# Replace substrate in established tank?



## sohankpatel

How can I replace my regular gravel with Seachem flourite? I CANNOT dismantle the entire tank because have nowhere to keep my fish as I rebuild the tank. I was thinking that I could put the fish in a bucket and remove a quarter of the water. How can I remove the old substrate and put the new one in without making the water filthy?


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## WaterLife

I am guessing the current gravel is inert and so you want to take it out.

Safest way to do this is firstly try to save at least 50% tank water by siphoning it into buckets. Then put fish and plants into a bucket with some tank water (not too little water that the fish quickly pollute it). Then you are free to disturb the current substrate which probably has a lot of toxic nitrogen gas pockets under it. You can either take out the substrate right away if you dont care to clean it. Or you can stir it up in the tank to release the dirtyness and fill it with tap water, siphon the dirty water back out, fill it up again, empty water again, fill it again (repeat until water is clear/not murky), then remove old substrate. Or you could remove substrae and clean out of tank later. Add new substrate (not sure if non-inert substrate is still recommened to be rinsed first). Maybe do another quick water change if water gets murky from new substrate. Once clear/clean enough water, only fill about half way so you can fill the other half with the saved aged tank water. Then replant and then add fish. Walla.

You could do the switch while the fish are in their but that is much messier, takes longer and is much more riskier in exposing the fish to nitrogen gas releases.


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## sohankpatel

The tank will only be a few months old, so do I still have to worry about nitrogen has?

Bump: The tank is also 55 gallons so...


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## AndreyT

Firstly, where did "nitrogen" come from? Nitrogen gas is completely safe. There's no such thing as "toxic nitrogen gas". The popular scare about toxic gas pockets in aquarium substrate actually refers to _hydrogen sulfide_.

Secondly, the "deadly" effects of sudden release of hydrogen sulfide collected in the substrate in freshwater tanks are greatly exaggerated. The evidence of anything ever being killed by such release is anecdotal at best. Common sense says that it is simply impossible.


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## sohankpatel

Any other methods that are efficient?


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## keymastr

The biggest problem is keeping the bio-media alive while you do the swap. I would plan on putting the filter/filters on a bucket of tank water so that they continue to be oxygenated. If this is the same bucket the fish will be in even better so long as the circulation is not too strong for them. Depending on how many fish you have you may find a large Rubbermaid tub to be better and provide plenty of room for fish and filters.

You do not want the filters shut down for an hour or so since you will be removing a bunch of bacteria that is on the existing substrate. That means the bacteria in the filters will have to work even harder. I would also not scrub the tank and decorations or clean the filter if you can help it. Wait to do that until the new substrate has been established for a few weeks. Everything in the tank has bacteria that is currently removing ammonia so you want to keep it doing that until the new substrate is helping to do that also.

Once the fish and water is removed just scoop out the old and put in the new that you have rinsed thoroughly outside in a bucket with a hose. Rinse and stir until the water runs clean no matter how you disturb it. Even then it will probably be cloudy for a few days.


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## TINNGG

Faith, trust, pixie dust?

I've only ever removed substrate once on a large tank. Was a colossal pain in the patootie. And this was an unoccupied, dryish tank. I was moving it from one room to another and decided I wanted a finer substrate and no UGF. I still have the finer substrate - mixed with flourite to be sure - some 20 years later. If the tank ever springs a leak requiring me to empty it, then I'll replace it. Otherwise... Hahahah! No.

Just an opinion - changing substrates in small tanks is as easy as changing a shirt. Once it requires more than one person just to move the empty tank, it gets complicated, if only because most people don't habitually leave large tanks empty so you're almost guaranteed livestock relocation.


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## FatherLandDescendant

keymastr said:


> You do not want the filters shut down for an hour or so since you will be removing a bunch of bacteria that is on the existing substrate. That means the bacteria in the filters will have to work even harder. I would also not scrub the tank and decorations or clean the filter if you can help it. Wait to do that until the new substrate has been established for a few weeks.


I completely redid one of my tanks and left the canister filter off overnight for around 14-15hrs without any problems. If it's a HOB don't let the pads dry out.

I do agree that you don't want to clean the filter at the same time, and would be best to not clean any hardscape (drift wood and/or other decor) just make sure you also keep such in a bucket of tank water.

You could also keep a sock full of the old substrate and hang it in the tank for a week or so in the filter flow would help.

Otherwise I suggest getting a bottle of safe start from wallymart or the LFS. Your going to have a mini cycle but as long as you leave the filter intact it should be brief.

Bump:


TINNGG said:


> Just an opinion - changing substrates in small tanks is as easy as changing a shirt.


Took me a tad better than 1/2 a day to reconfigure a 40b:confused1:


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## tetra73

Go to Lowes or Home Depot and to get one of those 18g to 30g tote storage box. About $8 the most. Use it to keep the fish until your tank is ready. Makes sure you put some supports or ledges around the storage box because they will wrap and bow outward by the water volume. Put your filter in there.


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## TINNGG

FatherLandDescendant said:


> Bump:
> 
> Took me a tad better than 1/2 a day to reconfigure a 40b:confused1:


Hahah! I have one of those things sitting on my kitchen counter. Not exactly a small tank. I remember looking at my daughter as we were negotiating enough space for it and saying, "it looks bigger here than it did in the store." She looked at me like I was nuts and told me that it looked just as big in pest mart as it did in the kitchen.

