Continued from page 2Source Water:
Although we all start off with the best of intentions for our reef tanks, choosing the best equipment, carefully planning the plumbing and what pumps to use, we often overlook the fresh water that we will use to make up the saltwater ultimately used in our tanks. Using the best salt is a good start but the freshwater used has to be just as good if we want good consistent results.
There are several ways available to the hobbyists to have good freshwater. One can use Reverse Osmosis (RO), Deionization (DI), RO/DI in combination or one can purchase distilled water from a supermarket. one can also buy a distiller for home use but these are a little on the expensive side. They are useful for hobbyists who have need to filter their drinking water extensively.
Reverse osmosis works by pushing the water through a permeable membrane which allows only pure water molecules to squeeze through while selectively filtering the contaminants out. This produces two outputs. One with pure water and one with the waste contaminated water which can be disposed of. Reverse osmosis units are slow, often times producing only 25 gallons per day depending on the unit that is purchased.
Typically, one gallon of usable water is produced for every six gallons that are wasted. However, the quality of the effluent water is excellent and beneficial for use in the reef aquarium. There are many excellent units available on the market today but I have had the most success using one of the SpectraPure units. It produces about 35 gallons per day and includes a prefilter, carbon filtration as well as dionization and post carbon block filtration. This unit produces water of superior quality.
Deionization units use ion exchange resins to achieve the removal of pollutants in the source water. They use two beds of a cation and anion resin to achieve this. Water needs to be flow slowly throughout the beds to allow sufficient contact and maximum removal. Typically, the resins have an indicator resins which change color to signal the user when the unit has been exhausted and needs to be recharged. Recharging is done with two different chemical solutions, after which the resins can be reused although they lose a little of their original potency each time they are recharged.
DI water is also excellent for use in the reef tank. A combination of reverse osmosis and deionization is the process which I prefer as it leads to very high quality water. DI produces no waste water as does RO and therefore it is a more efficient process in that respect but careful monitoring of the effluent is necessary in order to assure a consistent quality of water. After the resins have been used for some time, silicates and phosphates can bleed through and this can lead to an outbreak of micro-algae in the aquarium.
Why is the source water so important? Many hobbyists reason that if tap water is suitable for human consumption, then it must be okay for use on marine organisms. This is a fallacy. Tap water contains many impurities which have been judged to be harmless in certain quantities in humans but corals and marine organisms are usually never exposed to such levels in the wild and their effect never builds up. In aquariums, lethal levels of substances can not only be reached in a short span of time, the effect will also be a cumulative one.
Tap water usually contains chlorine and lead, two things we do not want to accumulate in the tank. Additionally, tap water may contain phosphates and silicates which can lead to micro-algae blooms in the tank, a common problem for many reef keepers. By removing these substances before they mix with the salt mixture we use will go along way to preventing problems in the long run.
Consider carefully whether you need such filtration by testing your tap water or requesting a water report from your local water company. In most cases some sort of filtration will be needed and will be great benefit to you and your aquarium.
In choosing a unit, look for one that has a micron prefilter and carbon block filtration. Pick a unit that will provide you enough water per day as you will need. Do not pick an undersize unit as when you need water in an emergency you will be tempted just to use tap water to save on time. Make sure the company is reputable and will be around to provide customer service and replacement parts such as membranes, prefilters and the carbon blocks.
By now you should have done some reading on reef tanks, chosen a reputable local dealer, chosen the tank and stand, and decided on how you will provide the best quality fresh water you can. In our next installment we will look at the salt mix, filtration components and live rock/live sand. In a few days I will also be posting an article on a behind the scenes tour of the New York Aquarium for Wildlife conservation. We will be interviewing the head biologist for the aquarium, Dr. Dennis Thoney, and will discuss the current research and maintenance procedures of a large public aquarium. We will have lots of pictures so look for it in the next few weeks. See you soon!
Any suggestion or questions are welcome.
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