Let me offer you a much better design that will provide better bio and better mechical and be very easy to deal with.
You'd figure after 30 years, I know what is practical and works and has built in redundancy
I'll make a drawing and post it.
In this drawing, the tower is a simple tube or box shape with a bulk here fitting at the top.
So the top is sealed, but removal able. You add a rubber seal, much like those weather seals they use on doorways etc and on car doors etc.
So it just slips on or off but is sealed from allowing gas in/out.
The yellow is a large piece of open cell 30 pore/inch that's large reactangle shape etc. This will stay very clean over all and require a good qeeze maybe once every 2-4 months.
The sock looking thing is the key to this design.
That's a cheap bag filter. They use micron rated filter pads, sop 100, 50, 20, 5 and 1 micron ratings maybe used.
Some add a sock in a sock. So add a 100mic inside and then and 5 micron on the outside of that to prevent rapid clogging.
The dotted line is just some egg crate that allow the ring on the bag filter to remain stable and supported. You can glue some small piece of plastic to support the egg crate there.
Now if you are really into things, this design allows you several neat options.
The air gap inside the tower with the bag?
You can add some air line to the and drill a hole and connect that air gap back into the return pump's suction side.
This will produce a mist effect and will be a mix of both degassed CO2 and air that was sucked into the over flow. Note: the air may displace some, but not all the
CO2 in solution. How much would tough to figure out I'd think.
Still, some recycling would occur of the deegassed CO2 also. Hard to say if they trade off would help.
Still, an interesting notion.
The other thing is to simply leave air/CO2 degassed gap alone and allow the filter to slowly dissolve it in the sealed tube/box. You do not want to make the chamber too gas tight, other wise it can fill up with gas and block flow, some slight leaking out is fine in other words.
Bag filters as they clog will simply over flow into the sump, so they are not an issue if you neglect things. I keep a pair handy so I can replace them fast. I just soak them in bleach for 1-2 hours and rinse and allow to dry till they are needed again.
The other optioin is to add a sealed bioball tower right before the bag filter. Basically you add one more chamber, and the water from that flows out into the bag filter via pipe, then the rest of the system is the same, the bag filter section does not need to be sealed in that case.
See other drawing for that. You can add the CO2 recirculation loop into several points also and fuse it with the venturi/reactor or add to the return pump suction side or feed into the CO2 reactor's pump's suction side as well.
A UV loop may be added prior to the CO2 reactor pump or in line with the return pump(better) and adding a heater etc is a good idea for most tanks
The other thing that can be added: a float switch to add replacement water for evaporation.
Plumbing the line to the tap water works well as there's not much Chorine/chloramines per day etc. But adding a carbon filter to the tap water, will remove that issue and allow you to do water changes by draining the tank slowly with a solenoid/timer for an automated water changer.
Regards,
Tom Barr
