Sticky Doc Bio Filter

[DrDave]

Hey doc how many rolls of poultry netting did you end up putting in each barrel?

Just one roll, cut in two so it was twice as long, half as wide. I laid them on top of each other and rolled them back up. It does not sit in the 55 gallon drum very concentric, but it does not have to for the aerobic bacteria to do it's job.

 

[ZmanArt007]

I know these skippy and doc filters have had a multitude of success stories... but they've never seemed to work for me... So I'm working on a new filter design, one that I can't find anything similar to online. It will more or less be an advanced version of a canister filter, but thats all I am going to say until the filter is completed. :salook:

 

[damian]

if i am going from the doc filter to a waterfall weir filter, what is the correct height relationship between the doc filter and the weir? currently, my doc filter is raised about 12" off the ground, so the top of it is about 48" high. i notice that a lot of the waterfall weirs have their inlet at the bottom, so i'm not sure of the proper placement of the weir so the inlet is in the best position to receive the flow from the doc filter.

 

[DrDave]

It doesn't matter how high as long as you have enough pump to move the water to that height and still get the flow rate through the filter. Look at you pumps data sheet on head and see what the GPH is at that height.

 

[damian]

Yeah the pump can handle it. I was just concerned that water could overflow the doc filter before it dumped out of the waterfall filter if the height was off

 

[DrDave]

If your pump is that powerfull, just add a ball valve and choke it down.

 

[damian]

i've included a competely awesome picture i drew to demonstrate my concern.

it seems like with the inlet at the bottom like this, the weight of the water in the weir as it fills would prevent additional water from being received. i.e. the water exiting the doc filter would be fighting against the pressure of the water in the weir and instead overflow the doc filter.

 

[damian]

in other words it seems like i am going to have to use a diy weir or find one with an inlet at the top so that the water from the doc filter just dumps into the top of the weir, or i'm a complete idiot and don't understand anything about fluid dynamics

 

[fishin4cars]

As long as the barrel and the water fall weir are the eaxact same level then the water will take the path of least resistance, There will be equal pressure so it's not really fighting against the pessure from one to the other,

 

[damian]

in the illustration above, wouldn't the path of least resistance be the rim of the doc filter?

 

[ComputerGuy]

The rim of the doc needs to be above (if just by a couple of inches) the weir outlet. That's how it looks in the picture.

 

[koidaddy]

Water is being pumped into the doc. Gravity is feeding the weir. Gravity goes down. As long as the waterfall is doing its job and the filter is level with or above it, it should be ok. Whats the flow out the waterfall weir?

 

[damian]

for some reason i don't think it's that simple, because gravity is also acting on all of the water in the weir above the inlet pipe.

 

[koidaddy]

Look at my two barrels that are joined. I raised the leading one(barrel 1) up a few inches because it was not enough out flow from barrel 2 and it wanted to overflow barrel 1. A larger opening on barrel 2 would also work. It also comes down to how much water is flowing.

 

[damian]

it seems to me that it would have to be something like (volume of water above the outlet hole in the doc filter + volume of water in the outlet pipe) > (volume of water in the weir above the inlet hole) in order for the water to dump from the weir