Bog filter in climate with freezing winter temperatures

[BeginnerMind]

I'm going to install a small goldfish pond this month. I don't have any experience with bog filters (ego filters). The may a lot of sense and I'm attracted to the low maintenance and clear water. However, the best plans I've seen involve a PVC clean-out valve that is open to the air and a PVC water distribution under gravel, close to ground level.

I'm concerned that the PVC will freeze and crack during winter. I can think of a couple ways to prevent freezing PVC, but both would greatly increase maintenance. The PVC wouldn't be easy to remove during winter. Draining the water would keep the PVC from freezing, but then the plans in the bog are likely to die because their roots are exposed to the cold freezing air.

I live in Ohio, where winter temperatures are regularly below freezing and at times go below 0 Fahrenheit.

If you live in a cold climate and have succeeded at having a bog for at least one winter, please share how you were successful. Did you use PVC under the gravel to distribute water? Did it freeze? What about a clean-out value? How often have you had to replace cracked PVC?

Thank you.

 

[Mmathis]

Hello and welcome! We do have many members here from colder climates, so I’m sure they’ll be along shortly.

But I have a couple of questions: when you say “small pond,” what size are you talking about, and will it be in-ground or above-ground?

 

[j.w]

@BeginnerMind
Too mild here to help w/your question.

 

[addy1]

Welcome to our forum!

My bog has lines under the gravel, 2 feet down. The bog stays full of water over winter, the lines feeding the bog retain some water in winter (external pump) I do remove the pump over winter.
I have not had any lines break.

 

[mrsclem]

As long as the remaining water in the pvc has room to expand when it freezes you are ok. You want to leave the water in the bog for the plants. Just make sure you leave the ends of the pvc open. I have caps on my cleanouts but leave them on during winter. I pull the pump and supply line going to the bog.

 

[poconojoe]

I'm across to the east of you in Pennsylvania, zone 6b.
I leave my bog running 24/7/365.
My pump is the submersible type.
I was a little nervous the first winter. I was afraid the water from the bog would flow on top of the frozen pond and escape the system.
Well, no problem. The water from the bog kept an opening in the pond ice. As insurance, I had a pond deicer nearby just in case. But there was absolutely no reason for concern in my case.

None of my pipes have cracked from freezing.
As long as there's room for expansion or you keep the water flowing, you should not have a problem.

My bog has two 2" pvc pipes laying in the bottom, each 10 feet long. They are buried with 12" of gravel. Each has a vertical clean-out stack with screw caps for access.

 

[BeginnerMind]

Welcome to our forum!

My bog has lines under the gravel, 2 feet down. The bog stays full of water over winter, the lines feeding the bog retain some water in winter (external pump) I do remove the pump over winter.
I have not had any lines break.

Thank you for the response. I've read that the bog should be higher than the pond, so I hadn't though to have it 2 feet deep. Since that is what you did, and it works for you, I'll consider how I would build that. I wonder, does the line from the pump to the bog go up and over the edge of the pond, or did you cut a whole in the pond liner or have one line for pond and bog, and just separate then with a wall? Any suggestions on where to view plans for a build like yours would be great appreciated. Thank you!

 

[poconojoe]

I wonder, does the line from the pump to the bog go up and over the edge of the pond, or did you cut a whole in the pond liner or have one line for pond and bog, and just separate then with a wall? Any suggestions on where to view plans for a build like yours would be great appreciated. Thank you!

I didn't want to make any holes in my liner.
That was just a scary thought for me.

I ran mine over the wall and covered most of it with rocks. You can see about 6" of it. It's black flex PVC and not very noticeable.

None of my plumbing is outside of the pond/bog. If there's ever a leak, no water can escape the system.

 

[poconojoe]

Any suggestions on where to view plans for a build like yours would be great appreciated. Thank you!

I'll give you the link to my build first since it's shorter.
https://www.gardenpondforum.com/threads/my-add-on-bog-build.26848/


Then @addy1 has an extensive and very informative showcase with tons of info, including input from lots of people.
https://www.gardenpondforum.com/thr...upflow-filter-eco-filter-wetland-filter.6894/

There's a lot of info there.

Any questions, just ask

Hope this helps.

