Planted/Walstad Method Tanks

Since I started posting on this forum, I've several times mentioned my preference for densely planted tanks and also my interest in the Diana Walstad style of low tech “natural” tanks. Having made some progress over the last few months, I thought people might be interested to see some photos and hear about my experiences so far. The Walstad method is basically (in her own words) “moderate lighting, a substrate enriched with ordinary soil, and well-adapted plants.” It also means less water changes and gravel cleaning. This is in complete contrast to the “high tech” proponents who insist that to grow plants one must have enhanced lighting (expensive), special gravel additives (absurdly expensive) and Carbon dioxide generation (either very expensive or messy).

I've found it difficult to get decent photos of my tanks, in spite of following all the recommendations for aquarium photography. However, I hope the two following at least demonstrate that it is perfectly  possible to get good growth of plants without any of the three quoted requirements.

Both of the photos here show 80 cm tanks of about 110 -1 20 litres, planted up at the beginning of December.

The first shows about 70% of one tank, to illustrate how densely plants can grow. These have already been drastically pruned twice, and need doing again. You can only see one fish (Lake Kutubu Rainbow) but there are actually 14 in the tank. It's rare to see more than half of them at once as they all move in and out of the plants, apart from the rainbow who stays permanently under the place where the food comes in …............... greedy devil. There have been fish in this tank for about 6 weeks. As soon as the fish were put in, plant growth increased remarkably.


The second is another tank, which has only had fish in for a week, a total of nine gouramis and a Corydoras. While this tank was planted at the same time as the first, plant growth has been much slower because of the absence of fish but has already begun to increase.

Apart from six Ruby barbs in the first tank, all of my other fish (37 fish of 12 species) came included with second hand tanks, so not necessarily my first choice but I'm not complaining …......

So what I have concluded so far about those three “requirements” for a successful planted tank? Since my plants have grown very well :

Enhanced lighting? No. All but one of my tanks have basic T8 fluorescent tubes. New tubes I have bought from an online lighting supplier, Philips “daylight” tubes at £3 - £4 each according to size, about a third the price of “aquarium” tubes. but the plants don't seem to notice the difference.

Expensive substrate? No. My substrate consists of about 3 cms of soil from my garden, topped by 1.5 cms of gravel, with another 1.5 cms of sand on top of that. Neither the sand nor gravel are so-called “aquarium” types, but are “lime-free horticultural grade” from a local garden centre. I bought three 25 kg bags of each, i.e. 150 kgs total, for £20. I hate to think what my LFS would charge. They are genuinely lime free and the gravel, actually described as “horticultural grit”,  is of more suitable particle size than many “aquarium” gravels I have seen.

Extra Carbon dioxide? No. Fortunately Nature has provided us with very efficient, if underrated, CO2 generators. They are called fish. As I noted above, plant growth increased greatly after I added fish to these tanks. Some of this may have been down to enhanced nutrients, from ammonia and fish poo, but I think most of it is because of the CO2 since adding ammonia while cycling tanks seems to do very little to increase plant growth.

I have been doing about 10% water changes every fortnight, with a little vacuuming of the sand at the same time. I should say, of course, that I've had no problem with ammonia/nitrite/nitrate and have had no problems with algae either, glass scraping never required. I have kept to easier plants, and the more difficult ones would perhaps not do so well, but all of those I have tried have thrived.

Of course, the “look” of an aquarium is a matter of taste. In real life, my tanks do look a lot better, I think, than on the photos. For me, most tanks seem much too bare and open, too much like fish tanks and not enough like a piece of the natural world. Others will think mine look too much like a jungle and prefer the “garden” effect of aquascapers. As they say, “there's no accounting for taste”.

The tanks look great - totally agree that aquariums look better when well planted.

I set up a new 180l tank back in October which I've planted moderately - I'm really pleased with how it looks but I've also avoided any specialist equipment or the use of fertiliser and it does appear that it's kind of reached the limit as to how many plants I can keep healthily as a result. Some are beginning to struggle a little so it looks like I may need to start adding a bit of fertiliser now and then just to give them a bit of a boost. I think the lack of a bottom layer of soil is what I really needed.

