Under gravel suction grid.

[Lesley Gilks]

Has anyone had an under gravel suction grid installed in one of their ponds and how well did it work? I'm in the process of digging out the pond...I'm going for an active bog filter and came across this as a complimentary filtration system. I used one in my aquarium and was always pleased with how it worked but wondered if there were any draw backs. I've seen it used with an air pump to lift the water through the gravel bed but was thinking about a pump as I want to also have a waterfall/stream as well.

 

[Lisak1]

I have seen videos of under gravel grids installed in CA ponds - the Pond Digger has posted a few of them. I don't know if they are up flow or down flow systems though. I've been curious about them myself. One thing I wondered about was the potential for clogging, if you were drawing water down through the gravel.

 

[Lesley Gilks]

It's a down-flow system that then is pumped to you filtration. I saw the same video and in one of his Q & A sessions he says that you need to run the water fully through the grid once an hour. In other videos, they say it's efficient and you don't need to do a yearly clean on the gravel. I suppose if there is enough oxygen, it will break down any organic matter and would work the same way as a bog filter, it's your pre-filter so to speak. It makes sense to me. I don't know how you would install a skimmer into the system unless you used a second pump but then it should work the same way as a skimmer.

 

[Stephen Noble]

Here is a link that you might find helpful: https://issuu.com/pondtrade/docs/1805ptissuu/43

 

[combatwombat]

Lesley, did you end up building this? I am investigating a similar solution, using an air lift pump to suck water through the grid and return it via a jet at surface level.