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I want to change the substrate in my tank to either sand or a sand/gravel mix. But I only have one tank & don't have anywhere the fish can be while new substrate settles. Can fish handle substrate changes? I can only imagine how cloudy & awful it gets when pulling out all the old substrate, let alone putting in new stuff.

I had been looking at CaribSea Sunset Gold (0.1-0.4mm) -- but even in their directions, they say to let it settle for a week before adding fish.

http://www.fosterandsmithaquatics.com/p ... atid=21412

Is setting up a new tank the only time I can really switch substrates? I want to put in something finer to make the bottom-dwellers happier...

Any tips about how to make the switch plausible? Easier? Less stressful?

Any other suggestions for substrates? I saw a lot of suggestions for Play Sand or Pool Sand, but I also have a lot of plants that I want to be able to keep -- they wouldn't stay rooted or grow very well in sand, would they? Are these plant-friendly substrates also cory cat friendly?

Thanks for any advice!

Absolutely. Coincide this with a regular water change. I do it all the time when I want a change.

- Rinse new substrate really, really well.
- If you have plants or decorations in the tank, move them to one side.
- Leave filter(s) running. Using a cup (large plastic cups from McD's work very well ), start scooping out existing substrate slowly. This will minimize the amount disturbance. You will of course still up all sorts of goodies, but, if you do it slowly, it won't be as bad. Don't worry about this.
- Do one side, move items over to the side you just did and repeat.
- After the substrate is removed, let things settle for a bit. You want everything pretty much to sit on the bottom.
- Using just the tube of a gravel vac, remove all the gunk from the bottom. Using just the tube allows you to suck up all the gunk without removing a ton of water.
- Again using a cup, start adding the new substrate. Do this by filling the cup and then slowly lowering it into the tank. Fill the cup up slowly with water then lower to the bottom. Slowly dump and repeat. You will have very minimal disturbance doing this. Pour substrate away from filters. You will basically be piling it up on one side and then smoothing it out later.
- Fill with fresh water and scape accordingly.

Whilst reading up on tanks, i came across some text that cloudy water caused by unsettled substrate is harmless to fish. The only downside is that its not pleasant to our eyes. A good filter will help clear the water fast. You might want to add fine wool as a filter medium, i read it traps sand well.

Changing substrate is pretty easy, but I would recommend against leaving the fishes in while you do it. Depending on the size of your collection you'll need to pick up a second tank to place the animals in. Truth be told you need a small second tank anyway for quarantine/hospital etc reasons. The second tank can be quite small as the fishes will only be in it about 24-48 hours.

1) Fill 2nd tank 75% with water from old tank. Top off with fresh water.
2) Move all filtration over to holding tank.
3) Move all fishes to holding tank (note the "holding tank" can even be a plastic container. Anything that holds water).

Now tackle the main tank:
1) Buy a one meter section of 1" hose if you do not already have one
2) Remove all plants, wood, large stones etc from main tank
3) Siphon out old substrate into a bucket. Depending on the size of the tank this may take several.
4) After a good washing (I used my wife's colander so many times for this she gave it to me and bought a new one) place new substrate in main tank
5) Let it settle a couple of hours then go back and replace decor (plants, wood etc) as desired.
6) Now, Let the set up settle for 24 hours

Repopulation
1) Move filtration back to main tank
2) Add 90% of water from holding tank back to main tank. Top off as necessary with fresh water
3) Add the fishes

I am being generous with advising 24 hours to let the tank settle. I have pulled off substrate changes using the above technique in a matter of hours. The key is siphoning out the old substrate so that you are eventually left with a tank about half full that still has nice, clear water.

-Shane

James & TBone -- thank you for the tips about changing the substrate with fish present : )

Shane,

If I remove the fish -- will they really be all right crammed together in a 10 or 20 gallon tank? Will catching them all & keeping them there stress them out to the point of illness? I have 2 smaller filters running on the current tank. Should I put them both on the QT tank or would it make sense to leave one on the real tank to help clear up that tank faster?

I'm trying to change from gravel to sand & was thinking of mixing 2 types of substrate to get a slightly less uniform look. I was also hoping that the larger stuff would help keep plants rooted properly. The two types are (0.2-1.2mm) & (1-2mm). Does it matter if they are mixed uniformly, or should the larger type be on the bottom to help prevent gas pockets from forming? That probably wouldn't last after a vacuuming though. How deep a layer should I put down? I know the disadvantage of too much - evil gas pockets. Is there a problem with a layer that is too thin? Would it just get dirtier quicker?

Thanks for all the advice - very much appreciated!
Amanda

just a couple of thoughts.....sand is a far better substrate for bottom dwelling fish, but not ideal for plants (as substrates shouldn't be too deep). Have you thought about having plants that root to wood or rocks - like anubias, java moss, java fern, bolbitis, monosolenium?

