Swapping substrate

[Scooter_916]

So I've had my tank set up now for about 5 months, I'm wanting to swap over from natural colored gravel (pea size) to black sand. I've currently got just a few volcanic rocks with some have fern attached, and a couple pieces of drift wood, I'd like to loose as little beneficial bacteria as possible that in and in the gravel, whats the best way to do that? Add in sand slowly and eventually sift out the gravel? Or just do a full swap on my next big water change? I also have a dual sponge filter with bio balls in the bottom. And a small HOB filter with bio balls and a cube of sponge. I'd like to get more plants and plant it more heavily. Thanks in advance

 

[Uberhoust]

It would depend on the size of the tank and the current amount of waste in the substrate. If you have a big tank 55+ with little accumulated waste I have replaced 1/2 the substrate one day and about 3 days later replace the second half. But if you have accumulated waste in the gravel disturbing the gravel can lead to a ammonia spike which would not be good. For me if I was in a moderate to high waste situation or if the tank was smaller I would temporarily place the fish in some other holding container with air and heat, because its going to take sometime to get the gravel out. During this time if you can keep the filter going in the temp tank then you keep the bacteria alive, which is good, the filter materials cannot dry out. Then remove the remaining water and gravel from the tank, and replace it with the sand. Fill and treat the tank for chlorine then add back the filter and heater. During such a substrate change it is a good idea not to clean the decorations and wood until the bacteria also colonizes the surface of the sand.

The whole objective is to get the new clean sand into the tank while disturbing the establish bacterial colonies as little as possible. As well keeping the fish as little stressed as possible, to this aim I have placed blankets over the containers containing the fish. Others might have different ideas.

 

[enricosonic]

I was about to post something similar but nowhere near as thorough. Knowing the the size of your (OP) tank is key to providing a definitive answer.

 

[Scooter_916]

I have a 10 gallon

 

[Scooter_916]

I have a small tank I can put them in temporarily while swapping the substrate. should I just siphon the water out of the main tank into the holding tank, then fresh in with the sand?

 

[Byron]

Use a "temporary tank" to house the fish and the existing plants and decor, and run the filter on this tank (heater too obviously). This is significantly less stressful that doing a substrate replacement with fish still in the tank. For one thing, you may encounter anaerobic spots and other members have killed fish like this. Drain water from the top of the existing tank to fill the temp tank, move over the filter, decor and plants (they can be left floating, no need to plant), then net the fish over. Then you have all the time needed to do the swap.

When done, move the hardscape decor back, and the plants (you might want a few inches of water, plants in air can be delicate and break). If the water is cloudy (usually will be), drain it to the sand and refill carefully with dechlorinator. Move the filter back, and if all is good, net the fish. Use fresh dechlorinated water in the new setup; provided parameters (GH, pH and temp) are basically the same this is not a problem.