Upgrade Size Rule of Thumb?

[hockeyhead019]

Hey everybody, I'm curious if this has been talked about before. My searches didn't yield much in terms of a rule of thumb, more so specific examples and what went right/wrong.

Is there a rule of thumb along the lines of: if you increase volume by XXX then you're more likely to have a mini/full cycle?

I'm looking to go from my 20g mixed reef to an upgraded 75g tank. I'm aware there are some details which greatly matter in this conversation, live rock vs dry, BB additive vs not. I'll clarify that my 75 will just have dry rock added to get the total rock up to where I want it, and all new sand will be added (coarser stuff so I can vacuum easier). Do you think I'll run into any mini cycling issues? I can't forsee why I would but wanted to reach out and ask.

 

[Smite]

Hey everybody, I'm curious if this has been talked about before. My searches didn't yield much in terms of a rule of thumb, more so specific examples and what went right/wrong.

Is there a rule of thumb along the lines of: if you increase volume by XXX then you're more likely to have a mini/full cycle?

I'm looking to go from my 20g mixed reef to an upgraded 75g tank. I'm aware there are some details which greatly matter in this conversation, live rock vs dry, BB additive vs not. I'll clarify that my 75 will just have dry rock added to get the total rock up to where I want it, and all new sand will be added (coarser stuff so I can vacuum easier). Do you think I'll run into any mini cycling issues? I can't forsee why I would but wanted to reach out and ask.

If you mean Marco mined rock I think you’ll be okay. That’s pretty clean rock. I would still add bacteria of some kind, better yet pre soak the Marco rock in the bacteria overnight of possible to seed it well.

 

[Bryan68]

I went from a 43 gallon to a 180 gallon. Used my live rock from my 43 and another 100ish pounds of marco rock. All new dry sand plus one cup of live sand from the 43 gallon. Added some bacteria in a bottle. Did not get a cycle.

 

[ca1ore]

Whether you will have a cycle of not really has very little to do with just adding volume. If you take the rocks and animals out of a 50 gallon system and put them into a 200 gallons system the bioload remains the same. Loss of bacteria in the old sand will be a factor, but IME not a major one. If you used the change to add a bunch more fish then, yes, you would potentially stress the capacity of the existing biofilter and likely see some ammonia.

 

[hockeyhead019]

Whether you will have a cycle of not really has very little to do with just adding volume. If you take the rocks and animals out of a 50 gallon system and put them into a 200 gallons system the bioload remains the same. Loss of bacteria in the old sand will be a factor, but IME not a major one. If you used the change to add a bunch more fish then, yes, you would potentially stress the capacity of the existing biofilter and likely see some ammonia.

This was my understanding but I wasn't sure if the extra space would thin things out and result in a small die off or something along those lines. But that makes sense, bacteria feeds off of the bio load, if that doesn't change then water volume shouldn't really matter.

 

[terraincognita]

Whether you will have a cycle of not really has very little to do with just adding volume. If you take the rocks and animals out of a 50 gallon system and put them into a 200 gallons system the bioload remains the same. Loss of bacteria in the old sand will be a factor, but IME not a major one. If you used the change to add a bunch more fish then, yes, you would potentially stress the capacity of the existing biofilter and likely see some ammonia.

+1 exactly

 

[homer1475]

As long as your not immediately increasing the bioload, the move is a lateral one.

Think of it this way......

If I had a biocube fully stocked and it was doing well, I then decided I wanted to add a sump of 150G, your just increasing the water volume, not the bioload.

 

[terraincognita]

Important is to not increase your bio load for a bit.

And don’t feed more either because it’s a bigger tank! You still have the same inhabitants.

If you went from a 20G to a 150G and changed the bio load too quick you’d most likely definitely at least go through another uglies stage but not necessarily a cycle.

Just do the transfer and let it build for a month or so.

 

[ScottB]

The more bacteria coated material you can bring over, the better. I don't think you'll suffer a cycle. Just don't dump 20 fish in at one go. The rock will go through the "uglies" though.

I will point out one common risk you might want to account for. I will build it up for you:
a) So you are going to have all this new, sterile surface area. Glass, rock, plumbing, sump etc. No film algae, no bacterial film. No microfauna...
b) All that new rock (if Marco) has zero phosphate buffered in it. It is going to suck up any available phosphate.
c) I am not all against dosing some bacteria, but be aware that the bacteria will be consuming the ammonia, PO4 and NO3.
d) Whatever nutrient is in the existing water will be diluted significantly by new water volume.

a + b + c + d = potential dinoflagellate outbreak

I would strongly consider dosing up the new tank with PO4 and NO3. It will take A LOT of phosphate solution as it will be getting bound up in the new rock almost as fast as you dump it in. This will help get some film algae going to compete with the dinoflagellates. You might be slightly accelerating the uglies, but you gotta go through that anyway.

I went through this twice while building out my frag system. Each time I hooked up a "new" tank I would get hit with dinos. I went through a liter or more of phosphate each time to get back on top. I should have done that preemptively.

 

[hockeyhead019]

Thanks for all the responses!

Sounds like the typical reefing advice of "go slow" is especially relative here. Build the bio load slow and let everything keep up as need.

This is about what I expected but wanted to make sure I wasn't missing any pieces.

 

[MichaelReefer]

I think its all variable. I went from a Reefer 250 to a Reefer 525XL. I did not get a cycle but I did get bad Cyano and hair algae for a few months. Faded away though.

 

[mcshams]

We combined our 40gallon nem cube and a 90 gallon tank into our 200g peninsula. All the same rock (we added about 60 lbs), kept all the existing sump media as well. As @ca1ore pointed out, there really is not a reason to expect a 'cycle' just due to an increase in volume. The beneficial bacteria is substrate-bound. While you are missing the sand, it's typically not enough of a bacterial loss to change things providing you don't rapidly fill your new larger tank with inhabitants.