could cause further live rock die off.
All marine keepers should understand the significance of NH3 in marine aquaria. For mature aquaria presence of readable NH3 is (or rather should) be a rare or non-existent occurrence outside of the initial cycle.
NH3 is a caustic and highly toxic compound of Nitrogen and Hydrogen (1 Nitrogen atom, 3 Hydrogen atoms hence NH3), it is extremely dangerous to the majority of life found in the seas and can kill quickly or leave irreparable damage even in small amounts. Despite this, it remains one of the most important compounds on the planet as one part of what we call the Nitrogen Cycle, the process by which Nitrogen is captured and processed into usable forms by living organisms. It is the underdeveloped state of this cycle that causes the greatest of problems in domestic aquaria (The Nitrogen Cycle is very rarely absent all together. In new setups the absence of Nitrogenous compounds keep bacterial levels low, as the colony is supplied with more ‘food’ it can grow and support the bio load of more complex organisms).
The process starts with Nitrogen (N), one of the most common elements on the planet, we place it into the food chain when we feed our fish (Nitrogen is a fundamental building block in Protein), or when a creature dies and decays. Metabolism of proteins creates Urea, of which one of the main constituents is NH3 (NH3 is also produced by decomposers, bacteria and fungi). It is the action of Nitrifying bacteria (Nitrosomonas - note differing strains for different stages of the cycle) which convert this NH3 in to Nitrite (NO2). This reaction requires Oxygen (O2) as shown below.
NH3 + 3/2 O2 → NO2- + H+ + H2O
NO2 is slightly less toxic than NH3. In freshwater aquaria it constitutes a significant risk to the health of your livestock. NO2 converts Haemoglobin (the substance responsible for transporting Oxygen in the blood stream) into Methemoglobin which is incapable of carrying Oxygen. Obviously this presents a significant risk to living organisms’ dependant on the use of haemoglobin for respiration. In Marine aquaria the presence of salt inhibits this conversion, leaving the presence of NO2 indicative of poor water quality rather than a significant risk by itself. (However, ‘poor water quality’ poses associated risks and should be dealt with appropriately). Nitrifying bacteria (Nitrobacter) are now responsible for a further transition, converting the NO2 into Nitrate (NO3). The process of oxidation (addition of O2) continues in the reaction as shown below.
NO2- + ½ O2 → NO3-
NO3 is significantly less toxic than NH3 and NO2, and in small amounts is relatively harmless to marine life. Somewhere under 10ppm in Reef aquaria (Fish and Inverts) and anywhere below 20ppm in Fish only or FOWLR (Fish Only With Live Rock) systems. Ideally however a reading of 0ppm or close is the optimum and certainly achievable in many systems. In the sea the presence of NO3 is negligible and so in the confines of our marine tanks we should try to simulate this level as best we can. Whilst higher levels are acceptable and in many cases harmless we should endeavour to provide the best we can and the nearest environment to the sea as possible. Frequent partial water changes are used to keep NO3 at a minimum and top up essential minerals.
In some marine tanks NO3 can be kept to a minimum by de-nitrifying bacteria (e.g. Pseudomonas and Clostridium). These bacteria can only do this in anaerobic conditions (areas starved of O2, as opposed to the earlier reactions dependant on O2). The majority of aquaria simply do not have large anaerobic pockets as this is seen as undesirable, and certainly can cause problems in some circumstances (waste products produced as a result of anaerobic respiration can be hazardous, Hydrogen Sulphate (HSO4) for example). In many live rock based systems however bacteria like this can thrive (in the depths of the rock and sand beds). These bacteria work to release the captured Nitrogen (from the NO3) and distribute it back in to the atmosphere, thus completing the Nitrogen cycle. The process of de-nitrification does not replace the need for regular water changes.
Testing daily will allow you to track the levels of the above mentioned compounds. Once NH3 and NO2 are 0 consistently for at least two weeks (or at least a month after setup, whichever is the latest) you are ready to run one final water change to reduce NO3. Your now in a position to start adding your clean up crew (discussed in part 3), but first we need to take a look at some other water chemistry principles and the important role the skimmer will soon play in this setup.
Basic Water Chemistry
In this section I’ll try to briefly summarise what each of your test kits measure for and what the tests mean in a general sense. How each of these components interact with each other (and interact they do) is beyond the remit of this article and deserves an advanced water chemistry article of its own. The information below should be enough to give you a solid understanding of the basics.
For this we shall look at pH, Carbonate Hardness/Alkalinity, Calcium (Ca), Magnesium and Phosphate. These are the basic tests you should be running at least weekly in addition to the tests outlined in ‘The Cycle’ section above and frequent Specific Gravity measures as outlined in Part 1 of this article.
pH (Potential/Power of Hydrogen) measures the acidity or basicity (sometimes confusingly referred to as Alkalinity) of a substance on a scale of -1 (Acid) to 14 (Base), Neutral is widely accepted as being close to 7 on this scale. The pH scale is logarithmic; a reading of 5 is ten times more basic than 4 and 100 times more basic than a reading of 3 and so on.
The optimum pH range for marine aquaria is 8.1 to 8.4; reef aquaria tend to benefit from stability at the top end of this range. This is largely to do with the assumed mineral content of the water at a higher pH.
pH and ‘Alkalinity’ as discussed later (not to be confused with basicity) are involved in a somewhat complex relationship, movement of the former is often the direct reaction to movement of the latter.
