Renewable Energy Monitor

I came across aquaculture, and - wanting to run the flood-pump from 12V rather than 230V mains - built this 15-min repeating timer to switch the pump.

The flood-and-drain pump controller. The components for this circuit mostly came out of my junk drawer, left untouched for 30 years.

With the 15-minute interval switch tested and working, I could take beginner's steps with aquaculture.

It's been fantastically successful.

I attached the 15-minute interval switch to a cheap 12V bilge pump and dumped the pump in an old parcel bin in which I store water for the garden.

An hour or so of messing around with cheap Tesco storage boxes, one-inch overflow pipe and tank connectors, a bag of pea gravel and a length of scrap garden hose and I had a working flood and drain system.

The first few minutes of hearing water gurgling out of the bottom of the gravel beds was a pleasure! But that was just the start.

I popped a water parsley and a water mint in while I tested the system's reliability. They quickly took advantage…

It's been producing tomatoes through summer and as we move into colder weather has a single chard 'perpetual spinach' plant that produces salad for one person every day. I've sown other chard seeds that have just started coming up.

Tomato plants simply placed on top of the gravel

The water started with an advantage - it was full of algae and the collected micro-life that accumulates in outside water. Nourishing! At least for plants…

Watching the system evolve has been educational. As life grew above the 'pond', I noticed aerial colonies of small midges hovering above the greenery, bouncing up and down in unison in the social dance of midges.

I guessed that the reason I started seeing more wagtails around this area of the yard this year is because the midges are providing them with food.

The water has steadily become cleaner has the plants' roots suck up the 'nutrients'. So much so that the whole set up is providing an opportunity to experiment with methods of keeping the water fertile.

The above pic gives an idea of the foliage produced by the single chard plant. You can just see one of the tomato plants to the left of the chard.

Summary: For a few hours of work, this has been the most food productive experiment I have tried. It's been cheap in terms of parts, in terms of labour, and especially in terms of maintenance. It's delivered food (and still is as we enter October), delivered much education about processing water, and it's enriched the 'wild' habitat around itself.

As you look at it, it's hard not to think about how to extend it and the positive impact it has.