ADDITIONAL NOTES
In order to maintain a relatively low tech aquarium several important issues need to be addressed:
Overview of Biological Process:
I am not a chemist nor a biologist so my understanding is limited but I do know the concepts sufficiently to gain results, and you can too. Here is a brief synopsis of the biological process in an aquarium. During the day it is necessary to have good lighting. At this time plants undertake photosynthesis producing (O2) oxygen and consuming CO2. Thus, CO2 injection is helpful and will enhance plant growth considerably. In my aquarium one can see oxygen bubbles from the plants rising during the day. At night only respiration occurs in plants, producing only CO2 (because photosynthesis requires daylight), so if you continue to add additional CO2 the fish can suffocate. Therefore, no CO2 should be introduced at night unless aeration is added at at night.
Lighting:
One can easily spend a bundle on a lighting system. However, I have found fluorescent T8 shop lights are most cost effective, and one can choose between one or two bulb fixtures to fit across the entire top surface of the aquarium. I have a total of 5-4ft bulbs on my 75 gallon tank. You can buy very expensive aquarium bulbs but I use inexpensive "daylight bulbs" which have proved sufficient.
CO2 (Carbon Dioxide) injection system:
I tried for years to have a freshwater aquarium system and raise plants, however, even with good lighting the results were marginal. So I first tried a very low tech but adequate system to produce CO2. This is based on beer or wine making. Take a half gallon soda bottle, fill it about 15% with white sugar, add a packet of bread yeast, and fill it with water to within 2 inches of the top and shake. Drill a hole in the screw on top and epoxy a 2 inch piece of standard aquarium plastic tubing on both sides of the cap to create an airtight connection. Attach aquarium flexible tubing to this plus an air-stone and submerge it in tank by weighing it down with a rock. It will start generating CO2 in about 6 hours. It is very important if you are using this method that you aerate at night otherwise fish will suffocate as a result of too much CO2 at night. This aerator hose and stone must be on a timer so when the aquarium lights are off you are aerating. I used this method for many years and it is totally adequate. The only downside is that it is exhausted in about 5 to 7 days and must be refilled. You can reuse the yeast dregs from the bottom on the new refill. After the CO2 injection depletes you will slowly start to see a reduction in plant growth. Actually this reduction can be a nice respite as large plant growth needs to be trimmed back every few weeks.
Eventually I became tired of maintaining this system so I purchased a CO2 tank and regulator from Harbor Freight. I also purchased a stand alone electrical solenoid valve plus another timer, which only allows CO2 injection during the day. This system is virtually labor free and a tank will last 6 to 8 months. Keep in mind that the more you rely on technology the more risk of something going arry, however, there is a lot to say for convenience with the CO2 tank. I would say that if you use the yeast method the most likely failure that could occur is that your aerator and timer could fail so you may wish to have two aerator systems working depending on the size and expense of your fish.
Timers:
Timers are readily available and are absolutely necessary to reduce your labor.
Automatic Fill System:
I have tapped into the cold water line at my bathroom sink using brass fittings and a shut off valve plus a brass pipe routed through the wall up to the tank. At the tank I convert to a plastic adjustable shut off valve as it is less likely to corrode. I adjust the drip into the aquarium to about one every second for my 75 gallon tank. That equates to about 5 gallons a day. It is hard to get it slower but if you can great. I have dripped a lot faster than this and have never seen any detrimental results. The slow dilution of chlorinated water into the highly organic tank has never been a problem in my 75 gallon tank. A very important note is that this inlet dripping into the tank cannot be immersed in the tank water as this could endanger the drinking water system if there is a line break and back siphonage occurs, instead an air gap must be maintained so that there is no possibility of it ever being immersed in the aquarium.
Reverse Siphon: (See diagram below for construction details)
What goes in has to come out. So the best thing I discovered for such a system is a reverse siphon to drain. I have two reverse siphons, one as a backup set a little higher. If I see the aquarium level is higher that means the first siphon has failed and likely needs cleaning. This is rare and not likely particularly likely if you screen the intake. Water from both these siphons discharge into a box behind the aquarium which gravity flows to the sewage system.
