As I guess you are discovering, keeping plants is far more difficult to do right than keeping fish. You do not have much $$$ to spend and this exasporates things.
It is quite 'easy' to set up what is called an EI or Estimative Index tank and bung in whatever plants you want into whatever substate you want. The way EI works, in a nutshell, is to just give plants EVERYTHING they need and hey presto they grow like nutters. You give them LOADs of the right kind of lighting (and I mean loads). This is the driving force for massive plant growth and this then means massive nutrient take up needed, so you give it to them: Pressurized CO2 and daily, carefully measured amounts of plant food (fertilizers) dropped straight into the water (this is called 'dosing the water column).
This method as you can see, requires loads of $$$ and a LOT of maintenance, BUT you can basically grow what you want. The EI method is a brain child of an American chap called Tom Barr, aka plantbrain (search him out):
http
/www.fishforums.net/index.php?showtopic=189932
Majority of 'prize winning' tanks use EI, an to be frank, some of these tanks are absolutely staggering:
http
/showcase.aquatic-gardeners.org/2005...vol=0&id=17
http
/showcase.aquatic-gardeners.org/2005...vol=0&id=71
For a brilliant example of 'never done it before' to 'staggering set-up' follow the astronomic rise of fellow forum member Dave Spencer's setup here:
http
/www.fishforums.net/index.php?showtopic=174628
http
/www.fishforums.net/index.php?showtopic=194136
If this is the route you want to go, then let us know. Expect to be spending upwards of £500...!
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The other end of the scale are what are called 'El Natural', a method founded by a lady called 'Diana Walstad' - she wrote a must-read book called 'Ecology of the Planted Aquarium'. Her idea is to provide a 'natural' environment for both Plants AND fish. Plants readily absorb Ammonia, Ammonium, Nitrite & Nitrates, i.e. fish waste. Fish poop is a great substrate builder too. So the Fish feed the plants, the plants keep the fish happy by gobbling up all the crap! The cycle of life shall we say is balance in an el Natural tank.
These tanks rely on lower lighting set ups -> this therefore minimized rapid nutrient take up by the plants as basically all nutrients came from a well founded PROPER substrate and fish food (that is 'processed' of course by the fish). CO2 should not therefore be a problem espcially if what is called 'ariel' or 'emergent' growth is encouraged: Basically CO2 is a right royal git to get into the water. It is expensive / difficult to produce (either using yeast based fermentation DIY kits, or using bottled, pressurized CO2) and once available, not easy to dissolve into the water (hence diffusers / unsightly CO2 ladders). If the plants are encoraged to grow OUT of the water, hey presto, CO2 freely available to the plants (in the air, as is the case for normal land based plants) and hence no mucking about with CO2 injection.
Creating an 'El natural' setup is NOT easy and is a leap of faith: Minimal water filtration, low / no maitenance - that is to say a 'dirty' tank is encouraged somewhat - no substrate vaccing, reduced choice of plants (those that are OK with lower lighting levels), you need a lot more nounce to create such a set up.
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Personally I have combined the two ideas into a kind of hybrid tank and has been going very well for 1.5 years now, is extremely low cost / low maintenance and long-living fishies. Plant growth is medium - I prune out a handful of greenery every other week or so. Conisdering I rarely do water changes (TBH, I just top up the water) and rarely vac, the substrate remains clean, the water is crystal, the plants grow. See my small pikey little 60L set up here:
http
/www.fishforums.net/index.php?showtopic=220341
GL with keeping plants with whatever route you go. We are all here to help if needs be!
Andy