Wet-Dry in a reef tank

[johnstringer]

I was thinking about setting up a small wetdry unit I have on my 55 gallon, but instead of bio-balls, using crushed coral as the media. Would this help improve Ca levels and alk.? Would I have the same drawbacks from the W/D as I would if I was using bio-balls ?

[Wzrdbear]

You might have a small benefit of calcium being "tumbled" off the media, but you still will have the negative effects of balls. The extra ca is small so not worth the trade off. Just leave it out...If you have good rock and good sand and a well balanced ecosystem (as well as possible anyway) it'll work great. You will have to dose kalk or ca though.

[G-money]

To get any significant Alk and Ca maintenance from crushed coral, you need to use a calcium reactor-like depressed pH environment. The amount of Ca and Alk released from aragonite at normal reef pH is negligible.

Also, I would suggest allowing your live rock and sand to do the filtering for you. Wet dry filters are overefficient in that they reduce NH4 and NO2 to NO3 so quickly that NO3 builds up to higher than desirable levels before in can be degraded by anaerobic bacteria. Ample rock and sand can easily handle Ammonia and Nitrite levels in a reasonably stocked tank at a more natural pace for the system...

[johnstringer]

Thanks for the feedback. I have been dosing Kalk, but read about decreased Mg levels from doing that, and have recently switched to a different product for Ca additions. I was hoping the CC in the wet/dry might provide a more natural way to increase Ca, but I guess not.