Header pond being syphoned out when waterfall pump is switched off

[Marqu15]

Hi, I need some advice please, there are 2 ponds, the smaller one has water pumped to it and it returns to the lower pond via a waterfall, I have just relocated the top pond to a higher position, I had to remover the filter / uv box as there was nowhere to site it and everything is fine whilst running, however, when the waterfall pump is turned off the water in the higher pond is syphoned back down the pipe, leaving the top one empty.
I would have thought the pump had an anti syphon function but apparently not, I could solve this by raising the feed pipe at the top from below water but then water would gush everywhere, can I fit anything to the pipe to prevent the syphoning occurring? looking for a simple and cheap fix if possible please?
Thanks in advance

 

[mrsclem]

You need to install a check valve to keep it from back flushing. You could also drill a small hole in the line right above the water level in the top pond. When the pump shuts off, air will enter thru the hole and break the suction. I personally have not had good luck with check valves so have gone with the hole in the line method.

 

[Marqu15]

Thats a great idea about drilling a hole and I will give it a try, many thanks for taking the trouble to give advice.

 

[mrsclem]

No problem, glad to help. That's what this forum is all about!