There are actually plenty of plant keepers who do plants in sand. You just have to make sure it's sand that doesn't pack down tight. Most aquatic plants uptake nutrients from the water column as well as the root systems, and if you dose the water column (as you would for epiphytes like java ferns, anubias, and the like), the roots act as nothing more than anchors anyway.

It IS definitely easier to grow plants in specialized substrates (don't have to dose the water column as much, as the substrate uptakes the excess and stores it allowing for eventual release), but it's certainly to grow rooted plants in bare bottom tanks even, as long as you have all the necessary nutrients in the water column (carbon, N, P, K, trace), and sufficient light, of course.

I have hundreds of Vallisneria and Sagittaria growning in sand - without any special care for them. I aklso have Hygrophyla and Elodella this way - lost and lots of them

What comes out of the fish, is what the plant will need - even the relative amounts are correct

However, some plants - Echionodorus, for instance, like to have clay in their substrate. OK, so I pprovide them with a clay substrate - in a pot. Bottom: a lot of clay, going upwarts more and more sant, top layer pure sand

Nice advantage of this method - I can replace them without any problem for the plants. I got a lot of Echionodorus from Uruguay, which go into my garden, just as the fishes do. I think they like the extra light

If I remove the fish -- will they really be all right crammed together in a 10 or 20 gallon tank? Will catching them all & keeping them there stress them out to the point of illness? I have 2 smaller filters running on the current tank. Should I put them both on the QT tank or would it make sense to leave one on the real tank to help clear up that tank faster?

I can't really answer that as I do not know what fishes you have or how big they are. You will need to adjust the size of the holding tank as necessary. Catching and moving the fishes will not stress them out.
I would move both filters to the holding "tank" (remember that this can be a simple plastic tub or plastic storage container. I would not use a filter to help clear the main tank. If you carefully siphon out the old substrate with a 1" hose, there will be almost nothing to clear up.

I'm trying to change from gravel to sand & was thinking of mixing 2 types of substrate to get a slightly less uniform look. I was also hoping that the larger stuff would help keep plants rooted properly. The two types are (0.2-1.2mm) & (1-2mm). Does it matter if they are mixed uniformly, or should the larger type be on the bottom to help prevent gas pockets from forming? That probably wouldn't last after a vacuuming though. How deep a layer should I put down? I know the disadvantage of too much - evil gas pockets. Is there a problem with a layer that is too thin? Would it just get dirtier quicker?

I am a big fan of mixing various sizes of sand/gravel for a more natural look. You are correct that it is impossible, over time, to keep the layers from mixing. Try a ratio of 70% sand, 20% small gravel and 10% medium gravel. Just mix it all up and slope it from 2" in the front to 3" deep in the back. Using this substrate combination with plants I have never experienced gas bubbles.
Below is a tank I am running now with a very similar substrate to what I described above. Note that the substrate below is, however, not an artificial mix. It is actual substrate I collected from Lake Victoria at Entebbe.
-Shane

hey guys, im not sure if this question is answered but doesnt substrate have beneficial bacteria too?
so wouldnt a substrate change start a mini cycle?

In a more or less normal situation, we have a tank, with plants and/or wood & stones, with substrate and a filter.

Roughly speaking, the bacteria are everywhere - on all decorations, on the substrate and in the filter

Assuming only the substrate is remouved, and the rest of the decoration remains (palnsts are rerooted, obviously) while the filter continues its work, only a fraction - 40 % or less - of the bacteria wil lbe remouved

However, I think it is rather hard not to disturb the other factors while changing the substrate - especially a filter has a good change of becomming clogged, and than rinsing the filter will remouve another 40 % or so.

This would mean too much has been remouved, but on the other hand, loss of 80 % will, most likely, be restored in a few days.

Cycling a new tank takes so long, because the first few phases of doubling the population of nitrificating bacteria does not amount to much: 1 2 4 8 16 32 64 128 256 512 1024 2048 4096 and so on, to a few billion: this kind of exponential growth has the disadvantage of starting very, very slowly

DJ-don wrote:hey guys, im not sure if this question is answered but doesnt substrate have beneficial bacteria too?
so wouldnt a substrate change start a mini cycle?

Yes, it will have some beneficial bacteria. But if the main filtration of the tank is an external or internal filter, then MOST of the beneficial bacteria will be in the filter, not the substrate.

--
Mats

To the original poster. If you do not want to buy another tank to hold your fish while changing the substrate, you can purchase a couple of large Rubbermaid containers from someplace like Walmart. You can usually pick up a large one capable of holding up to 50-60 gals for just a few dollars.

They are also usually large enough to hold all your filter and other equipment as well.

I used 3 of these said containers when I moved from northern Virginia to eastern North Carolina several years ago. When all said and done fish and filters were on there for roughly 12 hours. No issues or fish losses.

Just make sure you give the containers a good clean/rinse as you would anything you were buying to put into your tank.