What's the best bog gravel depth?

[jgell]

What is the best depth for gravel in a bog filter? I'm using reservoir blocks and on top of them I was thinking 8" of 3"-5"(5"-8" if I can find it) river rock, then 8" of 1"-3" and then 8" of 3/4". What works for you guys?

What is the minimum gravel depth you go with? The reason I ask is because my wife is not liking the height of the build up of the bog edge and easiest way to reduce that would be to shave off from the top. The bog is dug and the bottom is leveled and I don't want to dig it out any deeper.

 

[mrsclem]

I use 24" of pea gravel- simple, basic but it works!

 

[brokensword]

I've multi-layered as you're doing; my numbers are--

12" of 8" round rock
12" of 2" cobble
12" of 3/8 pea gravel.

In your above, I'd swap out the 3/4 for the 3/8 pea gravel, were it mine.

 

[combatwombat]

I think anything over 12" ought to do fine. Deeper is probably better until you get to about 36", and then it could start becoming an issue. Lots of people with very successful bogs that are 12" of pea gravel and that's it.

 

[poconojoe]

There doesn't seem to be any "best" gravel depth.
If you read throughout the web, the suggested gravel depth is at least 12".
You can go with more, many have gone much deeper, but I would suggest at least 12".

 

[jgell]

Thanks again for the info. We have compromised on a total of 18 inches of gravel.

 

[addy1]

Mine is 2.5 feet deep of pea gravel, works great

 

[poconojoe]

Thanks again for the info. We have compromised on a total of 18 inches of gravel.

Sounds good.
Mine has been running for a year and a half non-stop (even through the Pennsylvania winter) and it's doing great. As I said, it's 12" of river stone. The bog is 14 feet X 5 feet. The surface area is just over 30% of the pond's surface area.
I have two 10 foot long 2" pvc pipes with slits cut in them under the river stone as my distribution manifold.

 

[teckpham]

My first bog is 12" pea gravel. Work great for the last 2 years. The new one I am working on now will be 16".

 

[GBBUDD]

@jgell You have the right idea final product though most will agree is 3/8" pea stone i did 3/8" river and 3/4 river rock as a final . But you also quite a few of the answers you got were from folks who do not have aquablocks but only have pea stone gravel bogs with a perforated pvc pipe . so be careful in what you take as a similar set up. I too have aquablocks and from seeing that some roots can grow 18" thats what i look at as a minimal depth above the blocks with a minimum or 12" of the 3/8 or 3/4 river rock and or pea stone

 

[teckpham]

@jgell You have the right idea final product though most will agree is 3/8" pea stone i did 3/8" river and 3/4 river rock as a final . But you also quite a few of the answers you got were from folks who do not have aquablocks but only have pea stone gravel bogs with a perforated pvc pipe . so be careful in what you take as a similar set up. I too have aquablocks and from seeing that some roots can grow 18" thats what i look at as a minimal depth above the blocks with a minimum or 12" of the 3/8 or 3/4 river rock and or pea stone

Yes, my bad. My are only using perforeated PVC pipe.

 

[addy1]

Yes, my bad. My are only using perforeated PVC pipe.

Mine is just perforated PVC pipe, slits cut with a saw, slits facing down. Still doing fine 10 plus years later.

 

[GBBUDD]

I have both but to answer your question I would lean toward 18 inches as a minimum so no matter what you plant the roots don't get into the pipes and clog and reduce water flow.

 

[poconojoe]

I could only get river stone when I built mine. Not many places were open due to Covid (May, 2020). The local mason supply was closed. I found a garden center that had the river stone.

I cut slits in my 2" pvc pipe 1/3 through and spaced at 1-1/2" apart. I faced the slits up, unlike addy who faced them down. I'm not saying facing them up or down is better, just a matter of how you look at it. You decide.

 

[GBBUDD]

and spaced at 1-1/2" apart.

INCH AND A HALF OR WAS THAT A FOOT AND A HALF?