Backyard Aquaponics
A place to discuss aquaponics

I'm talking about a gravity flow (unpressurized) upflow filter using media like K1. It will be getting the flow direct from the fish tank so no way to use a pressurized pool filter.

Will have a purge valve in the bottom and an air supply I can turn on when I stop the flow in order to clean and dump the waste to the mineralization tank.

Here is a link with an example of what I'm thinking (except I don't have the nice cone bottom tank.)
http://www.koi-uk.co.uk/mechanical_filtration_capable_of.htm

Yep, that will work but I don't think you really need the Jap mat on the top (It might help but will work fine without and easier to clean). You can probably reduce the size as well. A 5 gallon bucket or smaller would probably do the trick - It's a trade off between water flushed and frequency of flush. I don't know how many fish he's made this for but his seems over built size wise for many AP systems (but very nicely done).

The water level will rise around the slotted column as the filter becomes plugged more with solids. This makes it easy to tell when the filter is getting blocked and needs flushing.

Well this is on a 1000 gallon fish tank so I want to make sure the filter could handle at least 20 gpm (so I don't think a 5 gallon bucket would do for me on this.) And the 15 gallon container I have handy I think is also a bit on the small side. Next size container that is easily available is the 32 gallon rubbermaid. Which while too small for a properly sized RFF I think it probably is about right for the upflow filter (other than not having the cone bottom)
Oh and I wasn't planning anything other than the bio-media, grates/screens on plumbing and the aeration device for cleaning.

"...clean it daily" ? arg

You might be surprised on the flow it can handle. You wouldn't want to shoot the water straight at the k1 though. Mine should have about 250 gph going through a 5 gallon bucket (I haven't done a bucket test), it's not struggling as far as I can tell (that's roughly 4 gpm through a 5 gallon bucket). The 32 gallon is definitely big enough and your 15 gallon may be big enough (your trying to put almost 17 gpm through).

The nexus eazy pod can put roughly 43 gpm through about 8 gallons of k1 media (30 L) (around 2600 gph) (That's 8 gallons of media the space it's in is larger). At that high of a volume it would probably work best as a prefilter - lower flows would give better results. From what I've read, it can handle up to a 1500 gallon pond on it's own or act as the prefilter on larger ponds. Anyway, I'm trying to show you how much leeway there is in the flow.

Boss,
You go commercial scale, you get to do some amount of cleaning daily no matter what.
I'm hoping that it is easier to clean that some of the other methods I've tried as stop gaps in the past.

(easiest things to install are simple filter bags or socks but during peak season they can need cleaning or change outs several times a day or more depending on the openings.)

I've also tried the parabolic sieve but since I didn't get wedge wire it tended to clog up with bio-slime too quickly and also needed very frequent cleaning or would wind up sending all the water from that outlet to the mineralization tank.

So now, I have all the flow from the tank (1000 gph plus a little) going to the bottom of a 32 gallon commercial rubbermaid trash can and flowing up through the bio-media before going out a slotted pipe in the top.

In the bottom of the can is a square of 1" pipe, slotted drain (slots facing down) that outside the can is a ball valve and a short bit of clear pipe before the pipe over to the mineralization tank.

Above the drain square is a square of pipe with small holes drilled facing up and this is for aeration just for the cleaning cycle.

At the top is a 4" slotted pipe to allow the water to flow out without letting the K1 type media escape.

Cleaning involves stopping water flow for a few minutes, letting a little water out of the upflow filter. Turning on the aeration to the upflow filter for a few minutes. Turning off the aeration to let the solids settle down. The letting the gunky water flow out of the bottom drain till it runs clear.

At least that is the theory.

At the moment I only have 1 cubic foot of the media in the filter but I have another cubic foot ready to go in should it seem appropriate. This only got turned on right before lunch today so we will see how it does. It was cold here last night so I don't really expect the fish too eat too much today (though I didn't feed them in the morning so they may be more eager to eat this evening) so it might be the end of the week before I can really start to form any opinions on the filter's functionality. (AND I will caution that you really need to give at least three weeks of operation before really deciding how new materials handle bio-slime before making any strong opinions about filtration function.)