The term Alkalinity should not be confused with the same term relating to position on the pH scale (referred to as basicity to avoid confusion). The Alkalinity of a substance does not in fact refer to its basicity or position on the pH scale, rather it refers to a sum of its parts working to make the solution more basic (higher pH). For example, a pH reading will detail the effect on neutral of all alkalis and acids in the solution, whereas an Alkalinity measure will detail only the substances working to make the solution more basic. For example a solution of pH 8 may in fact contain a strong acid, only to be countered by an even stronger alkali which pushes the pH up to 8. So pH doesn’t tell you at a glance how strong the alkali is merely the end result of its balance with acids.
Alkalinity is often referred to as Carbonate Hardness (Kh), the relevance of this term is due to the prevalence of Carbonate and Bicarbonate as constituents of Alkalinity (these substances being the most common alkalis contributing to water hardness). Other substances (such as Hydroxide, Silicate and Sulfide) can contribute to Alkalinity so a measure of Kh may not necessarily reflect total Alkalinity.
So in summary Alkalinity refers to all the ‘ingredients’ of a solution working to increase basicity, adding an acid to this solution will lower the basicity NOT the Alkalinity.
Kh in seawater is around the 7dKh mark, in a marine tank a reading of 7-12dKh is perfectly acceptable.
Calcium (Ca) is one of the most common constituent elements of sea water, representing anywhere between 10 and 15% of total solid matter contained within it.
Corals and other invertebrates harness Calcium and Carbonates to construct their skeletons, shells and homes making this element particularly important to reef systems, though its relationship with Kh/Alkalinity and the subsequent knock on effects on pH should be acknowledged and respected in any marine aquarium.
Optimum range for Ca is anywhere between 400ppm and 450ppm. Levels should be balanced appropriately with those of Magnesium and Kh/Alkalinity (within their respective optimum ranges).
Magnesium most commonly piques the interest of marine aquarists due to its relationship with Kh/Alkalinity and Calcium levels (though in truth it has a large number of biological and chemical applications), it is this relationship which tends to have the greatest impact in marine aquaria.
Magnesium allows the retention by seawater of significantly higher levels of Carbonate and Calcium ions than would otherwise be possible, allowing for greater pH stability. Both Carbonate and Calcium will bond with Magnesium thus preventing the bonding of Calcium and Carbonate together and the subsequent precipitation out of solution. Magnesium is also known to attach to formed Calcium Carbonate structures to prevent further precipitation onto, or dissolution of, the structure in question.
Magnesium should be maintained at levels of at least 3 times that of Calcium (when Calcium is within optimum ranges of 400-450ppm), i.e. 1200-1350ppm is ideal.
Phosphate is relatively harmless to marine life in low concentrations, it is in fact one of the most important nutrients for the proliferation of a huge range of algal and plant life, it’s absence can be a critical limiting factor in plant/algal growth.
Although posing very little threat by itself, high levels of PO4 can spur rampant algal growth, not only is this usually highly unsightly but can pose a significant threat to sessile invertebrates (the algae out-competes for nutrients and smothers the surface of corals/clams etc).
PO4 is introduced to marine tanks in a number of ways, through feeding, un-filtered tap water, poor quality salt and substrates, and poor quality additives such as pH and Kh buffers. Limit at the source by using RO (Reverse Osmosis) water rather than tap, thoroughly washing live/frozen foods in RO water before feeding, and buying the best additives you can afford specifically those which state PO4 free/low. You should also actively target PO4 reduction in the tank at all times as it is almost impossible to stop introduction altogether. This can be done in a number of ways, with both chemical and biological filtration (turf/algae scrubbers for example).
You should test for PO4 regularly, the optimal reading for PO4 is 0ppm, anything up to 0.03ppm would be acceptable but may be cause for action, anything over this requires attention.
Now run your first battery of tests and make note of them. You should at a bare minimum log each week’s results in a note book. Preferably plot them on some kind of chart or graph in order to recognise trends and calculate accurate doses of additives to counter deficits/imbalances.
The Skimmer, and Preparing the Tank for Livestock
Ok, by now you should have your tank pretty much ready for livestock. You’ve filled it with water, added your live rock, allowed the tank to completely cycle/mature and made note of your water readings and adjusted chemistry with water changes as required. If you’ve followed the instructions from part 1 of this article then the only thing that should still be un-plugged/un-used is the skimmer. You’re probably wondering why right about now?
Implementation of a Protein Skimmer, along with the Live Rock and circulation pumps, constitutes one of the key principles of Berlin filtration. Protein skimmers remove the un-desirable wastes and by-products of biological metabolism (remember earlier how we discussed that Proteins could be broken down into Nitrogenous wastes/compounds) which would otherwise build to hazardous levels if allowed to persist.
Skimmers work by streaming microscopic bubbles through the water column (an air pump creates bubbles which flow up through the body of the skimmer), as these bubbles move through the water they attain a charge. The charge, whether positive or negative, attracts a range of undesirable substances depending on the charge contained within them (opposites attract). The bubble then travels through the neck of the collection cup and bursts as it reaches the surface, the effluent carried with it is deposited within the collection cup and routinely removed by the aquarist.
So why have I not been using this so far?! Protein skimming is only effective if there are proteins and other wastes there to skim, these wastes will only be present when there are complex organisms such as fish and invertebrates living in your tank. Using a skimmer without these wastes present will often result in overflowing micro bubbles which permeate the entire tank.
Switch the skimmer on when you have added your first livestock (discussed in part 3), the skimmer will be a little noisy for a month or so, allow some ‘bedding in’ time before you see notable results in skimmate production (remove any skimmate weekly).
Hopefully you should now have a basic understanding of water chemistry and the filtration techniques you will employ over the lifespan of your marine setup. In addition you should now find yourself in a position to contemplate addition of clean up crew invertebrates, fish and your first corals. All of this we’ll discuss in part 3!
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