Hi all,
one other thing i find with having plants is they will indicate to you very quickly when your nitrate levels are increasing by showing rapid growth and a darker green to their colour..
This was the idea behind the "
Duckweed Index", basically you use the growth and colour of the plants as an indicator of the nutrient status of the tank water.
I chose a floating plant to take CO2 out of the equation.
There were a number of disadvantages to Duckweed, as well as the obvious one that it gets everywhere, it also doesn't grow very well in soft water, and it needs a reasonable level of nutrients to grow at all.
After a bit of trial and error I found that Amazon Frogbit (
Limnobium laevgatum) was the perfect "duckweed". Frogbit will survive in very low nutrient conditions, and shows a rapid response in both growth and greenness when supplied with nutrients.
You can increase oxygenation by causing water turbulence at the surface [Amano does this in his planted tanks at night to prevent fish deaths] or you can add a Mazzei venturi or have a needle wheel pump [they can add between between 300-900L/H of air] just before your return pump
These a good suggestions, I always recommend the "Amano night-time air pump" to CO2 users to rapidly out-gas excess CO2, and if I don't have a "wet and dry filter" I like a venturi device on the external/internal filter outlet.
For low tech keepers, both planted and non-planted, lots of flow is a
win, win situation, as it continually replenishes oxygen, and replenishes, or out gases, CO2 when it has been used by photosynthesis or built up due to respiration.
I'm definitely not saying that you can't maintain aeration and water quality in non-planted tanks, a lot of people can and do, but plants buy you some "wriggle room" for when circumstances mean that you can't spend as much time with he tanks as you would like.
If people are interested in this sort of area I'd recommend, <"
Aeration and dissolved oxygen .....">. I wrote it after talking with a number of plec breeders and keepers about unexplained plec death (notably the much missed Bob Marklew "macvsog23"), and it was based upon these conversations and my experience working with the re-mediation of landfill leachate, as well as my own fairly amateur fish keeping.
cheers Darrel