Old filter, new sump & D/T... How do bacteria migrate? When can I disconnect?

[zeusfc]

Hi all,
Interesting dilemma...

I've got a new d/t with sump; usual sort of thing, sock, skimmer, 'fuge etc, but I've presently got the old DSB & live rock in a tank out in the basement, connected into the system...

Thing is, I'd really like to close it down; it's now been running about nine years, and the basement is not too stable temperature wise, so it's not economical to leave it running out there...

I've added 20lb of live sand to the D/T, and 10lbs of miracle mud to the sump, and the about 30lbs of D/T rock.
I've left a space for a few lbs of siporax, so I'll be adding that too, as soon as I've given it the micro' treatment...

The DSB was big for the old tank; about 50lbs of sand, which has kept my tank nice and stable for years, but...

Like I say... It's got to go at some point, so how do I judge when it is no longer needed? Obviously any water readings will be pretty much the same for anywhere in the system...

I'm sure there's a way to work this out, other than just disconnect and hope for the best!

[bertoni]

I suspect you can just disconnect it. I might stop feeding for a few days, to limit the filtration load, but the system likely will adjust. How big is the display, and how much live rock is in the rest of the system? You could leave some circulation running in the old tank so you can reconnect it if needed.

[Bogue Chitto]

If you don't have a big fish load you will probably be o.k. as bertoni says.

[BrianKC]

Why not phase it out just like if the DSB was in the DT? Remove 1/3 at a time until it's just a tank of water, then disconnect?

[zeusfc]

Why not phase it out just like if the DSB was in the DT? Remove 1/3 at a time until it's just a tank of water, then disconnect?


Forgot to say... It's a Jaubert plenum DSB...so I'm not certain if I can do it a third at a time, as all the "nasty" below the mesh will escape back into the tank.

The DSB tank is 24" X 18" X 18" ( sand is about 6" deep) the display tank is 36" X 20" X 20"

[BrianKC]

Ahhhh. Yeah, disregard then.

[bertoni]

Hmm, I suspect the tank will be okay if you remove the plenum, but I'd have some Amquel on hand, and water for changes.

[Dan_P]

Are you saying that you have a new system connected to an old system and that you have transferred all your old system creatures to the new system?

[zeusfc]

Are you saying that you have a new system connected to an old system and that you have transferred all your old system creatures to the new system?


That's exactly it... Well, livestock is all moved, but with minimum rock, due to glass anemones in the old D/T. I used new dry rock, and a load of (anemone free) old stuff has been left in the old RDSB tank which is connected to the new system, by a 600lph pump, and overflow... I will still use it, but It's the timing of disconnecting the old sand bed that I have no idea of; how do you know when enough bacteria has migrated?

[Dan_P]

That's exactly it... Well, livestock is all moved, but with minimum rock, due to glass anemones in the old D/T. I used new dry rock, and a load of (anemone free) old stuff has been left in the old RDSB tank which is connected to the new system, by a 600lph pump, and overflow... I will still use it, but It's the timing of disconnecting the old sand bed that I have no idea of; how do you know when enough bacteria has migrated?

OK, now I am focused.

I have read about ten years of archived posts on various subjects discussed on this forum, a few touched on your question. In particular, when a system is "upgraded" to a bigger display tank, or re-setup after a move, it can behave like a new aquarium. The new set up can have the usual sequence of nuisance growths and increased levels of nitrate and phosphate even when everything is transferred to the new container. Because the forum posts are usually problem posts, there is no way to tell how many upgrades went without any issues because those are rarely posted.

In the worse case scenario where your new tank will behave like a new tank AND you have stocked it instantaneously, you will want to procede with caution. Monitor the ammonia level often as you wean the new system from the old biofilter. I would guess it may take months for the new system to develop the biofiltration capacity of the old system. You may see the nitrate level rise before denitrification bacteria take hold. And phosphates are likely to appear for no apparent reason.

I hope others will chime in on their upgrade experiences.

[zeusfc]

Thanks Dan, that makes a lot more sense... Like you say, people normally only post when they have a problem!
FWIW, the rock work started a diatom bloom, but I added about twenty periwinkles and two RW8s in the same week, which completely cleared the problem. The new system is pretty much perfect at the moment, and I want to keep it that way, hence asking for others' experiences when doing this.

[bertoni]

Okay, maybe I'm not understanding, but I thought that the new systems was all setup and running, but the old sump was still plumbed into the new system. Is that correct? The new system and the old plenum are connected?

[zeusfc]

Yes!
New tank, (new "dry" rock, new 20lbs "live" sand
New sump, 10lbs new "miracle mud"

Connected to a remote old sump, with 50lbs Jaubert/plenum deep sand bed, and about 20lbs live rock which (I assume) is still the biological filter of the whole system.

[bertoni]

Okay, the new part of the system has gone through the normal setup stages of algal growth, etc, or at least as much as is going to happen. I don't know what the stocking level of fish is, so it's hard to say much.