Bog filter types and sizes

[MitchW]

Hi Everyone,
I am building my first Koi pond...I know it is not an easy task. I always wanted one, and I figured it is a good time to do it.
I am located in Toronto, so we have to consider the cold weather, the raccoons, the minks and the blue herons.

I have pretty well read most of the info posted by @addy1, @poconojoe, @GBBUDD, @Lisak1 and others.
For me, no doubt that I want to go with a bog filter. The question is which method? I know that @addy1 has done the 12" pea gravel method and @GBBUDD went with the snorkel and centipede, and 3 sizes of rocks method.

The size of the pond will be about 12000 gallons..."I got a bit backhoe-happy" when I was digging the pond.

I just saw this YouTube video by Nelson Water Gardens. She keeps referring to 12" of pea gravel and not more.

Would love to hear your opinions on this. Thanks in advance.

 

[Jhn]

Pond that big with koi...... I would go with the snorkel and centipede, aquablox style bog, it is a better design than the straight pea gravel bog. They both work, but the snorkel will give you the ability to pump out any silty buildup in the bog if necessary. It is designed to let the silt settle out of the water and collect in the lowest point of the bog(the snorkel). This allows the bog to work more effectively ie no channeling, which can occur in a pea gravel bog, especially if there is no prefilter of some sort before the water gets to the bog.

I just rebuilt my bog on the 10000gallon pond this past spring from a 10 year old 12-18” deep pea gravel bog to a 3’ deep snorkel and centipede style. I mainly did this because I put a net up high over the pond to keep herons and hawks out and the original bog was a tad undersized so I needed a larger more effective bog as I no longer have nature’s population control on my fish.

Here is a link to the thread https://www.gardenpondforum.com/threads/redesign-of-bog-wetland-filter.26516/

As for only going 12” deep with a pea gravel bog, that is more of a minimum. Issue with a 12” deep bog is you would have to watch which plants you put in there you don’t want ones with aggressive roots getting down to the pipes and clogging the slots up. Addy1’s bog is 2.5’ deep and works fine.

 

[Mmathis]

There is a thread already active on the forum. Maybe you can get some information From this.

2 Types of DIY Bog filters - 12 inches of pea gravel or 3 foot of large medium small rocks?

The more I research building a wetland/bog filters the more confused I get. I'm looking to turn a pool into a pond, it will be about 3000 gallons and the area I have set aside for the bog is approx. 36 inches deep and 20-30% of the area of the pond. I'd like to have the option to take a dip in...

www.gardenpondforum.com

 

[GBBUDD]

you don’t want ones with aggressive roots getting down to the pipes and clogging the slots up.

I agree fully that a 12" bog on a larger pond is large risk. almost every plant can have it's roots reach down a foot "almost" But some like the papyrus completely filled a 18" aquablock in one short season to the point it looked like a man made sponge . But put those roots into your supply pipe to the bog and you will undoubtedly will restrict water flow reducing the amount of output and increasing the energy demand to push that water. Not in a small set up 800 to say 3000 gallon pond the consumption can be minimal but step up to 10,000 gph and only getting 8000 from increased head pressure and that will add up quick

 

[MitchW]

Pond that big with koi...... I would go with the snorkel and centipede, aquablox style bog, it is a better design than the straight pea gravel bog. They both work, but the snorkel will give you the ability to pump out any silty buildup in the bog if necessary. It is designed to let the silt settle out of the water and collect in the lowest point of the bog(the snorkel). This allows the bog to work more effectively ie no channeling, which can occur in a pea gravel bog, especially if there is no prefilter of some sort before the water gets to the bog.

I just rebuilt my bog on the 10000gallon pond this past spring from a 10 year old 12-18” deep pea gravel bog to a 3’ deep snorkel and centipede style. I mainly did this because I put a net up high over the pond to keep herons and hawks out and the original bog was a tad undersized so I needed a larger more effective bog as I no longer have nature’s population control on my fish.

Here is a link to the thread https://www.gardenpondforum.com/threads/redesign-of-bog-wetland-filter.26516/

As for only going 12” deep with a pea gravel bog, that is more of a minimum. Issue with a 12” deep bog is you would have to watch which plants you put in there you don’t want ones with aggressive roots getting down to the pipes and clogging the slots up. Addy1’s bog is 2.5’ deep and works fine.

