Soil

[wtusa17]

I want to put soil in the bottom of my tank for plants and I already have fish. I know I have to take them out and empty the tank but any recommendations on how to keep the fish healthy while I’m redoing the tank and successfully do the soil in the tank?

 

[Retired Viking]

You can always use plants that don't need soil but absorb what they need from the water. Java fern, hornwort, moneywort, java moss and more. Many only have roots that anchor them in place so you can "plant" them in sand or gravel. So you would not need to move your fish. The plants I have do not need soil added to the tank. Gravel or sand work just fine.

 

[wtusa17]

I was looking to add the soil bc it is cheap and the plants I have now are not doing well but they were not healthy in the first place. I am looking to maybe do a carpet of some sort

 

[Colin_T]

What plants do you have?
What sort of light do you have (LED, fluorescent, etc, and how many watts)?
How long is the light on for?
Do you use aquarium plant fertiliser?

 

[wtusa17]

The plants I have are a bust and are basically dead. I have a LED light. The light is usually on for about 12 hours I would say. I have seachem flourish that I use.

 

[Colin_T]

Most pet shops sell aquarium plants that consist of marsh plants and true aquatic plants. The marsh plants die when put under water, whereas the true aquatics will normally do well.

Try increasing the photo period to 16 hours a day.
If you get lots of green algae then reduce the light by an hour a day and monitor the algae over the next 2 weeks.
If you don't get any green algae on the glass then you need more intense light.
If you get a small amount of algae then the lighting time is about right.

Some plants will close their leaves up when they have had sufficient light. Ambulia, Hygrophilas and a few others close their top set of leaves first, then the next set and so on down the stem. When you see this happening, wait an hour after the leaves have closed up against the stem and then turn lights off.

Some good plants to try include Ambulia, Hygrophila polysperma, H. ruba/ rubra, Elodia (during summer, but don't buy it in winter because it falls apart), Hydrilla, common Amazon sword plant, narrow Vallis, Water Sprite (Ceratopteris thalictroides/ cornuta).
The Water Sprite normally floats on the surface but can also be planted in the substrate. The other plants should be planted in the gravel.

 

[seangee]

Use play sand. Its cheap and won't affect your water chemistry. You can add root tabs for nutrients.

I changed the substrate in this tank without removing the fish. It only took a couple of hours. Start taking the old substrate out a few days before and make sure the new sand is thoroughly rinsed before you put it in. I cut the base off a 2l milk bottle and filled it with sand. Then I put it into the tank upside down and removed the lid to allow the sand out without making a mess. You could also use a soda bottle.

 

[wtusa17]

Thanks but I don’t want to mess up my cycle so I’ll just use my regular fine gravel as a cap for the soil

 

[Byron]

I responded to your subsequent thread about soil before seeing this older one, so I will copy over my advice so it is here.

Personally I would not do this due to the significant risks (to fish) plus the fact that it really has minimal benefit for plants. I have had planted tanks for 25-30 years, and researched the various methods and even tried a few. Soil is one I have never even considered after researching it.

Soil contains organics, and this is the benefit. Organics decompose producing CO2 (the initial high level of CO2 is the only benefit for plants, I'll come back to this) and ammonia. The level of ammonia can be sufficient to kill the fish in the tank. Most soil substrate authorities advise six months before fish are added, and using a dry start to begin with; I won't get into the complications of this, but you can research it.

Obviously the ammonia is the main risk. As for CO2, it is true that more will initially be produced from soil than from an inert substrate like sand or fine gravel, but within a few months the latter will be just as beneficial. Organics naturally build up in the substrate whatever it is composed of, and this is the main source of natural CO2. Diana Walstad, who is the prime advocate of this method (soil) admits in her articles and book that any inert substrate like sand will be equal to soil (with respect to nutrient benefit) by the end of the first year, and the soil would then (or should then) be replaced, starting all over again. This is not required with non-soil substrates. The initial CO2 is the only "benefit," as any mineral nutrient in the soil will be minimal and used within a few months if not sooner.

If you are intending an "aquatic garden" planted tank wiithout fish, then soil has no real detriment. But if you intend a fish tank that happens to have livee plants, it is the most risky method.