It's a grow-out tank though so no substrate. If I ever locate untreated 4x4s, it's going to be moved to a less...overwhelming location.


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## sohankpatel

I dont want to remove all the water, that is why I am asking this question, how can I replace I be and replace substrate with water in the tank, cause it is a massive pain in the @$$ to re fill that tank


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## tetra73

sohankpatel said:


> I dont want to remove all the water, that is why I am asking this question, how can I replace I be and replace substrate with water in the tank, cause it is a massive pain in the @$$ to re fill that tank


You have to remove and to refill your tank water after the substrate swap, period. With my method I mentioned, you can leave the fish in the storage box for few days while waiting for the tank water to cycle. Remember to put a lid on it. You can reuse the water from the storage box. That was I did when I switched to dirt from my existing high tech tank. The swap (substrate to dirt) took one day but I needed about 2 to 3 days to ensure that any possible ammonia from the dirt is totally gone from the water column. 

Is good you have 2 filters here while using your primary filter on the tank and the other one on the temp storage box...using your old filter medium.


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## schnebbles

I just did this. I may need to add some quickstart stuff. It took me about 6 hours I think for a 40b.

I put 1/2 the water in a trash can, pulled plants and put most in there, put fish in a 5gl (I didn't think about too many in there for too long) and some plants in their bucket. Took out old sub, rinsed the new and put it in, filled up with the water I removed using a pump, put plants and fish back in and finished adding new water. It wasn't all that bad.

I didn't think about the filters or anything, i ended up with a couple sick fish and one died a day after. I either super stressed them in the bucket or had too many. I'm keeping an eye on the tank parameters but I think I should add some quickstart bacteria.


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## FatherLandDescendant

sohankpatel said:


> it is a massive pain in the @$$ to re fill that tank


One of the best investments you could ever make, hook it to the sink and fill away:hihi:

http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+3728+23593&pcatid=23593&r=633


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## sohankpatel

Any suggestions for a pump that I can use to pump the water out of the tank, and then use it to pump that water from a trash bin back in?

Bump: Or can I just put the canister filter input in the bin, and the output in the tank?


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## Dropline

sohankpatel said:


> Bump: Or can I just put the canister filter input in the bin, and the output in the tank?


I REALLY like this idea, I do not see why it would not work and actually would seem better being there would be junk in the bottom of the bin from the fish waste. 

I think I am going to get a longer hose for my small canister and do this when I convert my substrate to dirt later on. 
:icon_idea Thanks for the GREAT Idea!!! :icon_idea


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## AndreyT

sohankpatel said:


> Bump: Or can I just put the canister filter input in the bin, and the output in the tank?


Only of you place the tank and the bin at approximately the same horizontal level. If the bin is below the tank, then in general case this will not work. Canister filters are not designed to _lift_ water - the pump is too weak. Canister filters are designed to siphon water from some water level and reverse-siphon it to _the same_ water level.


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## nodim

I've swapped substrate with a running Tanganyikan tank in the past. 75 gallon tank. Basic process was to remove all rocks etc. from tank, then unplug filters and heaters. Removed about 1/2 the water, then with a plastic children's beach shovel, removed the old substrate. Once that was gone, slowly pour the new substrate into the tank. Unless you are beyond meticulous with rinsing the new substrate, the tank is going to be dirty. Just digging up the existing creates enough mess.

I did the change with the fish in the tank, but both substrates were inert, and had no danger of changing water parameters. 

FWIW - I don't recommend this approach, it is much easier to remove all the water and fish first. As for your canister, the BB will be fine for the couple of hours it will take to swap the substrate and refill the tank. As someone else pointed out, don't change/clean the filter for a while before or after changing substrate as you want to ensure the BB are in good shape. If the fish are out, fill the tank back up - think of it as a large water change add your conditioner, connect and turn on the filter, run it until you are happy with the clarity - then add the fish. All that is really needed is a couple of buckets, something to put the old substrate into, and towels.


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## schnebbles

I used a cheap $10 pump from Harbor Freight - I think they are pond pumps. It's quite handy!


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## CrypticLifeStyle

What kind of fish? I think your being way too cautious. I've done swaps so many times, and have never lost anything due to the process of the swap.

I move twice a year, and i have cichlid tanks, planted tanks, shrimp tanks, reef tanks. 
I have to do this all the time. 

Get as many buckets as you would need to hold 25% of the volume or minimum a 5g bucket or a tote. Run the filter in the bucket or tote with the tank water. 
Put the fish in the bucket(s)/tote.

Drain out the rest into the sink/tub whatever. scoop out the substrate, rinse out the tank, add the new substrate, fill up the tank with 75% new water, add seachem prime.
View it as a 75% water change...

Wait a few hours, add the equipment back, pour the fish in, turn everything on.

There's more steps i take with my reef tanks as it's way more time sensitive, but it's never failed me yet for a couple decades.

P.S. be sure to turn off the heater 15 minutes in advance, and when the heater goes back in the tank make sure to let it sit for at least 20 minutes before you turn it on.


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