switching substrates

You will have to remove the UGF if you move to sand. If you have adeqaute live rock, the sand and rock will be enough filtration for a tank, as long as you don't overstock. Much less maintenance too--no vaccuming!

When I swapped out mine, I pulled everything from the tank, put fish, rock and corals in a tank, pulled the CC, put in the sand, slowly refilled with new SW, brought it to temp, and put everything back in. No spikes, no losses. Took most of one day to do the 65.

Edit: forgot to mention--I kept the top inch of the CC, put it in nylon bags, and kept them in the tank for about 2 weeks, to allow the beneficial bacteria to migrate to the sand. Probably wasn't necessary, with the 80+ pounds of rock, but it didn't hurt and gave me a safety blanket.

Hey, I just did this.

I set up a receiving aquarium (50 gallon catching from a 125) filled with half new and half old water, transferred about a fourth of my CC to the receiving aquarium (to maintain detrivore population) and let the dust settle. When the water cleared, I moved (in this order) live rock, sponge colonies, dead rock, fish.

No losses; the fish were happy and hungry the next morning. Even the sponge, which has been finicky in previous moves, did alright. It may be important to note that nothing, not even the substrate, was exposed to air in the move.

Stripped the old aquarium to the back to the bottom glass. Boy what a mess :sick: If nothing else would convince me that UGF's and reefkeeping don't go together, the slop I pulled out of the bottom of that tank did the trick.

I pre-cultured the sand (using some of the CC to "seed" it per OrionGirls advice) for a DSB before I refilled the 125, but that may have been unnecessary, because (compulsive that I am) I re-cultured the sand after I laid down the new substrate. Last night, I "fed" the tank 10 - 15 cc's of liquid ammonia, this afternoon the ammonia reading was zero.

To anwer questions, rather than detail my little drama:

Sandbed and UGF don't mix, but a DSB makes the UGF unnecessary.

Corals and UGF don't mix IMHO, but DSB works fine for either fish-only or corals/inverts.

Fish stress can be minimized (virtually eliminated, except for the actual capture) by setting up a temporary aquarium.

Sorry for the long post, I get wordy talking about my science-projects