Spraying with the garden hose has to be done daily and eventually they slowly go away. Here is a portion of a ponding article on aphid control from another forum that should help. (Aphids can easily be sprayed off of your aquatic plants with a good spray of water from the hose which will knock them off the pads of your lilies and lotus. While this method is one of the most effective you need to be diligent to keep up with it every day until you notice they are gone. The aphids will soon learn that the location they have chosen is not to their liking and they will eventually stop returning. Many of the ones you are able to spray off the pads will also drown but these critters are very light bodied and can walk on water so you will need to keep up with the spraying. Another really effective method is by manual removal. If you have an all out infestation you can remove all the affected pads and throw them out. Your waterlily will grow back new pads and will be no worse for the ware. I would not recommend this with lotus or other aquatics however. Lotus can drown if you remove the pads prematurely or you could kill the whole plant. Another type of manual removal is what I call the "Squish method". If you happen to be squeamish you can wear a pair of rubber or latex gloves. The final method I use is my home made Aphid Spray. ***Warning*** Do Not spray on a windy day to avoid getting solution in your eyes and do not spray when the sun is out. The sun will magnify through the solution and burn the pads. Only spray in the early morning or at dusk. This recipe makes one litre or two pints of solution. Mix 1/8 cup of 10 Volume Hydrogen Peroxide, 1/8 cup of Rubbing Alcohol and 8 drops of Phosphate Free liquid dish soap. Top with water to make two pints or one litre of solution. Fill a spray bottle with the solution and spray your affected plants until the aphids are completely drenched. Leave the solution on for 30 minutes and then rinse off thoroughly. This solution is safe for use with fish but I would recommend removing the affected plants if possible during treatment. The Rubbing Alcohol evaporates quickly so it will not cause any damage, The Hydrogen Peroxide will provide elevated oxygen levels in the water during treatment so it also does not cause any damage. Some dish soaps still contain Phosphates so you should check the label on your soap before using in your pond.)

Anacharis, dwarf hair grass, alteranthera (pink and purple), african fern, java fern, amazon sword, micro sword, red & green tiger lotus, 7 different aponogetons, hornwort, cabomba green, watersprite, moneywort, rotala rotundifolia. And some other crap I cant think of at this time. Trace elements are more important then ferts. As long as you dose correctly your betta will not mind. CO2 injection is a big help. A product like flourish excel will help greatly also, to put it simply it is a source of organic carbon that can be used instead of CO2 injection or along with it. I like and trust flourish products. Lighting is also important, correct color temp., or Kelvin rating, helps. Between 5800K and 8000K is ideal, lab studies showed that 6700K is optimum for freshwater aquatic plants. Intensity is important also, 2 watts per gallon fluorescent lighting of correct color temp. for low and some moderate light needing plants. 3-4 wpg for some moderate and high light required plants. Tricky part is after 2 to 2 1/2 wpg you should have some sort of carbon source or CO2 injection or your asking for troubles (algae, pH flucs and so on). Substrate should be "micro gravel" for most plants, at least 50% "florite" will really help root feeders. Try the link below for some good info.

Sky, I grow mine in a pot with no drainage. I leave at least an inch at the top of no soil so I keep it soaking wet. That way I can have it in a inch of water. I also give it 1 tbl of epsom salt in a gallon of water once a month. I have it in morning sun. Which I am sure is not real sun compared to your zone. In your zone I would probably keep it in the shade. If you do these things I think your browning will stop. I have also grown Pink Sunburst and Tropicana in bog condition. The hotter it is the more water it seems cannas can take. If you doubt this wet process for this plant check out Bernie here in the Canna forum. http://forums.gardenweb.com/forums/load/canna/msg0814564325672.html

Hey, I can trade you some more colors of irises for the Pink oriental lily. If not interested in that, I have some other bulbs too, Cannas, and a small Bamboo for the pond. Maybe a small water lily. Probably some other stuff too. I have a small pond similar to yours. where do you live in Upstate SC?