Backyard Aquaponics
A place to discuss aquaponics

I have a slo with a solids filter which is one where the water is up through the middle and drops down inside an tube.

I know im getting solids in my filter because im cleaning it out regularly (once 2 weeks)

I have 19 trout in 1000l ibc and 12 goldfish in my sump

To catch fines i put a mesh around the outlet of the filter (first i put it on the inside of the filter outlet...but it got blocked overnight.
Then i thought maybe id put a fine net bag on the outlet which flows from fiilter into sump

I did this yesteeday and checke it today and was surprised to find some solids/mushy poop stuff in the bag.
The bag had also kind of blown up so i took it out as i think it was restricting flow.

My question is what do i do to get rid of these solids. I think from my reading these are suspended solids?
Is my filter not working well or do i need to add some other form of filter to get my water rid of solids?

You don't want the flow to stop because of a clogged up solids catch. Review swirl filters as they seem to work good. I'm just now making one for my system as it wasn't part of the original plan. Want to get my water back to clean again.

For settleable solids a Radial Flow Filter or a Swirl filter works well. For the suspended solids that won't settle easily some sort of sieve works better. This type of filter includes Drum Filters and Static Upflow Filters (SUF). Drum Filters are probably the best but are usually beyond the price range that most Backyard AP sorts are willing to pay. I'd rate the Static Upflow Filter as second best and that's what I suggest you use. SUF's work like a 3 dimensional sieve. Water comes into the SUF container that is filled part way with floating media - it enters at the bottom below the media and travels up through the media to an outflow at the top being cleaned as it does. You should filter the settleable solids first and then use a SUF for the suspended solids - that way the SUF won't clog as fast.

Here's a picture of a SUF I made before I put it into use -



Basically this one is a 20 gallon tank with a 5 gallon bucket inside. This next picture is what the inner bucket looks like before installing it. That mesh basket at the bottom gets some of the large solids before they enter the bucket -



Here are a couple of SUFs that are installed. The inflow is on the right side of the picture and is controlled by the white handled ball valves. The Outflow pipe is going off to the right below the inflow on both of these. The green atrium grate in the center of the filter that is surrounded by floating plastic media is where the water flows out of the filter. The drain to remove solids comes out on the left (you can see the blue handled ball valve off the back SUF coming out near the bottom) and goes to the pipe running along the ground (it's connected to a pump to send solids to a mineralizer (not yet built)).



You can clean a filter like this using air or some other method of agitation to mix the plastic and release the solids then just flush them out through the drain. You can mineralize the solids to add back into the system or you can just use them in the garden or compost pile.

The two SUFs here are pretty small (20 gallon), most I see are in 50 gallon barrels.

SUFs work well but they do need to be cleaned regularly. You can usually tell they need cleaning when the media rises because of the increased pressure. The one pictured above needs cleaning. You'll probably want to clean it before this though since you'll have more nitrogen lost as gas (this happens as the filter becomes more anaerobic)

A lot to learn but I hope this makes sense .

I really like the parabolic screen filter. If set up correctly it's pretty much a self cleaning filter.

They are not hard to make. Here is one [youtube]https://www.youtube.com/watch?v=h99pDa3vrSc&sns=em[/youtube]

Use a fine screen and make it big enough to easily pass the amount of water you are pumping with only 1/3 of the screen.

Keep in mind you might not need a filter. A media grow bed with worms is a good filter. Media and roots filter solids, Worms eat them. This might not work with heavily stocked system but I think it'd work for you.

+1 to the comment about maybe not needing a filter. Media based grow beds work for solids, as a biofilter, and as a mineralizer. Whatever you choose just design your filtration with your fish load in mind.

The "IBC of Aquaponics" has lots of systems just using grow beds for filtration - the link to the free PDF is along the top of the page you're viewing.

I haven't used a parabolic screen filter but if they are setup right I don't see any reason why they wouldn't do a good job and be easy to maintain.

Thks for replies.
So its between suf and screen filter.
I might opt for screen filter as it will be much simpler and quicker to add into my system so a good starting option.
An interesting video i saw online of a homemade filter is below- what do you guys think?

https://youtu.be/Ul_oPDh0gh4

See if you can figure it from this explanation first.

Both SUFs are fed by the same pipe - you can see it coming around the greenhouse corner in this pic -



The SUFs are rigged in parallel not in series so I can turn one off to clean using it's ball valve and the other still filters the water. Notice that the water is coming in the top pipe on each SUF and you'll see from the picture below that this feeds the area between the bucket and the outer tank. The water hits the bucket and flows around both sides then down to the bottom (dropping some of it's solids) before heading through the mesh basket at the bottom of the bucket and up through the media in the bucket, to the outflow at the atrium grate. The water flows out to the fish sump in the greenhouse - you can see the pipes headed out to the right in the first pic - those go to the fish sump.



The drains are also rigged in parallel and go to a pump (you can see the pump electrical cord in the first pic). The solids can be pumped to a mineralizer or out to the yard. That's all there is to it.

The pic below shows the drain setup and shows how the media is way up to the top of the Atrium grate because the filter needs to be cleaned. You can also see part of the pump on the left side.



One last thing - most people don't need a setup like this, grow beds work just fine for most AP systems. This was an experiment to see if I could replace the RFF component with these - the answer is yes but with more maintenance - exactly what you'd expect.

hi scotty,
i note that your inlet pipe comes in straight and is intended to hit the inner barrel and drop.

just wondered if you had tried turning this inlet so it becomes like a radial flow?
or wouldn't this work?

I considered doing this but in this case the mesh basket sits on the bottom of the container so I decided not to because I thought that the vortex would force the solids into the middle where they could be more easily lifted into the bucket. I'd rather have as many solids settle out to the sides and on the bottom as is possible. If the basket were off the bottom I would have set it up to swirl as you suggested because then the solids would collect under the inflow to the bucket . It may be wrong but that's my thinking on this.

Awesome Scotty. Now I have a much clearer visual on how the flow goes. I've been stuck because I was seeing the bucket thinking it was similar to my RFF, in some way. Now I see that the water drops to the bottom around the bucket then does the upward flow toward the bucket minus the solids that fell out. I can also now see why you suggested it when I was having difficulties with floating (suspended) solids. Thank you so much. Thank you as well Moiz sorry to hijack your thread. I hope @Scotty435 cleared up you questions as well.
Brian

Perfect Scotty, I wondered that as well. Now I'm wondering if with my larger sized filter if I should divide my space combining the best of both worlds such as Moiz asked? Luckily with my health issue I still have time to modify my filter before gluing it in place. Again, thanks to both of you.

I take care of a couple of pools and have often wondered about modding a pool sand filter for ponds, fish tanks and AP system. as long as one is not counting on it for bio you could hook up a hose to do a back wash and a small system could probley go six or more months before needing to back wash it. It's on my one day to do list.

I think you'd have troubles with algae clogging the sand filter enough that you'd have to back flush it quite a bit more often than every six months. Pools don't have anywhere near the organic load of an AP system but it would be interesting to see it done and see what happens. There have been some sand filters here that were run on an occasional basis and seemed to work but were geared more toward temporary or emergency use.