Simple (Too simple?) biochamber set up

[Chub_by]

Hey everone, hope you're all holding up well!

Been thinking of switching up some things in my pond and one thing I want to change is the filtration setup. Until now I've been using a cartridge filter where coarse and fine sponges double up as both the mechanical and biological media. It's somewhat efficient for ponds with lower stocks but since I'm planning on switching mine up and introducing some predators I reckon a specific bio chamber is in need. Also have a lot of bio media lying around so why not give some DIY a shot.

For space and practicality reasons, I've been thinking of using a duplicate filter box (i.e the same one the cartridges are in) and fitting in a divider as is used in a sump, then running the water in from the original filter, down through some media, up through some media on the other side of the divider and out through the same diameter PVC pipe the original filter uses. Here's a (very crude) drawing of how I'm imagining this; I will probably fit a filter sock over the first PVC pipe from the original filter but I'm not looking to drill any bulkheads or the likes so I'm planning on letting the water just run in like it would in a trickle filter.



Some questions:

1. Would I need something to distribute the water coming from PVC Pipe #1 into the second filter box? i.e like a drip tray or something so that the media is entirely covered.
2. Will it work if the PVC pipe has the exact same diameter? I'm not too worried about the second box overflowing (the flow from the pump isn't enough to completely "fill" the diameter of the first pipe) but I wonder if I'm overlooking something.
3. How do I calculate how much space I need to leave under the divider according to the pump's flow?

I'm also curious about how much I need to elevate box #1 above box nr 2. Obviously it needs to be slightly higher for the water from the Pipe to hit the second box but other than that it's irrelevant, correct?

If anyone has any remarks or questions about the setup, please do let me know. Been in the hobby for a long time now but pretty new to the DIY side of things so I'm aware my explanations probably make little sense.

 

[Chub_by]

Bump

 

[Gpdriftwood]

Your diagram looks good. Same size pvc should be fine. Sump baffle should only need to be up an inch or 2.

 

[fishdance]

With down flow like your diagram it will pond up very easily and frequently under light loads.

Have you considered upflow with a purge drain at the bottom of each chamber? So similar to second chamber but for both.

This lets you go much longer between maintenance as the water seeks the easiest path (uniform clogging) resulting in higher back pressure even though it's an open gravity fed system.

The other big advantage is at cleaning you turn pump off (or bypass water to next chamber if you don't want to ever stop flow) and shake all the media into the chamber. Let all the dirty muck settle then open the bottom drain to gravity flush out. If you have heavy media you can use nylon bags or air manifold to stir. A leaf blower or reversed wet/dry vacume will provide enough air.

 

[Chub_by]

Your diagram looks good. Same size pvc should be fine. Sump baffle should only need to be up an inch or 2.

Thanks! I assume lowering the baffle would improve flow through the biomedia but raise the water level faster once the first level clogs, correct?

 

[Chub_by]

With down flow like your diagram it will pond up very easily and frequently under light loads.

Have you considered upflow with a purge drain at the bottom of each chamber? So similar to second chamber but for both.

This lets you go much longer between maintenance as the water seeks the easiest path (uniform clogging) resulting in higher back pressure even though it's an open gravity fed system.

The other big advantage is at cleaning you turn pump off (or bypass water to next chamber if you don't want to ever stop flow) and shake all the media into the chamber. Let all the dirty muck settle then open the bottom drain to gravity flush out. If you have heavy media you can use nylon bags or air manifold to stir. A leaf blower or reversed wet/dry vacume will provide enough air.

Thanks for the in-depth reply. The water is mechanically clean once leaving the first filter (which is, after all, predominantly mechanical filtration) so if I use filter mats and floss before the first block of biomedia I should be alright, no?

As for upflow; do you mean water entering the second chamber from the bottom, going over the baffle and draining out of the bottom in the end? Wouldn't really be possible since the filter boxes are designed with an outflow at the top so it necessarily has to go out on top. The upside to this, though, is that the boxes are also designed with a drain on the bottom left so cleaning should be as easy as you described it

 

[Gpdriftwood]

Thanks! I assume lowering the baffle would improve flow through the biomedia but raise the water level faster once the first level clogs, correct?

Correct. How wide is the sump? As in how wide is the space under the baffle? Having only (1) 2" outlet, as long as your sump chamber is at least 16" wide @ 1" high I don't think u would have an issue personally. What is the flow rate coming from the first box?

 

[Chub_by]

Correct. How wide is the sump? As in how wide is the space under the baffle? Having only (1) 2" outlet, as long as your sump chamber is at least 16" wide @ 1" high I don't think u would have an issue personally. What is the flow rate coming from the first box?

The sump is 38cm wide (just over 15") and the pump does 8000lph (~2065 gph).

 

[Chub_by]

Also I reckon to prevent clogging of the bio chamber I could probably use a large filter sock over the pvc pipe coming out of the mechanical chamber

 

[Gpdriftwood]

The sump is 38cm wide (just over 15") and the pump does 8000lph (~2065 gph).

The sock is a good idea. Might want the baffle 1.5"-2" high with that much flow.