Light is the key word here. Remember, the newly born nitrobacters that have developed in the final phase of the nitrogen cycling process are an essential part of building your aquarium's biological filter base. These beneficial bacteria live on all surfaces in the aquarium, and as they mature and multiply, they are what keep your system in balance. At this stage you do not want to strip them away and weaken their numbers, so here's what can be done.
- Clean off the inside tank walls.
- Remove any organic waste that has settled on the bottom of the aquarium by lightly siphon cleaning the "surface", and only the "surface" of the substrate.
- Remove organic matter that has accumulated inside and around rock formations. This can be done by either squirting water into these areas using a turkey baster, or simplier yet, use a small powerhead. It's a great way to easily dislodge the gunk that gets trapped, releasing it into the water column where it can then be removed through filtration.
In conjunction with tidying up the system once the ammonia and nitrite levels have dropped to zero, a water change can be performed. In the process of light siphon cleaning up the aquarium, old water is removed, and once done, you refill it with new saltwater.
Doing a 20% to 25% water change at this point is beneficial for the following reasons.
- It replenishes essential sea water trace elements.
- It helps to correct and return changes in pH, alkalinity and other important parameters of the water to their ideal settings.
- It improves the overall quality of the water.
Once the aquarium is cleaned up and refilled, it's time to rinse out or replace any type of mechanical water filtering materials, such as prefilter flosses, cartridges, sponges or pads.
Now let the system run for a few days to allow the filter(s) to polish up the water. If at this point any prefiltering materials appear to be dirty, clean them up again.
- Tip: No water changes should be performed, or any kind of ammonia destroying products added to the water while the tank is cycling, as this only delays and drags out the completion of the cycling process.

