Tank Soil Substrate

[mhancock]

Hi,

Has anyone successfully used soil substrate with a bit of gravel on top (Walstad method)? If you did:

• What kind of stocking level could you get up to?
• Did you have any cycling issues?
• Did you get rid of the filter altogether?
• If in the UK - what type of soil did you use?

I'm thinking of replacing all of the substrate in my 225l tank with soil and black gravel, so would appreciate your thoughts before I do it!

Thanks,



Mark

 

[Mikaila31]

I've done both soil and sand, but I don't follow the walstead method exactly. I always change 50% water every 1-2 weeks.

What kind of stocking level could you get up to?
Stocking levels can be anything from light to heavy depending on the type of fish, if you keep the filter or not, and the growth rate of the plants.

Did you have any cycling issues?


No. Least in terms of the nitrogen cycle. Usually its best to do a couple large water changes first week too remove any leached nutrients. Mainly to avoid algae issues while plants establish.

Did you get rid of the filter altogether?

Yes or close too If in the UK - what type of soil did you use? it. I had a 15 gallon with two dozen fish plus shrimp and snails that was unfiltered with only a powerhead. It did wonderfully till I moved it 15 miles since then its been very upset and is a shrimp only tank now. I move again in a few months were it is getting torn up and redone with new soil.

My 20 gallon has a filter that runs most days and the tank sits stagnant at night. Sometimes the filter is off for a couple days depending on stocking. It currently has a light stock of 20 or so small fish but has temporary house up to 50 for a month. It never had a problem either way. I didn't set this one up till after I moved.

If in the UK - what type of soil did you use?

I'm not in the UK. I used regular old top soil that I dug up from a wooded area along with some clay/mineral rich dirt I also dug up. I've used both sand and gravel to cap the soils. Sand keeps dirt down better then gravel when planting/pruning. It is harder to dig into a soil cap as it seems to compact over time.

 

[tomtomtom1230]

Did you have any cycling issues?

No. Least in terms of the nitrogen cycle. Usually its best to do a couple large water changes first week too remove any leached nutrients. Mainly to avoid algae issues while plants establish.

I thought excess nutrients in the water are not a cause for algae? I was under the impression that lighting, CO2 and flow (or the lack of all three) in the tank are a far more direct cause.

 

[tomtomtom1230]

Sometimes the filter is off for a couple days depending on stocking. It currently has a light stock of 20 or so small fish but has temporary house up to 50 for a month. It never had a problem either way. I didn't set this one up till after I moved.

If going filterless is the point of this method, why bother with the filter at all? Leaving it off for days at a time cannot allow any beneficial bacteria to flourish and a strong siphon will allow you clear any debris, a filter is unneeded as far as I can see but I've never tried this method before.

EDIT: Sorry, I'm being curious, not being a critic trying to get a grip on how this works.

 

[mhancock]

Sometimes the filter is off for a couple days depending on stocking. It currently has a light stock of 20 or so small fish but has temporary house up to 50 for a month. It never had a problem either way. I didn't set this one up till after I moved.

If going filterless is the point of this method, why bother with the filter at all? Leaving it off for days at a time cannot allow any beneficial bacteria to flourish and a strong siphon will allow you clear any debris, a filter is unneeded as far as I can see but I've never tried this method before.

EDIT: Sorry, I'm being curious, not being a critic trying to get a grip on how this works.

Likewise, I don't think I'd be confident about getting rid of the filter altogether, and of course if I did turn it off and realised in a few days that there was an ammonia spike, then the bacteria in the filter would all be dead by that point and I'd have a huge issue of a fully stocked tank not being cycled.

 

[Mikaila31]

Sometimes the filter is off for a couple days depending on stocking. It currently has a light stock of 20 or so small fish but has temporary house up to 50 for a month. It never had a problem either way. I didn't set this one up till after I moved.

If going filterless is the point of this method, why bother with the filter at all? Leaving it off for days at a time cannot allow any beneficial bacteria to flourish and a strong siphon will allow you clear any debris, a filter is unneeded as far as I can see but I've never tried this method before.

EDIT: Sorry, I'm being curious, not being a critic trying to get a grip on how this works.

The point isn't really to go filterless. A lot of walstead tanks do still have filters. Even something as simple as a powerhead with a sponge over the intake is still a filter. That tank has a internal filter that has been with the tank long before it was a soil tank. I've no desire or need to swap it out for a powerhead. Its in my bedroom and kinda noisy at night so I turn it off when I sleep. A tank can operate filterless just fine, but what you do usually need is water movement. Some form of circulation to evenly heat the tank, move nutrients around and bring oxygen down to the lower levels. Soil substrates are often anaerobic, mine let up lots of bubbles if you push on them. Depend in the bioload the tank can sit completely stagnant for 3 days up to a week. Then my fish usually start showing signs of low oxygen.

Also there is always debris in a soil tank, especially one that is truly unfiltered. That pretty much goes for any planted tank. You can siphon all you want and a filterless tank is never going to be as clear as a filtered tank. You can get it close though and from a distance it is hard to tell. My filterless tank always looks dirty after I syphon it then it did before, then it takes it a few days to get the clarity back. If you do filterless with just a powerhead and no prefilter make sure you still take apart and clean that powerhead regularly. I do siphon my tanks, the 15 gallon sand one doesn't look all that bad most of the time. Yet despite that the powerhead I have in there fills up with basically mud/mulm to a unbelievable extent. There is nothing wrong with using a filter, even with a simple sponge you can't really separate mechanical and biological. Either way the plants and filter bacteria are consuming the same food source. One way or the other it works out. I know most won't care, but filtering the particles from the water will effect the biology of the tank in terms of all the little inverts and copepods that like to live in there. Bamboo shrimp also seem to flourish in unfiltered tanks.

Light, CO2 + other nutrients are the cause of algae. You can have many excess nutrients in the water and not have algae, if you have lots of happy establish and growing plants. Yet things must be balanced, too much light, too little light, too many nutrients, too little nutrients can all cause algae if things are out of balance. A single lacking nutrient of the 17 or so plants need can limit their growth rate leaving nutrients available for algae to take hold. Other things like low circulation can also favor the growth of some types of algae. Nothing specifically causes algae, if it did then algae would be easy to manage and eradicate. Usually it is due to a number of factors all connected.

 

[tomtomtom1230]

I'm on the same page now, thanks for that!

 

[mhancock]

Thank you Mikaila31 , very helpful