Water Change Question

[Shep]

Hey,

I have been wondering if you can change your water too often? I have a 20g tank with a 3.7g refugium, I do not have a skimmer so I do water changes once a week and I change out about 4g when I do them. Is this ok or am I overdoing it and should I cut back?

 

[Randy Holmes-Farley]

The question depends on the goals of the water change, the quality of the new salt water, and the way in which it is changed.

You are changing out about 20% a week. That is certainly on the high side, but not too high if you are careful about how you do it (matching salinity, temperature, etc.).

I would not be concerned about excessive removal of things you may want in the water, because the salt mix likely has those already.

The only limitation that I'm really aware of doing frequent water changes is bringing in trace metals that in some aquaria might be limiting to things like cyanobacteria. Unless you have that issue, I wouldn't consider that an important factor, and it is far from proven to be a general phenomenon.

 

[mike007]

I have found that a 10% water change a month works great for me. If you are adding any trace elements and do excessive water changes you could possibly get a abundance of nutrients which can fuel algae growth. Small water changes as we have all believed to reduce nutrients really don't accomplish that much. Better to export nutrients by other means in my opinion.