This complete revision of the previous posting is meant to address the questions and comments I received, as well as add new information I have stumbled upon since then. The one big change in the method is the use of potting vermiculite in the lower substrate layer with the soil, rather than sand. This soft material resists becoming compacted quite well.
The method outlined below has grown beautiful aquatic plants for me with a minimum of cost and maintenance, and I believe it is repeatable. I originally tried it on a 10 gallon which had done poorly for 1.5 years which had gravel-over-peat substrate, CO2 and micronutrient fertilizers, and no substrate aeration (actually Crypt. affinis and Ludwigia repens had done OK, and all others poorly). This time I used vermiculite mixed with Yolo loam (a local silty loam) on the bottom, covered by #3 sand. I pushed pieces of the pond lily tablets into the substrate (both the loam and the lily tabs were suggested by Tuan Nguyen, a former UC Davis student).
This tank was exceptional right from the start. A pitiful group of E. tenellus literally exploded into a grassy field, with runners shooting out all over the place. It looks like a small patch of the E. tenellus field in Amano's book. This was encouraging. A pitiful Nymphoides aquatica which I moved from the dying 55 gal. immediately put out giant underwater leaves like those pictured in Schuermann's book (2.5" in diameter is the biggest). L. repens shot up with HUGE leaves, requiring frequent pruning. Except for the 1st month after setup, there has been no visible algae. This was my best tank yet. (I should mention also that the nitrates measure zero no matter how much of the pond lily tablets I have pushed into the loam).
The only thing that still is a minor nuisance for me is algae. Some of my tanks are algae-free (none visible whatsoever), but the higher light tanks still have some algae (though not a big problem). I am currently following some leads for algae control based on DIY phosphate-limiting agents which are cheaper than the "Phos-Sorb" type resins. This is based on the ideas in my previous post on soil chemistry, which I will post the relevant sections of immediately following this post. The soil chemistry is more technical, but the suggestions below are meant to be self- contained.
(I should mention that it seems to me that substrate aeration is not needed for the tanks that I set up, but they are all fairly young. The two-level substrate I use seems to allow an aerated space on top with lower nutrients and a rich, fine grained low aeration section on the bottom for those roots which care to penetrate. I have noticed that fine Crypt roots stay in the upper layer, and grow just fine there.)
Jim Kelly jkelly@landau.ucdavis.edu
The problem is that there are very few good references with correct and essential information, and that pet shops that sell the plants do not know how to keep them alive and spread false rumors. Some pet shops even sell terrestrial houseplants for aquaria because, "the true aquatics always die and the terrestrials don't decay for a much longer period of time, so customers are more satisfied." (An employee actually said this to me in a low whisper once.) Pet stores are generally the worst place to look for help (I'm sure many exceptions exist, but I haven't found any yet), and aquatic plants books give very little useful information.
The only place with truly outstanding information at the time of writing is the Internet. If you're a student with an Internet account, find out how to subscribe to the newsgroup 'rec.aquaria', where you can ask questions to the best people in the world who grow aquatic plants and keep fish.
Even better is the World Wide Web site that you can reach on Mosaic at the address 'http://www.actwin.com/fish/'. Ask your computer friendly friends how to use Mosaic. This site contains the best postings from the aquaria newsgroups from the past, and is where I got most of my info, and elaborates extensively on what I say below. IT IS THE ONLY PLACE TO CURRENTLY GET THE NEEDED INFORMATION (that I know of)!
With this information you should be able to grow plants better than 99.99% of people that ever try to. You may have to buy a few low price items, and mail order places are usually half the price of retail pet stores and carry a larger selection (see the CHEAP ITEMS section below). Here are my humble remarks on the cheapest way to cover the most important bases for planted aquaria, which have resulted in very lush planted aquaria.
Hopefully you won't need good luck, but I wish you it anyway.
Jim Kelly.