Water Volume

sil40sx · Apr 13, 2016

Ok, this might not make sense (or maybe a dumb question), but I will try my best to explain/ask.

Say for example a 40g tank, doing a water change of 50% (20g), I've heard/read that this amount is still ok with livestock's because its a good way of exporting nutrients... But, is this the same thing as adding 40g on top of the existing 40g (50% new, and 50% old water)?

Let me elaborate more clearly. LOL - The reason I'm asking this, is because I may have a new tank this weekend if everything goes smoothly. My plan is to transfer all Live rocks and water from old 40g tank to the new 75g tank, then just add new salt water to top it off . I guess my main question is, would the parameters still be stable as a 50% water change, or will it create a mini cycle?

Thanks in advance!

ElectrumGuy · Apr 13, 2016

Bacteria would still be there so I don't see why not?

sil40sx · Apr 13, 2016

ElectrumGuy said:
Bacteria would still be there so I don't see why not?

That's what I'm hoping too, because that seems to be logical. But one of the things that I've learned in this hobby even in just a short period of time, is things that might appear to be simple, ain't simple at all, there's always a catch 22. That's why I want to ask around here before I make a move, to be on the safe side.

sil40sx · Apr 14, 2016

Bump!!!

Aaron4890 · Apr 14, 2016

From my understanding the bacteria is in the live rock and sand bed. You should be able to use 100% new salt water and just acclimate any fish or invertebrates to the new tank. Your live rock is already established so you should not have any problems that I can see of.

cmcoker · Apr 14, 2016

How long has the 40g been setup?
It should be fine, even with all new saltwater. I would have more saltwater on hand than you think you need.
Use some old saltwater to swish the rock in before moving to the new tank.
Remove livestock before disturbing the sand bed.
Are you planning to reuse the sand or new sand?
Biggest thing to avoid cycle in tank breakdown is removing detritus, not moving it into the new setup.
@brandon429 has some good links/info

sil40sx · Apr 14, 2016

Aaron4890 said:
From my understanding the bacteria is in the live rock and sand bed. You should be able to use 100% new salt water and just acclimate any fish or invertebrates to the new tank. Your live rock is already established so you should not have any problems that I can see of.

I hope so. Thanks.

cmcoker said:
How long has the 40g been setup?
It should be fine, even with all new saltwater. I would have more saltwater on hand than you think you need.
Use some old saltwater to swish the rock in before moving to the new tank.
Remove livestock before disturbing the sand bed.
Are you planning to reuse the sand or new sand?
Biggest thing to avoid cycle in tank breakdown is removing detritus, not moving it into the new setup.
@brandon429 has some good links/info

Just a little over 3 months... My plan is:

1. Transfer all water from old to new tank
2. Fill new salt water to top it off
3. Transfer all live rocks and all livestock
4. Wash the sand thoroughly and repeatedly with RO water until water is clear
5. Add the clean sand gradually each day (approximately 1-2 pounds a day?) to avoid mini cycle
6. Keep using my canister for a few days, or maybe a few weeks and gradually remove media's (sponges, GFO, and Carbon) until canister is empty.

Will I be safe doing these steps?

cmcoker · Apr 14, 2016

sil40sx said:
I hope so. Thanks.

Just a little over 3 months... My plan is:

1. Transfer all water from old to new tank
2. Fill new salt water to top it off
3. Transfer all live rocks and all livestock
4. Wash the sand thoroughly and repeatedly with RO water until water is clear
5. Add the clean sand gradually each day (approximately 1-2 pounds a day?) to avoid mini cycle
6. Keep using my canister for a few days, or maybe a few weeks and gradually remove media's (sponges, GFO, and Carbon) until canister is empty.

Will I be safe doing these steps?

Tank is pretty young, how much livestock do you have?

I would swap the order of 2 and 3, meaning move you live rock over before you topoff new saltwater. At least don't fill the tank to the brim, the rock is going to displace some water and it may overflow.
Do a final rinse of the sand with saltwater.
I would add the sand back all at once when you put the tank back together. how do plan to store with slowly adding it back. I'd be concerned that storage would allow it to become stagnant and cause the cycle you are trying to avoid.

An ammonia badge and a bottle of prime are cheap insurance to have on hand but I think you'll be fine.

I just reset my biocube 14 after a year of neglect, I rinsed the sand bed in the tank with a hose till it ran clear, then a saltwater rinse before replacing rock, soft corals and snails and hermit crabs. Fish were being moved to a larger tank anyway. I saw no cycle and moved a goby/shrimp combo from my 5g into the biocube after a couple days, still no cycle.