Redoing a gross tank

[LukeHawk]

Hi there, I was wondering if anybody could help me out a bit..

I've had many freshwater tanks in my time, but I will be taking care of my first saltwater tank very soon. It's not being started from scratch, as I'm buying the 4ft tank and stand from somebody who already has it up and running (sump, skimmer, everything except lighting).

My problem is that I really don't like the way it's all laid out right now.. I would like to redo the substrate, use the opportunity to clean everything up (there's quite a bit of algae growth) and rearrange a few things.

So my question is, what do I need to look out for? Can I swap out substrate without messing up the nitrifying bacteria? It's currently gravel and I'd like to put in sand.
Once I move the tank to my house, I'll have most of the old water still, but seeing as the tank will be mostly empty, it's a good time to do my changes.

 

[CAPSLOCK]

Is there anything alive in the tank now? If no, it will be easier to just tear it all down and take your time setting back up with whatever changes you are doing. Or if it is covered in particularly invasive pest (ie, bryopsis, aiptasia) that you want to eradicate by bleaching the rock. If the rock has just normal unsightly algae, you can ignore it during the initial breakdown but just scrub it good before putting it back in the moved tank.

Assuming you are keeping whatever rock and/or there are live critters included, you'll have to drain, move, and set back up more quickly. I recommend having a holding tank for whatever critters/rock you are transferring over. It can be a bucket, tote, 20g tank, whatever. Drain some clean water into the holding tank first, and then start to move over the rock / critters. If fish, once you have removed the rock they will be easy to catch. Or keep an eye on where they hide in the rock and make sure any rock with a fish hiding in it gets plunked right in a holding tank. Add a heater and water movement to the holding tank, so you can take your time setting the tank back up.

Since you are moving between houses, basically you'll be moving everything to your house to a holding tank there - so at the tank's house you will be bagging fish/snails/corals and putting live rock in buckets, then moving them to the holding tank as soon as you get home.

You will want to use mostly new water. Have some made at home, mixed and warm and waiting. Don't save any of the water once you start to mess with the gravel, as all sorts of gunk will be released. Once all the living things and rocks are out, drain the tank and chuck the gravel.

Does it have live rock? Or some form of biological filtration (bioballs or such)? If so, go ahead and remove all the gravel and replace with sand. If not, you'll need to save a few handfuls of gravel in a pantyhose or something to help preserve the beneficial bacteria. You could take it back out after a few weeks. Or, add some cycled live rock to get the tank cycled that way.

Keep in mind when you set back up, to make sure any rock work is on the bottom glass, not on sand - that will prevent falls if critters burrow.

 

[LukeHawk]

Is there anything alive in the tank now? If no, it will be easier to just tear it all down and take your time setting back up with whatever changes you are doing. Or if it is covered in particularly invasive pest (ie, bryopsis, aiptasia) that you want to eradicate by bleaching the rock. If the rock has just normal unsightly algae, you can ignore it during the initial breakdown but just scrub it good before putting it back in the moved tank.

Assuming you are keeping whatever rock and/or there are live critters included, you'll have to drain, move, and set back up more quickly. I recommend having a holding tank for whatever critters/rock you are transferring over. It can be a bucket, tote, 20g tank, whatever. Drain some clean water into the holding tank first, and then start to move over the rock / critters. If fish, once you have removed the rock they will be easy to catch. Or keep an eye on where they hide in the rock and make sure any rock with a fish hiding in it gets plunked right in a holding tank. Add a heater and water movement to the holding tank, so you can take your time setting the tank back up.

Since you are moving between houses, basically you'll be moving everything to your house to a holding tank there - so at the tank's house you will be bagging fish/snails/corals and putting live rock in buckets, then moving them to the holding tank as soon as you get home.

You will want to use mostly new water. Have some made at home, mixed and warm and waiting. Don't save any of the water once you start to mess with the gravel, as all sorts of gunk will be released. Once all the living things and rocks are out, drain the tank and chuck the gravel.

Does it have live rock? Or some form of biological filtration (bioballs or such)? If so, go ahead and remove all the gravel and replace with sand. If not, you'll need to save a few handfuls of gravel in a pantyhose or something to help preserve the beneficial bacteria. You could take it back out after a few weeks. Or, add some cycled live rock to get the tank cycled that way.

Keep in mind when you set back up, to make sure any rock work is on the bottom glass, not on sand - that will prevent falls if critters burrow.

First of all, thank you so much for the great in-depth reply. I really appreciate the time and effort.

Yes, there are a few fish and a shrimp, as well as a few soft corals.
Also all the rock in the tank is live rock.
I dont actually have a holding tank, so I will go to my LFS straight away to get one, and prepare some salt water for the fish.

So as you say, because the tank is filled with live rock, I'll just scoop out all the old gravel and replace.
I will try and preserve as much of the existing tank water as I can (it will be drained into buckets for the move) and then re-add that as well as topping up with my own mixture to make the difference.

Again, thanks for the help. I will keep this thread up to date with my progress.

 

[CAPSLOCK]

You don't have to use an actual tank for it - a rubbermaid tote will work just fine (no HOB filters on totes, they have a tendency to fall off... also make sure the heater isn't against a plastic wall of the tote). I've also used Home Depot buckets. A brute trash can works well for this also. Basically any water holding container, plus heater and water movement. If one of your new fish is a tang, make sure to have plenty of oxygenation in the water (water movement at the water surface, or an airstone).

Just make sure whatever water you save is pulled off first, not after you start fiddling with the gravel. If you've never done it before, it is quite impressive (gross) how much nasty ungodly gunk comes up from several-year-old-not-impeccably-maintained-substrate. This also means pulling whatever water you may keep before moving any rocks that are submerged into the gravel.

Are you using RO / RODI water? If the tank is gross, and you're going to be using nice new water, you might consider not saving any old scuzzy water to go into the new tank. Obviously you'll need to use some of the water for transporting and for holding the LR / critters until the tank is set back up.

Take the opportunity to really look at the rock for any pests that you would prefer not to bring along.

Any equipment that is "crusty" can have a vinegar bath to remove calcium deposits or other scuz.

I just upgraded my SW tank, and at the same time got an RO filter to improve water quality. I drained all my holding tank water first, then moved fish / rocks / coral (and moved my refugium contents into a separate little 5g holding tank). Then broke down everything else, saved some sand for the microfauna but rinsed (and rinsed, and rinsed) the rest. The RO filter means that water is made more slowly, so it took a good 24hrs to make all my new water (and then make it into SW). My rocks / coral / fish were in a 20L holding tank for 2 days, fuge contents in theirs for about 5 days while I set everything back up. I had some plumbing difficulties setting the sump back up and it delayed that portion. I did not add any of my old water in - just matched temp and salinity. Only had a few corals that didn't make the transition - ricordea mushrooms that weren't doing so hot before hand either - everything else transferred fine, and still no losses.

Also, how is your stand setup w/ the sump? If it isn't a stand that is very well finished (water resistant finish inside the stand), consider adding a sheet of plastic shelf lining under the sump - it'll protect the bottom of the stand for the inevitable drippage that happens. It's this type: http://www.amazon.com/dp/B0027P9516/?tag=myfnet0c-20 - you can cut it easily to fit (and it comes in wider widths as well).