Thanks @Jhn I did see your thread. I was trying to figure out if the 12" pea gravel method would work for a larger pond. Our property sits on hard clay, and I was trying to dig. What I plan to do now is to dig may be a foot and build up the rest. Not sure if I want to build the frame of the bog with concrete blocks or armour stone. Thanks again.
[/QUOTE]

 

[MitchW]

There is a thread already active on the forum. Maybe you can get some information From this.

2 Types of DIY Bog filters - 12 inches of pea gravel or 3 foot of large medium small rocks?

The more I research building a wetland/bog filters the more confused I get. I'm looking to turn a pool into a pond, it will be about 3000 gallons and the area I have set aside for the bog is approx. 36 inches deep and 20-30% of the area of the pond. I'd like to have the option to take a dip in...

www.gardenpondforum.com

Thanks @Mmathis . I didn't see that one before.

 

[addy1]

I know that @addy1 has done the 12" pea gravel method

I did the pea gravel method, but my pea gravel is about 2.5 feet deep , 27 feet long, 4.5 feet wide. I don't have koi but could, have plenty of gold fish and my bog takes very good care of my pond. About 12000 gallons if you add up the ponds I have being filtered by the bog.

 

[Lisak1]

I think the shallower bog could work IF it was large, like @addy1 . That 30% of the surface area of the pond is an important figure to shoot for - and bigger is only better.

I think I said it on the other thread, but I'll mention it again - if you're doing STRICTLY pea gravel, then the shallower method makes sense. If you do Aquablox and centipede, etc., you still end up with that same gravel layer on the top. The void area provided by the Aquablox creates space for sediment to settle, which may be more important depending on the size of fish, where you draw water from, how much debris gets in the pond, etc.

 

[cas]

Our property sits on hard clay

One thing that helped me when digging in clay - I would fill the hole with water and let the clay soften. It was easier to dig, but boy did the clay get heavy!

 

[MitchW]

One thing that helped me when digging in clay - I would fill the hole with water and let the clay soften. It was easier to dig, but boy did the clay get heavy!

Yes, it does...the clay just sticks and adds a couple of pounds to the weight of the boots...LOL. Not to mention, slips like heck. LOL

 

[addy1]

Our land was a bit of dirt with layered shale. The only reason we have ponds was my hubby buying me a kubota tractor with a backhoe and bucket. We could barely dig a hole for a bush.

 

[MitchW]

I did the pea gravel method, but my pea gravel is about 2.5 feet deep , 27 feet long, 4.5 feet wide. I don't have koi but could, have plenty of gold fish and my bog takes very good care of my pond. About 12000 gallons if you add up the ponds I have being filtered by the bog.

Thanks @addy1 Wow, that's impressive. How often do you clean it up, and what do you do to clean it up?

 

[addy1]

How often do you clean it up, and what do you do to clean it up?

The gravel, never, the plants off and on during the summer yank excessive growth. Fall, chop down dead plants, spring rake out any excessive plants and leaves. Turn it on and ignore. We did not wash the gravel, yeah the water was pure murk and now nothing but clear water. I did the quilt batting for a bit then said forget it I am not that obsessive about clear water. Well now I always have clear water, never green in the spring, never a huge, if at all, string algae bloom.

Love my bog!

 

[MitchW]

The gravel, never, the plants off and on during the summer yank excessive growth. Fall, chop down dead plants, spring rake out any excessive plants and leaves. Turn it on and ignore. We did not wash the gravel, yeah the water was pure murk and now nothing but clear water. I did the quilt batting for a bit then said forget it I am not that obsessive about clear water. Well now I always have clear water, never green in the spring, never a huge, if at all, string algae bloom.

Love my bog!

Very helpful to know. Really speaking and in terms of plants, this is regular maintenance when you have a garden, right? Thanks again.

 

[addy1]

this is regular maintenance when you have a garden,

Well not here, I ignore our land gardens, all most all are wild flowers whatever grows grows.