upgrading tank please advise


New member
Well this weekend I am trading in my 90 for a 125. I'm curious about peoples experience with moving all their inhabitants from one tank to another. How much water should I keep from the old tank? Is there going to be a huge spike from stirring up the live sand? I have about 60 gallons or so of ro/di water ready to go. I am also going to be adding some live sand from a friends tank to make up the difference to fill my new tank. Are there any more concerns I should have, or what else I should be doing? Thank you in advance.
If you are moving the sand from one tank to another I suspect you will have a cycle and some dirty water for a few days. How long has the tank been up that you are taking down?

It appears to me that you will have to keep some water from the old tank as you don't have enough new to fill the 125.

What kind of critters do you have to move over?

Based on the amount of new water you are putting in I would guess that you will have to acclimate them as if they were new inhabitants.

I went from a 46 bow to a 90 but I used all new sand. The only thing that came from the 46 was the fish, snails crabs etc and the live rock.

You don't mention live rock. How much is in the 90?


I have a few different fish, regal tang, a couple of gobies, clown, rabbit fish. The usual clean up crew, snails blue leg hermits, one urchin, emerald cab. A couple of shrimp. various corals mostly soft, one encrusting on my LR. I have about a 100lbs of LR. The tank has been set up for just over a year.
I went from a 60G to a 180G. I used a few cups of the old sand to seed (top layer only) and added 150+ lbs of play sand. I also used 30G of water from the old tank as well. Added about 150+ lbs of base rock and tossed about 5-6lbs LR from the old tank to start it. I waited about 2 weeks w/ a couple of hermits (test it) in the tank and tossed some pellets every third day.

After the 2nd week (after testing every other day), I went ahead and did a complete move of all the inhabitants. I also switched out another 30G of water from the old tank on this 2nd move as well. I have mostly SPS & clams and everything went great! None of my 6 fishes, fire shrimp, serpent star, snails or hermits were lost. SPS and clams were fine as well with no signs of stress.

Although, I did ensure that PH, temp & salinity were all relatively same.


Thank you. The only problem is I don't have that luxury of waiting. I am going to be trading my tank for the 125, and the swap is going to be happening the same day. I do not have any place to keep my livestock while the new tank sits. Any more advice out there?
I did my waiting just because I could but could have done it in a day if needed I think. I've done it before on a move but it was from a 60G to 60G.

I would then suggest using 75-90% of the water from the old tank for precaution (but not too much from the cloudy bottom portion) and filling in the rest with a new batch of saltwater (mixed a day or two before w/ powerhead/airation and match salinity/heat) but only using a few cups of the old sand (you don't want the stuff that's been building up in it - toxic). The rest of the sand should be new me thinks. Make sure the temp and PH are the same and you should be okay.

Another suggestion would be to get a rubbermaid bucket/container and have your livestock in holding until everything's settled in the new tank (put a temp. light fixture if needed as well for any inverts).


I unfortunately only have the one day, as the tank I am using currently is being traded to the person who is giving me the 125. I bought new play sand(first time I've tried this) to make up the difference in the new tank. The sand I have now is all live sand. I have about a 2 in sand bed in my 90 of the stuff. I do have about 60 gallons of ro/di water all made up in trash cans now. Perhaps I should use all the water I can from the 90 before it clouds up. I am concerned about the live sand I currently have. I would like to keep it as it has lots of goodies in it, however I am fearful of a huge spike. Do you think the difference in water volume would counter this "spike" enough?