Need a little (lot) more info to advise properly. For example are you using
Live Rock? DSB? What Skimmer? Size of tank? etc

As general rules....if using live rock, make sure the structure is fairly
open with good circulation in/around. When I had a substantial nitrate
problem upping the circulationa around/through the rock was enough to sort
it. Clean your skimmer regularly. Think about your feeding/maintainance
regimens....is there a reason for the nitrates? What water are you using
for top up/water changes.....have you checked that you are not putting
nitrates into your tank?

There is no reason, with a bit of forethought, not to be able to manage the
nitrates. Water changes can help, but don't get to the root of why the
nitrates are there.

"swhastan" wrote in message
...
Hi, guys
I have a few corals in my aquarium.(Xenia, Zoo, Elegant coral, and
anemones)
Current nitrate level is around 10 ppm. Also, is this level of nitrate
really dangerous for my corals and anemone?
Also, I'm trying to reduce it with macro algae such as caulerpa in a 29 G
refugium, and denitrate matrix rock in power filter. Can I just wait for
low
nitrate level without water change?
Is water change is the only way to reduce it in a short time?

Thank you for reading.
Sungwon