Sunlight and aquarium plants

In the #73 issue of Aquatic Plants Digest, Stephen Pushak discussed the placement of aquaria in sunlight and wondered how it might affect 
plant growth.

I have a relatively small cube tank (19" X 19" X19") in a West-facing window of my apartment. It receives sunlight from early afternoon 
until sunset every day. Being on the 22nd floor of a high-rise, there are no obstructions outside of the window to block the light 
reaching the tank.

Algae can be a problem, but is easily solved by restricting the nutrient level in the water which algae require to grow. I do this by 
using RO water and by not over-feeding the few fish that are in the tank. Frequent water changes with RO water keeps the Nitrate and 
Phosphate levels low, limiting the growth of algae.

The main attraction of the tank is a dwarf tropical water-lily which is planted in a pot placed inside the tank. I feed the lily with one 
SERA Florenette T tablet each week, placed into the gravel of the pot. The water-lily started to bloom on January 2nd, and has 
consistently sent up at least one new bloom every day since. It was quite a sight in the dead of winter to see a blooming water-lily 
against a backdrop of the snow blanketing my view of downtown Toronto.

The tank also has a piece of driftwood to which I attached a portion of Java Moss. The Java Moss exploded and has to be kept constantly in 
check but I have not had to contend with hair algae overgrowing it, as I have seen in less well-lit tanks.

As for George Booth's recommendation that philodendron roots can remove excess water-soluable nutrients, I have a seven foot high jungle 
that can underline his point. I placed a couple of cuttings of philodendron in a plastic mesh pot attached to the upper rim of the tank. 
Most of the maintenance required by this set-up is related to pruning this monster back so that it doesn't take over the room.

The only drawback to the sunlight seems to me to be the possibility of overheating the water, especially in the summer. Careful use of an 
air conditioner has allowed me to keep my maximum water temperature below 80 degrees at all times of year.

So for anyone with an available window who would like to try using sunlight to light their tank, go for it. Just remember to keep a 
careful watch on the nutrient levels in the water (keep 'em low) and the temperature of the water (steamed water-lily probably wouldn't 
taste very good).

James Purchase
Toronto, Ontario
jpp at inforamp_net