Another 29Gal Biocube Thread

[twicklund]

Greetings all,
Been a long time since i have posted, but here goes.
I have had a 75 gallon reef tank set up for years. I say reef tank, but there is nothing in it right now except the following:

• 
  1 Clown
• 
  1 Engineering Goby
• 
  1 Cardinal Fish
• 
  1 Yellow Tang
  1 Carpet Anemone
  various blue and red shell crabs
  a few Emeralds
  A serpent star (although it's been a while since i have seen him, but every time i think he is gone, he shows back up, so i have not lost hope)

The tank has a sump with refugium and live rock, and a protein skimmer that hasn't been on for a while. All fish and invertebrates are happy and healthy.
As much as this tank has been successful (my clown is 10 years old!) we are redoing our kitchen and this tank must be moved. Because the tank is so old, we have decided to downsize to a smaller, more modern 29 bio cube.
The tang and engineering goby will not be moved to the smaller tank (as much as i hate to get rid of them both, especially the eng goby!)
My plan is to use new live sand, as the sand in the 75 is easily 6 years old, dirty dirty, and bubbly. I'm not sure if it is ok or not to use the old sand, and any advice is appreciated. Is there a suggestion for how much live sand to use? It use to be 4 inches, but it has been so long since i have set up a tank that may have changed???
I will move as much live rock into the tank so that is is aesthetically pleasing and still allow the fish to ample room. I have been told to freshwater dip the live rock, but this is new to me, so any suggestions there are welcome.
Right now, the plan is to use 50% new saltwater mix, and 50% from the established tank.
I will let the tank cycle for the required time (i know how to test and make the decision when levels drop back down) but hopefully there won't be much of a cycle due to the reuse of water and rock.
The bio cube comes with bio balls, i plan to take them out. Should i replace them with live rock? Leave them? I am really worried about this area.
I bought the bio cube skimmer, should i put that in from the start?
Ok, i guess that's enough rambling for a bit. Thanks in advance for any advice, and i will post pictures as the tank progresses.
Thanks again!

 

[saxman]

Adding "used" water will only add NO3 and whatever other pollutants that may have built up over time. The bacteria you're hoping to colonize the new tanik with are NOT found in the water column, but rather on and in the LR, LS, and any biofiltration media you're running (sponges, bioballs, ceramic tubes, etc.). Any pre-existing NO3 will also make it harder to determine if the new setup is cycled, as when the NO3's come up, it means your tank is processing both NH3 and NO2.
As for the used substrate, you can re-use it, but if you'll want to completely rinse it till it runs clean with either SW (to maintain part of the bacterial count) or use lots and lots of FW, again till the water runs clean.
As for LR, if you're worried about possible harmful hitchhikers, don't use FW, as it will kill of the bacteria on the rock. A better solution is to give the LR a hypersalinity bath in a bucket or tub. Mix the water to 1.040 and dip the rock for about 10 mins. If you use a white container, it's easier to sort thru the critters that come out of the rock, so you can add any "goodies" back to your DT.
I recommend LR over bioballs anytime.
You don't need to skim the tank while it's cycling...it's counterproductive.
HTH