Are these rocks ok for bog edging?

[CarlaSee]

I have an established pond that's at least 8 years old. Over the last 2 years I've had trouble keeping the water free of algae. I have a ledge in the pond that is 10' long, 1' wide and about 14" deep. I plan on putting a bog filter there and everything I've read says to put porous rocks for the EDGING. I have photos of the rocks I'm thinking of using but I want to make sure they are safe to use in a koi pond. I also am going to lay the manifold at the bottom before putting the 3/8" pea gravel on top of that so that the water will flow back into the pond. It will be a very small "waterfall" but my main focus it to keep the water clear. My concern is; because the space is so precise, (limited), I need to use rocks that will be stable but won't take up all the room, won't cut the fish, and will hold the pea gravel and plants securely. I've also attached a photo of the ledge in my pond. It's hard to see because it is very overcast here and has been raining. Any advice would be appreciated.

 

[CarlaSee]

I have an established pond that's at least 8 years old. Over the last 2 years I've had trouble keeping the water free of algae. I have a ledge in the pond that is 10' long, 1' wide and about 14" deep. I plan on putting a bog filter there and everything I've read says to put porous rocks for the EDGING. I have photos of the rocks I'm thinking of using but I want to make sure they are safe to use in a koi pond. I also am going to lay the manifold at the bottom before putting the 3/8" pea gravel on top of that so that the water will flow back into the pond. It will be a very small "waterfall" but my main focus it to keep the water clear. My concern is; because the space is so precise, (limited), I need to use rocks that will be stable but won't take up all the room, won't cut the fish, and will hold the pea gravel and plants securely. I've also attached a photo of the ledge in my pond. It's hard to see because it is very overcast here and has been raining. Any advice would be appreciated.View attachment 138364View attachment 138365View attachment 138366

 

[mrsclem]

I saw in your other post that you have koi in your pond. How many and how large are they? A bog is a great way to improve filtration in your pond but it sounds like you are planning on turning actual pond space to bog. That is going to decrease your pond volume. Can you add on a bog outside of your pond? 700 gallons is small for koi and making it smaller may lead to more problems.

 

[CarlaSee]

Yeah, you're right and I hadn't really looked at it like that! I have about 10 Koi in total. 4 are about 16" and the rest are 5" and smaller. I have another pond that is "in-ground" and probably about 1000 gallons, that I've been working on so that I can move my smaller Koi into it. I was putting in an external bog filter for that one but when I noticed my smaller pond wouldn't clear up with 1/3 water change I started to worry, which redirected my attention to "fixing" that problem asap. That's how my mind works lately...scattered! I'm the caregiver for my husband and my ponds are MY caregivers Anyway, I can add a bog outside of my smaller pond probably just as easy as trying to add one inside it. I appreciate the advice. It's very nice to have some to bounce these choices off of BEFORE I make a final decision!

 

[CarlaSee]

I just recalculated my smaller, partially above ground pond because it's been a few years since I've done it. The following is what this very hand website calculator said... I wish I had this calculator years ago! Because this sites gives the surface area I now know the size to build the bog for my inground pond AND I can easily figure out how big to make and exterior bog for the pond in the above conversation.

Result
VOLUME: 1 346.49 US gal
SURFACE AREA: 60 ft²
LINER SIZE: 18 x 14 ft
PUMP SIZE: 673.247 US GPH

 

[addy1]

Porous can be any stackable rock that allows some water to drift in and out of the bog area.

I don't have koi, not a expert, but it appears your pond is a bit small for koi.

 

[poconojoe]

Good luck with whatever you decide.
Keep us posted.

 

[Lisak1]

A bog edge can be many things... I've never read that it needs to be porous rock, so maybe that's more the weeping wall effect. My bog feeds a small pooling area which then feeds my big waterfall.

Many different approaches one can use - any time you read that you MUST do something, move on. Ponding is full of choices!

 

[poconojoe]

A bog edge can be many things... I've never read that it needs to be porous rock, so maybe that's more the weeping wall effect. My bog feeds a small pooling area which then feeds my big waterfall.

Many different approaches one can use - any time you read that you MUST do something, move on. Ponding is full of choices!

Yep, my separation wall is not porous, it's covered with liner and in the center I made a low spot for the water to return to the pond.

 

[addy1]

Mine is also a solid wood wall covered by liner. With a 3 foot opening for the water to return over a flat rock.

 

[GBBUDD]

maybe that's more the weeping wall effect.

Yea the air driven bog use the permeating walls. Don't realy see the point

 

[GBBUDD]

PUMP SIZE: 673.247 US GPH

I would lean toward a stronger pump on smaller ponds I think it's better to filter at least once an hour turn over.

 

[CarlaSee]

The 4 koi that are now 16" I've had since they were babies. Now that they are so big I have put an inground pond in. I'm working on putting in ledges, edges, and a bog filter for it. I will then move them into it. The pond they are in now is definitely too small for the big ones AND the smaller ones, therefore the move.
VOLUME: 1 346.49 US gal
SURFACE AREA: 60 ft²
LINER SIZE: 18 x 14 ft
PUMP SIZE: 673.247 US GPH
Thanks for the advice on porous or nonporous! It makes the choices easier when it isn't a MUST do thing as Lisak1 said!