Water must first be prepared in advance of the change day. Some type of storage vessel will be required. A food grade trash can is my preferred choice. I also keep a set of casters on it to roll it around easily. If municipal water is used, it must first be treated with a dechlorinater. If you have well water or use Reverse osmosis, then this treatment is not required. I keep my barrel next to an electrical outlet and have a submersible heater and power head running in it. If a large pump is used, it may throw off a lot of heat so check that out before you add heat unnecessarily. Circulation of the water is important for several reasons. First of all , you don’t want your water to become stagnant. Water left to sit often develops an unpleasant odor and is not recommended for use in your delicate aquarium. Sea water needs to be thoroughly mixed for some time to avoid fluctuations in pH, salinity and temperature. You want to try to match up the change water with the existing parameters in your aquarium.

Stable specific gravity and pH are essential in reducing stress and easing the strain on the osmoregulatory processes. Many the aquarist believes that toping off evaporative loss with fresh water is a water change. While it does provide some relief in the form of reducing the elevated salinity back to normal, it doesn’t replenish any of the trace elements that the organisms need to thrive. Trace elements constantly need to be replenished because they become naturally exhausted. Organisms in the eco-system use them up or many become chemically bound up and un-usable. Some portion of the aquarium water must be drained off and replaced with fresh pre-mixed water.

The siphoning off of water in and of itself affords the aquarist a second good reason to perform the chore. It’s a perfect opportunity to remove unwanted detritus from the bottom of the tank and off of the liverock. I’m a true believer in allowing your tank to breath and if detritus is left to build up, it can open you up to problems with algae and oxygen diffincies. Some creatures burrow through liverock and leave behind powdery rubble witch must also be siphoned out. Start by toping off the tank to it’s proper level with freshwater so your specific gravity is where it belongs before you begin. If some has evaporated and you don’t compensate with your mix, your salinity will be off at the end of your chore. Be sure to snake your hose up in those tiny cracks where detritus accumulates. If you employ the use of a powerhead in the tank, there is a good chance that everything congregates in one or two dead spots. This makes for quick clean up. After removing 5 or 10% of the aquarium water, replenish it with your premixed water.

While many aquarists run reef tanks with little or no water changes and do have some degree of success don’t recommend that it be done. Every aquarium benefits from regular partial changes. For the animals to truly thrive they must have their recourses replenished on a regular basis. We don’t want our animals to simply survive. We want them to thrive and hopefully reproduce. This can only be achieved by providing the best possible habitat we can. Regular changing of water in conjunction with wet/dry trickle filtration and an effective protein skimmer will go a long way In achieving success with your reef aquarium. If you are keeping a fish only setup with no live rock then the necessity of water changing becomes even more immediate.

If ease of maintenance is your goal, then a dosing pump could be the answer to your dreams. They are simple two cylinder pumps that run in sequence with each other. One side draws a drop of water out of the aquarium while the other side replenishes a drop of pre-mixed, heated and circulated water from your storage vessel. The stroke rate must be adjusted to operate in sequence. This is a simple adjustment and once you get the swing of it the system can operate continuously. This certainly is a healthy way to go but can get to be expensive. You will go through a lot of salt. The system could be primed and ready to go and only used one or two weeks out of the month. Gradual changes are best. The animals don’t tolerate large fluctuations in their environment well.