 

[addy1]

Thank you for the response. I've read that the bog should be higher than the pond, so I hadn't though to have it 2 feet deep. Since that is what you did, and it works for you, I'll consider how I would build that. I wonder, does the line from the pump to the bog go up and over the edge of the pond, or did you cut a whole in the pond liner or have one line for pond and bog, and just separate then with a wall? Any suggestions on where to view plans for a build like yours would be great appreciated. Thank you!

I put a two inch pvc "drain" at the bottom edge, plumbed to come out with a ball valve. "drained" it once, for a bit, nothing but clean water came out, never did it again. The input lines all go up and over the bog edge. With a external pump all is outside of the pond where the pump is. I have not hidden things as well as others, but also it is not real noticeable. I have 1/2 55 gallon barrels over the pumps, the stream pump and the main pump. Was going to build a neat shed, notice the was.

The lines are exposed in winter, with the pump removed I pull part of the connection so all lines are open to the air, never had one crack yet.

I have a wall between the pond and bog, built with landscape timbers. One piece of liner for both.

 

[BeginnerMind]

Welcome to our forum!

My bog has lines under the gravel, 2 feet down. The bog stays full of water over winter, the lines feeding the bog retain some water in winter (external pump) I do remove the pump over winter.
I have not had any lines break.

Thank you, addy1! That is very helpful. I had read that the bog should be at a higher level. But if it is 2 feet deep, I'd be more comfortable. Thanks for sharing you experience.

 

[BeginnerMind]

I'm across to the east of you in Pennsylvania, zone 6b.
I leave my bog running 24/7/365.
My pump is the submersible type.
I was a little nervous the first winter. I was afraid the water from the bog would flow on top of the frozen pond and escape the system.
Well, no problem. The water from the bog kept an opening in the pond ice. As insurance, I had a pond deicer nearby just in case. But there was absolutely no reason for concern in my case.

None of my pipes have cracked from freezing.
As long as there's room for expansion or you keep the water flowing, you should not have a problem.

My bog has two 2" pvc pipes laying in the bottom, each 10 feet long. They are buried with 12" of gravel. Each has a vertical clean-out stack with screw caps for access.

Thanks poconojoe! Your set-up sounds ideal. Thank you for sharing your experience. Do you by chance have plans or a design you could share, or did you create it as you went? Your response is the 2nd one mentioning room for expansion. What does that mean in relation to the bog? What I've seen is that most bog pipes on the bottom have periodic holes drilled in them. Is that the opportunity for water to expand outside the pipe via the holes?

 

[BeginnerMind]

I'll give you the link to my build first since it's shorter.
https://www.gardenpondforum.com/threads/my-add-on-bog-build.26848/


Then @addy1 has an extensive and very informative showcase with tons of info, including input from lots of people.
https://www.gardenpondforum.com/thr...upflow-filter-eco-filter-wetland-filter.6894/

There's a lot of info there.

Any questions, just ask

Hope this helps.

Thanks. I was replying one by one. Just seeing this post with the link, and I'm going to check it out. Thanks for sharing!

 

[GBBUDD]

As long as the remaining water in the pvc has room to expand when it freezes you are ok

agreed this helps in a big way. The type of piping used helps as well. such as FLEX pvc over hard pipe and not to even be considered is kink free tubing

I have caps on my cleanouts but leave them on during winter

If i have ANY points where the plumbing is exposed and i know there's water above the freeze line for the area it gets opened. that way like was said the water when it freezes has a place to expand without blowing the pipe apart.

 

[poconojoe]

Thanks poconojoe! Your set-up sounds ideal. Thank you for sharing your experience. Do you by chance have plans or a design you could share, or did you create it as you went? Your response is the 2nd one mentioning room for expansion. What does that mean in relation to the bog? What I've seen is that most bog pipes on the bottom have periodic holes drilled in them. Is that the opportunity for water to expand outside the pipe via the holes?

As for plans, ideas, pictures, extensive discussions....Did you look at the links I posted back in post #9?
Plenty of info there.

Expansion:
The bog walls should be a bit higher than the water level in the bog, just in case there's any upward expansion or wicking of water off of plants.

A lot of us prefer cutting slits in the pipes instead of drilling holes. I think there's a less change of gravel blocking slits than holes.
Their purpose is to distribute the pond water throughout the bog.