I may be looking to setup a smaller tank (probably 30-60l) for the parents-in-law in the near future and as they're after something relatively low maintenance I'd be interested in trying the Walstad method. A such, I'd be interested to know whether you think this method would work quite so well on a smaller tank? It looks like natural fertilisation from fish is a key element but a smaller tank would obviously house only a small number of fish so could this be of detriment?

Also, would you mind saying what types of plants you've utilised?

Extra Carbon dioxide? No. Fortunately Nature has provided us with very efficient, if underrated, CO2 generators. They are called fish. As I noted above, plant growth increased greatly after I added fish to these tanks. Some of this may have been down to enhanced nutrients, from ammonia and fish poo, but I think most of it is because of the CO2 since adding ammonia while cycling tanks seems to do very little to increase plant growth.

I can think of two reasons for this: You are adding nutrients to tank in the form of food, and this passes on to your plants in other forms as noted. Secondly, in addition to the CO² provided by your fish, mature plants, ie plants that reach the surface, will provide CO² from the atmosphere.

Finally, you have to remember that plants provide CO² and consume oxygen during unlit periods.

Ooooh, now I'm going to be picky  Steve may the 'wrong place' police but I am the chemist. It's CO₂ not CO² 

No.  I've resigned! I did know about the CO²₂ thingy but... I didn't check my post before posting. A zillion and one apologies.

The plants that have done best for me are :
Stem plants
Hygrophila difformis and H. polysperma, both very fast.
Rotala rotundifolia ( a.k.a. R. indica)
Bacopa monnieri is OK but grows much more slowly.

Grassy plants :
Sagittaria subulata and Echinodorus tenellus.
Vallisnera spiralis has not done as well.

Amazon Sword, good in larger tanks but has hardly grown at all in the smaller ones. I'm thinking of trying them in pots

I inherited, in used tanks, Java Fern and an Anubias, which are growing fine on bogwood, but slow. Also slow growing are the Cryptocoryne, also inherited, not bought.

I originally set up five tanks like this, I'm just completing the planting of five more. This time I am also trying the red Ludwigia repens, fine-leaved Limnophila sessiliflora (like Cabomba but said to be easier to grow) and Hydrocotyle leucocephala. It's too early to comment on the performance of these.

I'll repeat what I have written before, I also like the floating plants Amazon Frogbit and Hornwort.

I don't think the size of tank makes any difference. Mine are 60 - 120 litres. A smaller tank has less fish, but it also has less plants which will need less nutrients. The Walstad method is really just the old idea of the balanced aquarium revived and updated. Her thesis is that the idea fell into disrepute because people were failing to grow plants successfully. She suggests that this is because most people rely on plain gravel or sand, which are not suitable for plant growth without additional nutrients etc. The "leap of faith" required is to take your nice clean tank, then put 3 cms or so of soil in the bottom before you do anything else. I was pretty nervous after spending a week setting up 5 tanks in this way. If things had gone wrong, it would have been a huge job to start all over again. In practice, things could hardly have been better.

I more or less did the "normal" method of cycling with ammonia, though I didn't stick too closely to the exact method. The plants had already been in for a few weeks and were well established before I started. At the end, I did have high nitrates, much as would be expected without plants, from which I conclude that most of the ammonia was being processed by the filter bacteria rather than the plants. I soaked up loads of "squished" water from an established filter into the new filter media, which is probably why the cycle was always quick.  Although ammonia and nitrates were both present in plenty during the cycle, the plants didn't grow any faster. It was only when I added fish to each tank that I saw an immediate rapid increase in plant growth rate. From this I concluded that it was most likely Carbon dioxide rather than nutrients that was the factor limiting growth.

My old chemistry teacher told us never to say CO₂ for Carbon dioxide as CO₂ only represents "one molecule of Carbon dioxide". 

Looking good Richard, how often do you have to prune the foilage.

Andy

Those tanks look fantastic. I'm sorely tempted to try this method with my next tank..... whenever that is!