We'd had this five foot deep 3000 gallon koi pool which I built myself for 32 years, but in April it developed a serious leak.
To replace the liner would have been a major job. Not only would all the perimeter rocks have to come up, so would part of the waterfall and the bridge over the filter return.
So we decided to have it filled in. It took the contractor 20 tonnes of hardcore to fill it.
The surface was paved to the level of the original pool
The koi went to a good home, a neighbour two doors away with a similar koi pool, "they are living happily ever after," I'm pleased to say.
and we bought a Marinelli fountain.
The fountain sits on a round concrete paving slab
on top of what was this.
a 40 gallon pump sump, (a plastic water butt set in concrete) connected by a 4" pipe to the pool's bottom drain.
Before the pool was filled in. I drilled several 1" holes through it's sand and cement screed base into the subsoil. Also one through the bottom drain and the encasing concrete. so water that fell on the new paving would be able to drain away. Our soil is a bit sandy so free draining anyway. I blocked up the connections for the filter pump, drain pump and waterfall bypass from inside the sump. I pumped out the last few gallons of water below the level of the sump's purging socket.
Using one of the mains supply cables that fed the pumps I connected up a 13amp socket and the fountain's transformer to the wall of the sump (a plastic water butt set in concrete), ran a cable through a hole in the paving stone to the fountain and turned it on. It worked fine.
Everything continued to work without any problems for several weeks. There was never any standing water on the new flags.
Now we don't often have the fountain on. But Thursday night of last week, I'd been pottering arond in the garden and decided to go indoors around 8.00pm. I thought I'd just check out the fountain. It's usually turned on by one of the four switches behind the lounge curtains that control the lights in the garden, but I can bypass it from the garage, on which circuit they are all on. I switched it on and everything in the garage, shed etc., tripped out. So I unplugged it, re-set the RCCB and everything else came back on again.
I had my suspicions. So I decided to tackle it then and there as heavy rain was forecast for the next day. So I dragged the fountain (all 156 pounds of it) off the stepping stone and took a lump hammer and bolster chisel to the mortar securing the stepping stone and took it up.
As I suspected, the sump was full of water and the socket and transformer under it!
I pumped out all the water with a wet and dry vac and removed the socket and transformer. I then noticed more water was still steadily coming into the sump through the holes I'd drilled in the side of it to secure the socket and transformer. I concluded that water was coming up from the ground below the bottom drain, five feet down, because of the height of the water table, through the hole I drilled in it and between it, the concrete encasing it, the 4" pipe and the sump. When concrete goes off, it shrinks and leaves enough of a gap for water to seep up, if it can get in.
So I blocked up the screw holes in the side of the sump with mastic.
I decided not to risk having mains in the sump and cut off the low voltage wire to the fountain.
I mounted the transformer (fortunately, they are waterproof) in the garage next to one for a low voltage spotlight and plugged it into the fountain's socket.
I drilled a new hole through the centre of the stepping stone and pulled the cable up through and connected it up to the cut off wire to the fountain, as it was now providing low rather than mains voltage. I was able to get this small connector in the small space under the centre of the fountain's base.
I replaced the stepping stone and dragged the fountain back on.
I filled it up turned it back on It was now 9.30pm. That was enough for one night.
The base was still to be repaired.
It's worked fine ever since.
I just put a removable bung in the redundant hole in the stepping stone. I've pushed a cane down it several times since and despite all the rain we've had, the sump has stayed dry.
I re-made the base on the Saturday. I've since darkened it down a bit to more or less match the fountain.
This was the way I was originally going to do it, but the supplier said if I cut the pool's cable, it would invalidate the guarantee
Now I don't care, it's working.
