Advice needed, 55 to 90 gallon upgrade


New member
So I'm preparing to move everything over from my 4 year old 55 gallon to a new 90 gallon system.

The 90 is rigged, freshwater tested and ready to go. My question is about adding additional rock and substrate.

I have approx. 80lbs of live substrate and 60lbs of rock in the 55g. I won't be adding any new livestock to the 90g for a while after it is set up.

Can I get away with adding 40lbs more non-live substrate and 40lbs more "dead" rock when I set up the 90g?
She's a Berlin style reef with a refugium.


Reef Addict
As for the non-live substrate... you need to be careful not to trap any detritus after the transfer. I would clean the old substrate and add it to the top of the new substrate.
I don't really know what you mean by "dead" rock. If it is man made there is going to be a cycle for this rock. I would try to add some "cured" LR in instead.
No matter which way you go there is going to be a mini cycle. I added 40lbs of Dry Aragonite to my BB tank and there was a small cycle.
For the cycle you could try using something like Dr. Tims Nitrifying Bacteria. It has good reviews.

If it were me I would use the 55 as a holding tank for the fish, coral and inverts as the 90g setup goes through its cycle. Just my 02 cents.


New member
No man made rock. Probably just dried old live rock. Haven't really decided on that part yet but nothing man made or mined.

Reverend Reefer

New member
just seed the dry rock with some live rock from your current tank and it'll be fine. you can do the same with your sand, just take a couple cups of your live sand from your current tank and seed the 'dead' sand. just choose a reef safe good 'dead' substrate and good porous and lightweight 'dead' rock.

+1 on being careful with your old sand. rinse it well. you'll know you need to rinse it because once you turn it all up it will likely stink!


New member
Obviously I will need to rinse with saltwater. That sounds like a lot of water though. How could I handle that? Just make up a lot of new saltwater?


When I did my upgrade, I kept the old tank awhile for my livestock while the new one cycled. I considered keeping the old sand, but figured it was too much trouble.

I seeded the new tank w/ some live sand & rock, & dosed w ammonia for awhile. After cycle was done I added in the rest of my live rock & livestock. I had no deaths.