Moving to a larger tank

[stefdvm]

I'm trying to figure out the best way to accomplish this - basically what is safest, least stressful for my livestock. I have live rock and some critters in the current aquarium; the new aquarium is 3x the size of the old one, so even if I move the existing water, I'll have to add about 80 gallons of new water. Last move I made was from tanks of equivalent size and I just literally moved everything - rocks, sand, water and livestock - over the same day and it was fine. I don't really know how to go about this since I'm adding new water and substrate.

I figured I'd put in some new water (maybe 40 gallons or so) and rocks into the larger aquarium - all of the new (dead) rocks and some of the old maybe? - and then the new sand and let that settle out before moving any fish, but if I transfer all of the existing water, and the live rock, will the new aquarium then be safe for my fish or do I need the new tank to run for a period of time before moving everyone / everything. Do I even need to transfer the existing water? Is there a benefit to that?

Lastly, should I transfer the old sand? It's not terribly "old" - 12-15 months - I've had differing opinions on it. Some say yes move it because it has beneficial bacteria in it, others say no because it's basically a detritus sink. Anyway, we're building the stand next weekend so the move is approaching but still several weeks off, so I thought I'd try to get some advice before it becomes imminent.

[first29gallon]

I have the same questions you have stefdvm. I just started my 29 gallon tank and I am pretty sure I am going to move in 6 months and getting a bigger tank when I do. I guess the your situation will be mine then but I do think about it. Here are my thoughts and I have no experience so take it for what it is... First, you want to cycle the new tank. I assume you will use RODI water. I would cycle 40 gallons worth for as long as it takes as if you were cycling any other new tank. You can use live rock or dry rock and sand but the dry rock will take longer to cycle. After its done cycling, go ahead and move over everything from your old tank including sand, rock and water. If you are going to wash anything that is going to be going in the new tank, do it only with the old tank water. Vacuuming the sand it fine. Make sure the water temperature and other parameters are the same.

After you have the old 40 mixed with the new 40, keep it going like this for a couple of weeks. Then make a new batch of 40 gallons and just heat it up this time. no need to cycle this last 40 gallons since its just water. Go ahead and add the 40 to the 80 and you're all set. Again. please note that I have never done this.

[tomreefer]

I would not use the same sand just take a bout a cup of two of your old sand to seed it. Your liverock will be mostly your bacteria.. Should have a small cycle to none. If you have any sponges make sure you scrape them off. Sponges can't live out of water

[Sapelo]

Alright, here's what worked (and didn't) for me:
This summer we moved a 90 gallon to a 300 gallon. We used all new sand for the 300 and new water (if you're keeping a tank, water is one of the cheaper things you have so why not go for fresh and clean? It's not like old water will do much (anything) to help your cycle anyway.
I did have the advantage of quiet a bit of "extra" live rock that I could transfer into the 300 without decimating the 90. I used all of the cured rock from the previous 300 setup and stole some rock initially from the 90 so that I could go ahead and work my aquascaping without having to redo once the fish were transferred.
The tank ran for 3 weeks with CUC but no fish due more to the fact that I was working out some plumbing and equipment issues. During this time, no cycle was observed.
I then transferred the fish and coral from the 90.
I had no fish or coral losses but did later experience a bit of a cycle and am still working to overcome a bit of cyano on the sand.
I'm sure others have done a better job, but these were the choices I made with no realy disastrous results (other than the cyano which I really, really HATE).
Good luck! Bigger tanks are always so much fun!

[Sandnukka15]

When u transfer everything I would use stability to help with the mini cycle

[stefdvm]

Thanks for the input!! I suppose there's no reason to transfer the water in hindsight... I have a good amount of live rock (about 60#) and then another 75# of dead rock so I can put in about half the live with the dead and let that "cycle" for a while. If I'm not transferring the water, then there's no real rush with regards to the fish; I can grab a cup or 2 of sand to "seed" the new sand, and give the new tank a few weeks; I do have some of the Dr. Tim's which I've seen good reviews on- not that I'd just dump it in and pop in a fish - I'm a little too cautious for that - but it's supposed to help minimize the initial cycling time.

My new dead rock is really clean - should I still "cure" it in a trash can? (bought a brand new one just for that in case it was advised); salt water, heater, airstones, powerhead? Is that necessary since there appears to be no organic material on it? Or can I just soak it in salt water or RODI water and scrub it with a new brush?

[Sandnukka15]

I'm not an expert but Imo... I would just add the rock as is if your going to wait a few weeks for the tank to cycle and adding Dr Tim's..... just keep checking ur perams

[gone fishin]

After I moved here I set up my 29g to have a something to look at while I got my 180g back up and running. After many long months I finally had the 180g filled and ready to go. I simply moved the rock over from the 29g then moved all the critters over. Since I QT all my fishes I was not to concerned about increasing the bio-load to quickly. Good luck just my 2 cents.