Hum, I'd never heard of the nexus eazy pod, I'll have to look that up.

With the size plumbing I'm playing with, I'm glad I went with the 32 gallon can. The smaller tank would have just been too crowded. I know a 3" drain probably could be adequate but on the big systems I went with 4" for all the gravity flow drains. I'm running at least 18 gpm and possibly as much as 20 gpm depending on the number of towers also running on the system. I've not had issues with bio-filtration so it isn't like I'm expecting this to handle that, it is really just a solids filter since I would like to minimize the gunk getting through and if it works well, I'll implement something similar on the outflow from the mineralization system going back to the sump tank.
In that link I did on the basic upflow filter design they said 2000 gph so I know the 32 gallon can will easily handle my 1000-1200 gph.

Now I just need to sort out how to most efficiently mix/aerate the mineralization tank (which is just a 410 gallon tank 3/4 of the way sunk in the ground.) I will probably need a bunch of smaller airlifts. And then a settling chamber to keep most of the gunk from making it out the outflow to the upflow filter. Which on the mineralization system will be harder to clean since it will have to be mostly sunk in the ground and I won't be able to simply drain.

Ok, so the static media upflow filter has been online a few days. I have added the other cubic foot of media so now it has 2 cubic feet.

It does seem to trap an amazing amount of gunk down in the bottom (as I have seen when I open the drain tap and watch the clear bit of PVC going to the Mineralization tank.)

I have temporary aeration going in the mineralization tank. Right now just with air stones. I want to swap out for a bunch of airlifts for mixing but at the moment I don't have the size pipe I want to use for that on hand and haven't figured out what sort of layout would be best anyway.

I am planning an internal 5 gallon bucket upflow filter to go on the drain of the mineralization tank. My plan is that I will simply lift the bucket out to do the back washing. I just need to sort out a flexible hose to go from the clean drain of the bucket to the drain of the tank to allow me to simply lift the bucket up and perhaps use a hose to wash the media down a bit before lowering it back to it's hook to act as the mineralization tank polishing filter.

OK, finally, some pictures for you.

I simply placed the can inside the 100 gallon stock tank that is in place diverting water to the different places it goes from here. It was easiest to simply leave the stock tank in place and plumb through it for the waste drain.





Since the can is sitting in the tank where the water is going to, I really didn't need to install a pipe into the uniseal anyway, the yogurt container simply gives me something to shove the pipe with the slots onto to keep the media in the can.

Now I just have to decide if I'm gonna bother cutting a lid to fit around the inlet pipes or just keep using the foam with the weight on it.

Dirty water outlet with Valve and a clear PVC view pipe.

Need to protect the clear pipe from algae to keep it useful


Not sure if it is really visual enough in a picture but here is gunk flowing through the outlet pipe

And now the fun tank

Mineralization tank already has a bunch of gunk in it.

I've got some temp aeration with just air stones and the full output of one 9730 air pump going to four six inch air diffusers. (there is a 5th diffuser in there getting some air from the blower but it only sees air if I keep the diffuser hanging at only about half the depth.)

So my next issue was how to keep all that gunk in the mineralization tank as I move water through.
It is an in ground tank so not easy to put a can next to it as an upflow filter.

Hum, why not sink a bucket into the tank?
So 5 gallon bucket with a couple 3" holes in bottom to hold some net pots (keep the media in and allow for water to flow up and into the bucket and also backwash out when I lift the bucket.)


Clean water going out at the top

amazingly clean compared to the tank!

Here is the temporary drain connection

I plan to swap this out for a flexible hose so that I don't need to unhook the drain when I lift the bucket up to backwash the media.

You can see here that I only half filled the bucket


I will need to make some alterations to the tank lid to allow the bucket supports.
Right now I simply have a couple 2x4s across the tank and the bucket handle is supported by a small 2x4 set on the long supports. I'll sort out those improvements along with the flexible hose for the drain.
I think this might be a very handy way to polish water going out of an aerated mineralization tank, just try to avoid having an aerator directly under the bucket.

Makes sense and looks like a winner to me

I like that TC,great build...

I'm hoping it works well long term. I've learned you need to allow several weeks for any filtration to season before you know how well it stands up to bio slime.