Explanation of 'BOG' please

[nancyp]

Hi - I've got my pond up and running very nicely this year. I'm in the process of adding plants now. I was just curious - what is meant by a bog? And how does it help your pond? I see the pics of the liner with pvc, and pea gravel, but what does it actually do? Is it shallow, and only for plants, or is it for some fish too? Are the plants in pots in there or in the gravel? How does it get cleaned out? Thanks for the info!

 

[Bev12]

Like your pond! Sorry I cant help with the bog

 

[Shard MacD]

Hi Nancy,
Your pond looks great. I hope some one helps you with these "bog" questions, I too would like to know more about it. Intrigued to say the least. If I find out any thing I will share...

 

[Mmathis]

I'll give this a try, but hopefully you'll get some better answers, LOL This is a very simplified answer.

In nature, a "bog" is a wetland area. In ponding, a "bog" is usually an area that is part of but separated from the pond. It's used as a FILTRATION system -- the roots of "bog" plants take in the nutrient rich water.

Water from the pond is pumped into the bog. In comparison, if you didn't use a bog, the water would be pumped through some sort of filter. The bogs are usually about 18" deep and have the system of PVC pipe along the bottom. The PVC pipe has either slits or holes drilled in them for the water to flow out. Then, pea gravel is added followed by plants. Pond water is pumped through the PVC pipe, where it then flows UP through the pea gravel where the plants' roots have access to it. The roots do their job, and clean water goes back into the pond -- Bogs are designed where the water from the bog will gravity-flow back into the pond.

So, to answer specific questions: a bog is used as a filter; is usually 12" - 18" deep; for plants, as there isn't sufficient water depth for fish; plants go in bare root [but when planting, they say to plant with the dirt ball intact, as the plants need this until they get started growing]; you add a "clean-out" pipe to flush it as needed.

Mine is under construction, so I'm learning as I go. Those who have bogs LOVE them. Water quality is great and they claim no algae [suspended] problems. Plus, the added benefit of beautiful plants. And if the plants get out of control, it's easy to pull them from the gravel.

Addy has an EXCELLENT thread under the POND CONSTRUCTION & EQUIPMENT section. She shows several different ways to construct a bog, as well as lists of plants that are bog-friendly.

https://www.gardenpondforum.com/topic/6894-bog-building/

Keep in mind that, as with anything, there is no RIGHT or WRONG [well......] way, just DIFFERENT ways. And lately there's been some controversy regarding bogs. You just have to do your research.

I hope this helps!

 

[Fishylove]

:clapping: Very well done TM! And you were worried

 

[Mmathis]

:clapping: Very well done TM! And you were worried

Thanks!

Well, I have to be careful to LEAVE OUT the technical stuff -- you know, the kinda stuff that WATERBUG is good at providing, like they "why's" and "how's."

 

[crsublette]

Yep, Mmathis pretty much got it covered quite well.

Also, check out the thread, this is why I'm not a fan of "bogs". HOWEVER, even knowing this, personally, I would still consider doing a bog as long as particular requirements are satisified. Requirements such as: 1) pre-filter the water before entering the bog; 2) do not heavily feed the fish; 3) do not heavily overstock the pond with fish; 4) using many many well matured plants and willing to do the proper plant maintenance.

In our context, a "bog" is essentially a decent "cheap" all-in-one filter. "Cheap" in that, even though the initial diging and material can add up, a properly installed bog will last for 20 years or more; so, in the long run, they work out as long as the above requirements are met. The "bog" essentially serves as mechanical filter and a biological filter. A mechanical filter cleans the water by removing the solid particulates out of the water to give the water that "crystal" clean appearance. A biological filter cleans the water by removing the chemicals out of the water to make the water healthy.

The mechanical filter portion of the bog is only as good as you build it. In particular, the bog's mechanical filter should filter out the finer solids rather than the larger solids and this is why a pre-filter is used. A pre-filter catches the big stuff such as leaves or twigs before it gets pushed into the bog. The reason for the prefilter is that the big debris will eventually clog up the bog faster so filter this stuff out before it enters the bog.

The biological filter portion of the bog is where the fish toxic chemicals converts into a plant fertilizer. Anywhere there is surface area will encourage bacteria to convert these chemicals to plant fertilizer and these bacteria are naturally occuring all around you. The plants in the bog will then remove the fertilizer portion out of the water. The more plants you have in there then the more is removed from the water.

I believe a bog works fine as long as the requirements are met. Also, bogs take time to "mature" so to grow the proper bacteria in it and for plants to grow as well. So, first year might be a little rough, but the second year the bog should really work well.

 

[addy1]

For my system

>>> the input of the water comes from just above the bottom of the pond.
>>>I have a huge leaf basket before the external pump to catch any large matter, a sort of prefilter
>>>A ton of plants / 2800 lbs of pea gravel (I wanted a lot of plants) and dug a deeper and bigger hole than I thought and did now want to refill it.

The first no fish pond summer, the water was murky, (we only had a 125 gph pump running to just circulate the water) I was still working on the system. I did not clean our pea gravel, used a slow flow pump and a pretend skippy filter to clean out the pea gravel dust, dirt. The few fish I added died due to acidic water. Did not even have green water that summer.

The second summer, pump running, fish invited to live, frogs moved in and all sorts of pond critters. The pond has never been cloudy, green or had string algae. There is a touch of carpet algae, not even much of that.

I have back flushed the bog a few times when moving pipes around, nothing but clean water comes out. This is the 4th summer.

We have 200 plus fish, multiple other critters, I feed lightly, some times heavy.

This is my third and biggest "bog" filter, just love it. I would not use any other method to filter the pond. The water stays perfect (quit testing except for ph off and on), the fish happy, me happy............lol
If it lasts 20 plus years I will be more than happy.