Over the past six months I have been experimenting with the world of aquascapes – creating little underwater gardens in my tiny London flat. For someone in generation rent, for whom outdoor space is at a real premium, but who also wants to get a horticultural fix year-round, these underwater gardens turn out to be a pretty perfect solution. Shrunk down into miniature, they give me lush little landscapes that I can spend hours tending to: a piece of the Amazon or Borneo where it is forever summer even in the darkest days of winter.
It seems I am not alone. A single picture I posted of one of my experiments, to my great surprise, racked up over 160,000 likes on Twitter within just two days, along with literally hundreds of questions from people eager to give it a go. Number one on that list was how I keep the water in my little ’scapes clear and algae-free. So to help fellow budding aquascapers I thought I’d give you a quick overview of what works for me.
The growth of algae in tanks is essentially powered by three things: light, carbon dioxide and nutrients. So the most effective way to curtail their populations is simply to control these three factors. Fortunately, the very plants you are trying to grow will do this for you automatically, aggressively competing with the pesky algae for their very means of survival. As a general rule, the more densely you plant your tank, the harder it is for these underwater weeds to get a foothold.
To further limit light availability, I only keep the tank lights on for six hours a day (I use regular desk lamps fitted with inexpensive LED grow bulbs). A cheap timer from any hardware store means this is kept constant even when I am away travelling. Aside from these, my tanks have no pumps, filters, thermometers or heaters. Basically zero tech. I just rely on plants to do all the work for me naturally.
Other than planting, the easiest way to control nutrient levels in a tank is not to introduce them in the first place. The number one source of these is fish. Both their waste and uneaten food can provide a veritable buffet for these watery weeds. For me it’s all about the plants so I keep fish numbers to an minimum. Far from being boring, having to hunt for a glimpse of them is far more fun than a massive shoal on permanent display.
Otherwise, there are equally fascinating critters that can actively feed on algae, acting like little biological hoovers sucking up the green stuff while leaving your plants alone. These are tiny freshwater shrimp, which come in a dazzling range of colours from Avatar blue to stunning crimson and white-striped beauties, all of which grow no more than 4cm long and can be kept in the tiniest unheated tanks.
Finally, as even the best-managed tanks can slowly accumulate nutrients, I do a simple water change once a week. This can sound daunting, but simply involves me taking a mug of water out of the tank each week and replacing it with a mug straight from the tap. That’s it.
Email James at james.wong@observer.co.uk or follow him on Twitter @Botanygeek
