[dattack]

Just wondering.

I have a system that probably had one water change in the last 6 months. My tank, IMO, looks pretty decent and I haven't lost a coral except for the time my sump got flooded and power got shut off.

I always thought the Alk and Ca were the only thing that requires adjustment in terms of keeping hard corals/clams. If one were to run a nice refugium, DSB, and a quality skimmer, is water changes going to be really needed?

I saw a small number of reefers in my area that haven't done a water change in 1-2 years and their coral looks magnificent.

I advocate water changes if the system is not keeping up with the bioload but with the setup I have the nitrates have been nonexistent.

??

[Tank]

I don't do them. Very light bio-load DSB 5-6 inches around 90 lbs of LR in a 75 Gal tank. Only like 40 Lbs in display tank 50Lbs in refugium.

[reefer504]

The only time I do a water changes is if somthing does test right.Which has only happened twice in the past year.

[Reefland]

I performed them infrequently on my last tank and ended up with a huge nutrient problem that I had to fight off. I too had plenty of LR and LS, along with a refugium utilizing grape caulerpa for additional exporting means. I enountered a high nitrate level until I started performing water changes in my maintenace routine.

Just my experience,
Scott Z.

[dattack]

How often do you water changes Scott?

I am tempted to start up again on the water changes considering I really don't know what the benefits are other than maintain some Ca levels and of course decrease nutrients.

If my parameters are low at this point, it still acts as a nutrient sink? Or in time, does the tank become more unstable?

[Reefland]

I don't at all right now!

I was and will do them bi weekly, changing 10% of the display volume; mainly to dilute nutrients. I'm going to stab in the dark and say that there may also be a concern with other types of long term build up; metals particularly; Maybe even herbicides and insecticides? However, this would be less of a concern using RO/DI water, but still soemthing to ponder.

Once my new tnak is running, I will revert to my bi weekly changes. They were successful for me!

Scott Z.

[Steve]

I do them infrequently and need to do them more on a regular basis. I do not run a protein skimmer and the water sure does get yellow after a while! Of course, the only way to tell this is when you are doing a water change and the waste water is going into a white bucket.