Aquarium Accessories:
In regard to rocks, you do not want limestone rocks or gravel in a freshwater plant tank. A basic granite or other multicolored gravel works well. One method of determining if you have a non-reactive rock or gravel is to put a drop of muriatic acid on it, if you see bubbles form you do not want to use it (please follow safety instructions for acid). I have about 3 to 4 inches of gravel in my tank as you need a good base for the plant roots. The system we are creating here is closer to a natural stream system which is generally more acidic and not basic like some african lake environment (no cichlid fishes in this system).
Filtration - Aeration:
If you read about filtration and aeration for natural plant aquariums you will see that many folks do not use any. The principal is that you want to have minimal agitation or aeration of the water during the day to reduce CO2 loss. The fish seem to do real fine as significant oxygen is also being generated during the day by the plants. I have an old under-gravel filter and I use it in my tank. Also I have a power-head that takes suction from the filter and I inject CO2 into this pump and the turbines break up the CO2 bubbles making for more efficient dispersion and lowers the volume of CO2 needed. I use a very low volume power-head for this purpose and inject the flow low in the aquarium so as not to create much topside turbulence.
Startup:
Add your rocks and city water and aerate for a days no need to add any startup chemicals or bacteria. Next you can get a little detrus and a couple of gallons of water from an established aquarium or pond that would be good but not necessary. Then add some hardy plants anacharis is good. A few gold fish I purchased mine for $.25 and stocked aquarium with them they were small and ugly and I introduced them to the pond and they grew up to be beautiful orange and white (see video). I like to introduce fish into my aquarium or pond slowly. I place the bag in tank to bring water to temperature of tank or pond then slowly dilute travel water with tank (pond) water in about an hour. Feed very lightly make sure all food is eaten in 5 minutes. Give the tank a couple of weeks then if you like you can return the goldfish to the store (don't expect a refund) and purchase your show fish.
Fish:
It is important to get fish that do well and do not fight each other in freshwater aquariums. I have two schools of fish each with about 12 fish, cardinal tetras and serpae tetras. They get along real well together both maintain their independent schools with the cardinals generally a little higher in the tank. I have had a number of live bearing fish produce young in my day but never egg layers but now the serpae's a number of times have produced a few young that have made it to adulthood. A great testimony for the well planted “natural” aquariums system.
Plant Nutrients:
You can take a sample of water to your local aquarium shop and they can test it for you. I have found that potassium and phosphorus are usually not a problem but nitrates are low. I purchased plant nutrients from an aquarium shop (high dollar) and it did boost the growth some. I did some research on the web and found that one can purchase potassium nitrate “Stump Killer” from the hardware store much more inexpensively and it has worked wonders for my plant growth to increase plant loving nitrates.
Automatic feeder and Maintenance:
If you you construct your tank as I mentioned above you will have a virtual maintenance free tank. Well almost. Every week you will need to remove the algae that grow on the front glass for visibility purposes. I use a large heavy duty magnet cleaner. Let the algae grow on the sides and back of the aquarium, remember you are trying to have a natural aquarium and this just adds to the biological system you are attempting to produce. You will also need to prune back plants every month or so. Eventually you will have a significant build up of detritus I reduce this build up annually. When this happens I use an aquarium siphon to clean the detritus that has built up in the gravel. After this cleaning I do see and increase in plant growth. I take a large 40 gallon trash can and use the siphon to clean the gravel where plants are not established. Simply submerge the siphon and hose, put your finger over it to close end of hose, then pull hose out of tank and place in trash can. Start vacuuming by inserting tube deep into gravel. The detritus rises and discharges to the trash can. Continue to do this until can is full. Then let the detritus settle for about 30 minutes and bail out clear water with a bucket back into aquarium. Don't worry about cloudiness in aquarium it does not seem to bother the fish and will settle and clear up shortly.
It is important to just watch the system to make sure everything is functioning as it should, but mostly you will not need to do much to maintain it.