How often should I do a 10% water change for my LPS tank?

[doby]

My LPS tank only have torch and hammer corals. I have been measuring my water parameters with Red Sea FOUNDATION PRO Multi Test Kit and it seems that my Cal, Mg and Alk level do not change much after 1 week. So question is does it still make sense to change water every week?

[DottyClown]

To me, water changes are for 2 main purpose. Replenish trace elements and export nutrients. If your water parameters are all within range, then technically there is no need to change water. I have heard of many reefers not changing water for months. They monitor their water closely, dose if needed, nutrients are exported sufficiently, thus don’t find no need to change.