Friday, May 14, 2010

Small Problem - Losing water on the drain cycle

OK, so flood/drain is definitely working out well for the plants, and I'm pretty sure that the fish like the bubbles when they kick on. It reminds me of Finding Nemo ... "bubbles!!!"

However, and this may be a problem unique to my set up, the cycling is causing me to lose water, and the equilibrium level of water is less than optimal. Here's what's happening...

In my pond, I have a skimmer with the pond pump at the bottom. The idea behind the skimmer is obvious - it allows you to catch stuff floating on the top before it sinks and then gets sucked into the pump. Now, whether that works as well as it should is another matter that I don't want to get into here. At the back of the skimmer is an outlet for the electrical cord from the pump to go underground to the outlet. There is also an overflow outlet that goes out the back, travels on a french-drain like gravelly-path to a small pit that I dug underground and lined with gravel and sand. This works quite well for keeping the pond from overflowing.

Here's the catch, though. While the pump is pumping, the 3 tubs with plants are filled with water. When the pump shuts off, that water drains out from the tubs and into the pond, raising the water level. When the water level reaches the overflow drain, the water flows out of the system.

I am most comfortable with the water level when it is just below the level of the drain, but as you can see, this is not currently possible for very long. Every time the tubs drain out and the water level comes up, I lose water until the maximum water level (when the pump is off) is below the overflow drain.

What I need is a way to automatically seal the overflow when the pump kicks off - or, better yet, seal the entrance to the skimmer. This way, the pond can handle the extra water, as there's plenty of space in the pond before it overflows.

If not that, I need to re-engineer my overflow so that it can somehow store the water while the pump is off and the level is higher until the pump kicks back on and it can handle the additional volume.

Any suggestions?


Mike said...

Can you add a 'sump' tank to the system the size of the water volume of the 3 grow beds? The grow beds flow directly into the sump instead of the pond.

Set up the drain from the sump on a float valve so that when the water level drops in the pond, the sump water drains into the pond. When the pump turns on, and the pond level drops, the water will flow back into the pond from the sump.

Add an overflow from the sump to the pond so if the float valve sticks or it rains hard and the grow beds collect enough water to top the sump off, it flows back into the pond.

Now, if there truly is too much water in the system, it will overflow the skimmer and leave the pond.

Brian Naess said...

I could add a sump tank, I suppose... Not sure where I would put it. It would have to be pretty big and lower than the veggies yet above the pond to avoid having another pump. I'd have to cover it to prevent mosquitoes...

But yes, that's a good idea! I'm going to have to think about it some more.

I'm thinking about trying to put in elbow fittings in the two holes in the skimmer to effectively raise it up a bit. The hole for the wire is a bit higher already, so it just might work.

Of course, that doesn't really fix the problem, but it does allow for a slightly higher water level in the pond, which would make me happier!

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