above ground bog filter

[trev]

hi guys i kneed a bit of help with my bog filter it is 8ft long 14" wide x 14" deep. i'm using 7ft x 1"1/2 pvc pipe i have put 1/4" holes app 6-8" apart that gives me 12 holes is this enough as i read somewhere they should be 3" apart. also i ordered enough 3/8" pee shingle to fill the box to 1ft deep, unfortunately was out when it was delivered and my son's moved it into the garden, the builders had delivered mixed gravel can i use this if i separate it into three sizes i.e a layer of 4" deep x 3/4" on the bottom then a layer 4" deep x 3/8" in the middle topped of with a layer 4" deep 1/4" on the top for potting plants in. i'm hoping this will work as i don't fancy paying out another £45 on more gravel plus moving it a100 yds to my garden thanks guys

 

[hdavid44]

I am no expert on bogs but I put one in in desperation when I could not clear the algae. MY bog has no shingle or gravel at all. Just water in and water out. But I do have several nbags of lava rock to provide bacterial surfaces and I have several sponges to do the same.

The bog has had limited success in controlling algae and I have since reverted to using a UV light part time which is doing the trick. I also cut back on feeding my koi.

Several posters here have suggested various plants to take up the nutrients -- hornwort, parrots feathers, water hyacinth, etc. I suppose you can try all of the above but if you have an algae problem and all else fails insert a UV light in the path from the pond to the bog...

Harry

 

[Waterbug]

I don't think the pipe systems under bogs are a great idea. Then benefit to bogs imo is the length of time water spends in the bog. Pump water in one end and it flows out the other. Add a pipe beneath and water can travel down the pipe, bypassing much of the bog.

I wouldn't worry about the mixed gravel, it's all good.

 

[don't ask]

i would agree that the size wouldn't matter too much as long as your holes are not larger than the stones..then i would follow your plan..
and welcome to the forum

Waterbug so without the pvc would you need to angle or slope the bog from one end to the other to achieve the desired results?

 

[taherrmann4]

I just put in an above ground bog a few months ago and I made slits about 1/3 of the way through the 2" pipe with my miter saw every 6". The holes are facing down, then it is filled with 5/8 gravel. I don't think you have enough holes in the pipe to get enough flow.

 

[hdavid44]

I don't think sloping the bog will have any effect. The water will find its own level.
You may wish to insert a bottom drain to more easily remove sludge. Or get a vacuum to do so periodically.

 

[taherrmann4]

Here is a thread on bog building.

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

 

[addy1]

hi guys i kneed a bit of help with my bog filter it is 8ft long 14" wide x 14" deep. i'm using 7ft x 1"1/2 pvc pipe i have put 1/4" holes app 6-8" apart that gives me 12 holes is this enough as i read somewhere they should be 3" apart. also i ordered enough 3/8" pee shingle to fill the box to 1ft deep, unfortunately was out when it was delivered and my son's moved it into the garden, the builders had delivered mixed gravel can i use this if i separate it into three sizes i.e a layer of 4" deep x 3/4" on the bottom then a layer 4" deep x 3/8" in the middle topped of with a layer 4" deep 1/4" on the top for potting plants in. i'm hoping this will work as i don't fancy paying out another £45 on more gravel plus moving it a100 yds to my garden thanks guys

Welcome to our group!

My bog is large, it controls all algae in my pond, full of pea gravel and plants. I do have some algae in the bog with this heat hitting, the slimy stuff, it comes and goes. The pond is currently algae free, has been all summer. .

I would suggest you make slits in your piping, the holes can get plugged with the gravel. We made 1/4 inch slits using a circular saw about 1/3 of the way through the pipe. I have my slots facing down, with a layer of liner between the piping and the liner.

We put the slots in about every 6-12 inches, (27 feet long) Two pipes in a bog around 4.5 feet wide.

I would start with the bigger gravel work up to the smallest on the top or mix it, probably will make no difference.

The bogs I have made, where the water flowed over the top of the gravel, the gravel just got covered with muck. I prefer the piping under the bog.

 

[ComputerGuy]

I'm with Addy on this one. The piping under the bog is a much better way to go. Make sure you put a clean out on the opposite side of where your water comes in though. Then if you have any kind of stoppage or anything, you can run a snake from either the input or the clean out end. Flowing water into one side of a bog and out the other would tend to create "rivers" for the water to travel through the bog without maximizing the contact with the gravel. When you pump in from the bottom, gravity helps you maximize your contact with the gravel and plant roots and gives you more contact time.

 

[j.w]

trev

 

[trev]

thanks to all of you for your help i'm going to double up on the holes in my feed pipe just in case i can always reduce the flow to suet i already have a drain in the bottom and i'm going with the three layers of gravel (easier on the back) once i have it all up and running i will post some pics so you can see what your help has helped me achieve. thank you all once again.

 

[addy1]

Have fun, I never drain mine, so far, but it never hurts to have a drain for a good back flush if you need it.

 

[brandonsdad02]

A bog with no piping on the bottom and gravel is just a shallow pond. I just added a bog to my pond about a month ago and its been working great. Everything slopes away from my pond so the bottom of my bog isn't level at all. It gets shallower the closer it gets to the pond. I have 1 1/2" pvc pipe in the bottom of mine with slits cut about 1/3 thru the pipe with the slits facing down. Mine is full of 3/8 pea gravel. You can try to wash it first but most realize that there is just too much gravel to wash and just dump it in dirty. I have about 3/4" of water on top of my gravel. I probably should have added more gravel but after putting in 45 bags of 3/8 pea gravel at 60lbs a bag, I was wore out. The gravel helps with filtering along with lots of plants.