When you first get started keeping Saltwater it can get overwhelming really quickly. A great piece of advice I was given when I first started was "the hobby is really about keeping water, focus on keeping your parameters in check and the rest will fall into place". So that's what I did but there's so many parameters out there and so much conflicting advice about what to keep them at that it can still be pretty confusing. So, here's a quick rundown of the main parameters, what they mean and what can affect them plus at the end I'll reveal the ultimate reef keeping piece of advice! Now that's something to stay for and read right?
Salinity.
How salty is your salt water basically. There are two main measurements for it but the most common is PPT (Parts per trillion). You want to aim to keep your water at 35PPT. The other measurement is SG (Specific Gravity). 35PPT in SG is 1.026. There are two good ways to measure salinity and that is with either a refractometer like the Red Sea Refractometer or by using a digital refractometer. Swing arm and floating test kits can be unreliable so try not to use them. Salinity in your tank can increase due to evaporation which is why it's important to top up your tank with RO water not salt water. Salinity can also gradually decrease due to things like your skimmer removing salt water and salt creep which is when salt water dries on equipment leaving salt crystals out of the water.
Temperature.
How warm is your water. Coral reefs exist in the tropical regions of the world so the water is a bit warmer than off the coast of Britain! There's some debate over what temperature is best but 24c is a popular temperature and is what all the systems in Rock N Critters are kept at. There are two main things that affect water temperature; ambient air temperature and equipment malfunction. In summer the air temperature in the UK can rise and cause tanks to overheat. To prevent this you can use a temperature controller like the D-D Dual Temperature controller which can control a heater and chiller to maintain water temperature. The other problem can be equipment malfunction or power cuts. We have little control over power cuts but we can choose our heaters. Glass heaters can break easily so the best option is to use a titanium heater like the D-D Titanium Aquarium Heater.
Nitrate & Phosphate.
Now we're getting into nutrient control! Without getting too in depth, Nitrate (NO3) and Phosphate (PO4) are a result of the biological processes in your tank.. Fish waste! There are other contributing factors and nutrient control is a big topic all in itself but when you're starting out really all you need to know is that they exist and they need to be controlled. You can test for them using test kits like Red Sea Nitrate Pro Test Kit and the Red Sea Phosphate Pro Test Kit. To control them you need to adopt a method of filtration, now this is another topic all in itself but the most common piece of equipment at the heart of filtration is a Protein Skimmer and some sort of mechanical filtration such as a roller mat like the Clarisea or filter socks. At Rock N Critters we also use Arcadia Marine Bio Pearls in a reactor. Nutrient control is ultimately about balance though. Balancing how much
livestock you have in the tank and how much you feed it against your filtration setup to manage the level of Nitrate and Phosphate. What levels should I have though I hear you ask. You guessed it, its a huge topic with many reefers doing different things. If you want a fish only system then the levels don't have to be super low, Nitrate below 10PPM and Phosphate below 1PPM is a good benchmark but if you're looking to keep a reef with coral, especially SPS then you should be aiming for Nitrate at 1-4PPM and phosphate below 1PPM. Whilst it's important not to let these levels spiral out of control it's also important not to let them get to zero. The aquarium needs some Nitrate and Phosphate to function or else it can cause what is known as a tank crash.
Alkalinity.
Now we're heading into chemistry. This is where it can start to get really science heavy and there are some really in-depth reef chemistry discussions out there but for the purpose of this blog I'll keep it as simple as possible. Alkalinity is the measurement of how acidic the aquarium water is. We measure this because we want to know what the carbonate levels are in the aquarium but its quite difficult to test for so instead we test for Alkalinity which is related to the presence of carbonate in the water. Why do we want to know about carbonate in the water? Corals, coralline, algae etc all use carbonate to build and maintain their skeletons and biological structure. Maintaining stable alkalinity is a key factor in keeping a stable aquarium. How do we test for it? We can use a test kit like the Red Sea Foundation Pro Test Kit. It will give us a measurement in dKh (sometimes shortened to Kh). Natural Sea Water is about 7dKh but guess what! Yeah you're right, there is loads of discussion and debate about what level to keep dKh at in the reef aquarium. At Rock N Critters the Coral systems are kept at around 9dKh. My reef tank at home is at about 8.7dKh which is the sweet spot I've found my reef to be happy at. What can affect dKh? A number of things, fluctuations in other parameters can have an affect on it and as corals and algae etc start to grow they will consume carbonate thus causing Alkalinity levels to decrease. Alkalinity is a really important parameter to keep stable especially when keeping coral. One of the best ways to do this is by using a calcium reactor.
Calcium and Magnesium.
Continuing the theme of chemistry let's talk quickly about Calcium and Magnesium. These elements become important when you start caring for corals. Coral uses Calcium and Magnesium to support and grow their skeletons which ultimately keeps the coral alive and healthy long term. You can measure both of these at home with test kits such as the Red Sea Foundation Pro Test Kit and they will give you results in PPM. If you're keeping coral then you want to be aiming for Calcium to be between 412 - 450 PPM and Magnesium to be 1300 - 1500 PPM. The same things that affect Alkalinity can affect both Calcium and Magnesium. You can manage levels by using a calcium reactor or dosing supplements. Always be cautious about dosing supplements though. You should never dose anything to your tank that you are not actively testing for. Accidently overdosing something to a reef tank can be disastrous! Test, test, test!
So that sums up the basic parameters, if you can master these then you have the foundation for a stable and healthy reef tank! I mentioned home test kits for monitoring these parameters but there is another option. ICP testing. ICP testing will analyse your water for all major and minor trace elements. It gives you a read out on elements you never knew mattered! My advice would be, when you're starting off just focus on the main parameters in this blog. Once you've done that then consider an ICP test to fine tune your reef.
As for the ultimate piece of reef keeping advice, I've alluded throughout the blog that there is a lot of debate about what level parameters should be. Some say keep this at that and others say keep that at this. There are pros and cons to all of them and reef keepers from all sides of the debate are having success. The common denominator between these successful reefers is stability. Whether you keep DkH at 7 or 10, Nitrate high or low or the temperature at 24c or 25c, the commonly agreed factor to success is that the parameters are kept stable and do not fluctuate greatly. When we look at coral reefs in the wild, they thrive because the parameters barely change at all over time, hence
why global warming and acidification of the reefs are understood to be major factors in relation to coral bleaching. That is the real challenge of this hobby I think, keeping many different parameters perfectly stable over long periods of time. There we are, we've come full circle, look after the water, keep it stable and the rest will fall into place!
P.S, there's a printable Rock N Critters parameter guide here.
SEE ALSO: The Question Is, What Is The Question?