Saltwater changes

[snapper1]

:lol: I have two 55 G saltwater Tanks with predator fish and the second with peaceful Fish.Both have a wetdry and protein skimmer and are heavily populated.I have heard different advice from pet shop owners one says 50 percent water change every month some say 25 percent water change every month.another says 10 percent every month.Need some real good advice and some help please thanx

 

[ChrisRD]

When it comes to fish-only systems, the only real purpose of a water change is nutrient export. Larger water changes are more effective at keeping nutrient problems in check. As for the frequency - it will vary depending on the system . Whatever keeps your nutrient levels at bay is all you need.

With more effective means of export (ie. better skimmer, sandbeds, macro fuge, live rock, etc.) you can strike an import/export balance and basically eliminate nutrient build-up (and thus seriously reduce the need for water changes).

Personally I prefer to run fish-only tanks like a reef system - just without the strong lighting (ie. strong skimmer, live rock/sand, strong circulation, etc.). IME running this way requires very little in the way of water changes for an FO system as there is no build-up of nitrates, nuisance algae (ie. excess phosphates) etc.

HTH