Pond / water feature pump advice please

The pond is only tiny. I'd estimate about 400 litres, but I'll measure up and get a more accurate estimate before I buy a pump.

It's more of an ornamental water feature than a pond per se. The waterfall will be less than a metre high, and will be more of a gentle flow rather than a big gushing torrent.

I'm coming round to the idea of a mains powered pump. For the size I need I'd get change from 40 quid. I know this because I've just got back in from the pond shop, where I looked at some pumps. There is extra expense by going with mains, in that I'll need to invest in an RCD and an IP65 rated power box, but if I went with a low voltage pump I'd need a power adapter anyway, so probably not much difference in overall spend, but much more flexibility in terms of options.

As for fish, we had fish in our other pond years ago, but one by one they all vanished. Probably a cat's dinner.

 

I used black sink waste pipe.

 

You will probably laugh, but I pass the water through a black dustbin before it goes into the filter, a lot of the sludge falls out and sinks during the process, by the end of the season the dustbin it totally full of thick sludge.

 

@clueless, I dont blame you not wanting fish, I do find my goldfish a worry I could do without these days but not sure how to get rid of them humanely, they are interesting having said that.
I think far too many people put fish into ponds that are far too small to accommodate them.

 

No, I wouldn’t laugh. Koi keepers will often have a vortex chamber at the front end of their filter(s). It might be an idea though to empty the bin more than once a year

 

I've dropped a clanger.

Luckily we're early enough in the project to rectify it but I'm not 100% sure how.

The pond is dug. I initially filled it using an old tarpaulin as a temporary liner, just to test the levels and to settle the ground, but I've now drained it and removed the tarp. Proper pond liner is here, ready to be put in.

So here's the clanger. I completely failed to consider how much depth the pump will need, or how to hide it. The pond is only shallow. Less than a foot deep.

I have enough liner to go deeper if necessary, but we wanted it shallow.

Ideas please?

 

Yes, make a ‘sump’ to house the pump.

 

Deeper would be better, it wont heat up so fast so less algae problems, but the smaller the pond the worse the algae will probably be anyway.

 

I'd go so far as to say if it isn't deep enough to submerge a small pump then it is not going to be a very healthy pond.
It will quickly evaporate in summer and could easily turn stagnant because it will be too warm.

 

I'm not too worried about algae and such because as it's going to be an ornamental water feature rather than a wildlife pond, I have no problems occasionally changing the water. It's more the aesthetics I'm concerned about.

Other than the physical height of the pump, is there any rule of thumb about minimum depth for the pump to work properly?

 

Been working on it today. Absolutely cream crackered now. Here's some work in progress pics.

 

Looks good.

 

The first pic, which seems to have posted twice for reasons unknown, is using a tarpaulin to test the levels and settle the ground a bit. We left it like that for a few days, then yesterday I bucketed it all out.

Taking advice from you could folks, we increased the depth a bit today, and made an extra deep 'sump' where the pump will go.

Then it's ponder liner time with underlay.

The last pic is the liner mostly trimmed, and buried on two sides. The far side will be buried when we next have some time and energy. The right side is where the waterfall will go. I haven't worked out the practicalities of that yet.