Replacing My Tank

[rjjr1963]

I want to replace my tank but this time I'll have it drilled so I can use a shadow overflow.

The tank is a year old and really doing well. I don't want to mess that up. I could do the transition in about 4 hours. I can save about 35 gallons of old water in my mixing station. Live rock, fish and corals will go in 5 gal buckets.

If I replace the gravel will this cause a mini-cycle? The gravel is pretty clean as I vacuum it when I do water changes. I'm wondering if there are a lot of good things growing in the gravel that I would want to keep to maintain as much stability as possible.

All comments and suggestions welcome.

[mcgyvr]

Replacing the substrate will not cause another cycle..
Sufficient bacteria should already be present all over the live rock.

Really no point in using old water IMO.. Little bacteria is free floating in the water..
You can transfer some of the "gravel" (are you really using gravel vs sand?) to transfer some of the microfauna living in it but the rock should also have some to kickstart the new tanks population..

[rjjr1963]

Only reason I thought about using the old water was to maintain the chemistry. Nutrient levels etc... Maybe it's not worth the effort.

[mcgyvr]

Only reason I thought about using the old water was to maintain the chemistry. Nutrient levels etc... Maybe it's not worth the effort.

In general new water is the "best starting point"..

[DesertReefT4r]

Depends on your water quality. If your water is in check and has low nutrients there is no reason not to use it. If your cal or mag is way off or you no3 or po4 is high then all new water will be better. There is also no harm in using your old sand, you can replace it if you want but I would save a good amount to seed the new sand. Expect your corals to have at least some negative effects from a tank transfer, color loss, poor PE, browning and in worse cases STN/RTN or coral loses. I always just expect to loose some corals in a move or transfer so if I do has loses Im not upset about it but that is not always the case. Lastly take your time and give yourself all day to do the tranfer, it will take longer than you think even if you planned it out well. Call a friend over for help, buy pizza and beers helps a lot.

[thegrun]

I personally prefer to use as much clean water as possible from my old tank when switching tanks (assuming your water parameters are good and your nutrients are low) exactly for the reason you gave, trying yo keep the same water chemistry in the new tank as close as possible to your old tank. On a side note it took me 8 hours to relocate my 120, but I had a lot of delicate stony corals I was trying to protect. 4 hours may be overly optimistic (or I'm just slow!).