1. Change 20% of the water every week.
Determine that the fresh water does not contain chlorine and heavy metals, PO4, NO3, Cu... It may affect coral health or make unnecessary algae growth. It is better to use DIfilter to filter fresh water before mixing chemical salts. RO or DI filters can remove chemicals from tap water.
The salt content of new saline water should be between 1.022 and 1.024, keep as stable as possible, and should not change from time to time.
In my personal experience, it is very important to test the pH value every day. The more convenient method is to use an electronic pH meter. (Control at 8.1-8.4)
2. Pay attention to calcium (>350 ppm)
Calcium levels in water are important for hard corals, which themselves will use a lot of calcium to build their bones. Calcium in water will gradually decrease. When calcium falls 350 ppm, it is dangerous. It is preferable to use calcium chloride at 400 ppm.
3. Beware of Ammonia and No2 pollution
A mature aquarium should not have the problem of Amonia. Before putting any coral into the aquarium, you must wait until the Nitrogen-cycle of the aquarium is complete. If you have good quality living stones, I do not recommend using mechanical filters in coral tanks, nor do I recommend using the bottom throat filter method, because the sand bed of coral tanks is difficult to clean.
Easy-to-feed fish (e.g. Sparrows) are first put into tanks to help trigger nitrogen cycling. Some nitrobacterial filters (e.g. Aqua-chargers) have a positive effect on accelerating nitrogen cycling. In addition, taking a little sand from your friend's tank and putting it in the fish tank can also speed up the completion of the N-cycle. This complete nitrogen cycle may take a month or two to six months to complete.
4. Reduce nitrate (No3) pollution (should be kept below 20 ppm)
You need plenty of live stones to circulate with your aquarium, and it may take months for anaerobes to grow.
A good Protein Skimmer.
Avoid overfeeding so that the system is overloaded. Feeding fish once a day is enough.
Intense lighting (recommended metal halogen lamps) helps coral and some beneficial algae grow, which consumes part of nitrate. As for other harmful algae, some algae-eating organisms (such as Phytophthora and Phytophthora) can be raised to solve the problem.
5. Adequate Living Stone and Living Sand
Living stones and sand are natural filtration systems. They can reduce No3, provide hiding space for fish and reduce their sense of oppression.