To bog or not to bog.

[Meyer Jordan]

What about biological filtration? If your "filter" is removing things from the water that the naked eye can't see is it still subject to clogging?

There can be quite a bit of TSS (Total Suspended Solids) present in a column of water whose particle size is smaller than the human eye can detect, but yet these particles are not truly dissolved. These are broken down mainly by fungal action and not bacteria as is commonly thought. All of these particles carry an electrical charge (positive or negative) and depending on the electrical charge of the surface of the substrate will adhere. Over time this can build to a considerable mass.

Of course, as with many other things connected with a pond, if one can control the source of the problem then the problem is moderated. Proper mechanical filtration before the 'bog' will greatly reduce this TSS, allowing the 'bog' to continue for some time without any flow issues. Providing a means of 'settling', either through a tank/chamber or through settling pools (such as what @addy1 has incorporated into her stream, will remove most of the these fine suspended particles.

 

[Gordo33]

The larger the 'bog' in relation to the fish load.and general size of the pond the longer it will take for this 'channeling' to become problematic.There is a positive side to this as the areas that are clogged will become anaerobic and contribute to the denitrification process

several questions:
1. For smaller sixed bogs , 2x5x1.5 ft, how do you know the channeling has become problematic?
2. If channelig has a positive side effect would back washing the bog eliminate the anaerobic build up negating the positive side effect?
3. If question 2 is yes then would a partial back flush allow some channeling to still exist and maintain the positive side effects?

 

[Meyer Jordan]

several questions:
1. For smaller sixed bogs , 2x5x1.5 ft, how do you know the channeling has become problematic?
2. If channelig has a positive side effect would back washing the bog eliminate the anaerobic build up negating the positive side effect?
3. If question 2 is yes then would a partial back flush allow some channeling to still exist and maintain the positive side effects?

Channeling in any size 'bog' is evident when greater water movement is noticed in one or more areas of the 'bog'. Severely clogged systems will exhibit almost a bubbling effect in these areas.
Don't get the wrong impression, it is better to not have a clogged 'bog'. You do not really want channeling in an upflow system.. The only reason that I mentioned denitrification is that until the 'bog' can be effectively backflushed some benefit is being realized as result of the clogging (channeling), but it in no way replaces the benefits derived from a free-flowing system. The plants are in place to remove the Nitrate.

 

[qclabrat]

starting to think more about the bog filter which is next, should I use all pea gravel or bigger rock as the bottom and perhaps separating the larger rocks from the pea gravel with a few layers of plastic mesh

my thoughts are that the larger rocks could help with the water flow but I could be completely wrong
I'd like to avoid using lava rock so rocks would be 2-3 inch pieces of shale I've collected from the big dig

 

[Faebinder]

starting to think more about the bog filter which is next, should I use all pea gravel or bigger rock as the bottom and perhaps separating the larger rocks from the pea gravel with a few layers of plastic mesh

my thoughts are that the larger rocks could help with the water flow but I could be completely wrong
I'd like to avoid using lava rock so rocks would be 2-3 inch pieces of shale I've collected from the big dig

Pea gravel. Plants will want to grow their roots down and pea gravel is easier for them to go down through all the way to the liner.

 

[Meyer Jordan]

Pea gravel. Plants will want to grow their roots down and pea gravel is easier for them to go down through all the way to the liner.

I disagree. Aquatic plants need only enough substrate in which to anchor their rootball and support the upper growth that is not submerged i.e. Iris can be grown when only attached to a brick or other object.
The amount (and type) of substrate, in this case pea gravel, will affect the total surface area available for colonization of nitrifying bacteria.
Depending on the total organic load of a pond, however, because of the small void space between the individual rocks, the sole use of pea gravel may not be the best choice.

 

[addy1]

2-3 inch pieces of shale I've collected from the big dig

I dug up a lot of shale, after a year out of the ground, or in the water it all turned to mush.