Backyard Aquaponics
A place to discuss aquaponics

Yes, you are right here Dasboot.

In the design I adapted, swirl effect happens at the bottom 1.5 feet of the filter tank below the media and bio-balls.

I have several gravel growbeds but using gravel on my filter tank? I am not able to rightly comprehend why one would use gravel in a filter design such as this.

It's just a tip of the hat.. Of course, a voila moment!

I was comparing the surface areas. One of the common criticisms of gravel is that it has a very low surface area relative to commercially made biofilter mediums. If he is going to be cleaning it regularly then obvioulsy gravel is a poor choice but I made the comparison to highlight that the string wasn't as good as he thought it was. Having said that and as I said before if he is happy with it then he is happy with it.

The reason I made the point was that I could just see some other person who new nothing finding out that need so many m3 of biofilter material and then seeing the string and getting some of that and then wondering why their biofilter didn't seem to be working (because it didn't have enough surface area).

Ok thank you Stuart for your correction you are always quick to set us right and your allways welcom here. Do you know how to calculate the Max flow a 55 SF can Handel before it is useless or is it a case where the faster the swirl the better?

Is there a optimin flow for a 55 SF?

Am I reading you right Dasboot you don't put anything in your SF? Your saying it works better that way? Was using pet bottle covers because they float and hold up some duck weed in the filter but they are toxic so I am looking for alternatives. If the SF works better empty that's all I need, I will be doing some Side by sides once I get the off grid power though. So that should be interesting.

BTW I got 4 more deep cycle batteries for a total of 5 batteries they are eveready brand. I payed for (4) 250W pv panels from price mart. Not the best brand (sun force) but its the best deal because I got a10year warinty on the pv and 2 year on the batteries. The 4 panels, 4 battery's and 2 charge controllers cost me about $3500 us.

Sorry Stuart i have been miss quoted there,i Totally agree with you,I just couldn’t understand why someone wanted to put anything in a swirl/radial flow filter,i can understand a ring of Matala at the surface on this type of filter,but can’t see the point of string or gravel
In the past,Pond keepers tried and did use Bailing twine as filter media,the stuff that used to hold hay bails together. that didn’t work either,one that did work was the plastic strapping you have around parcels,it has a dimpled surface so that the clamps work correctly,this helped the BSA.One company so say had this strapping manufactured from fish safe plastic and marketed it as a filter media

Spot on, Andy. That's indeed what it is.

Damian, why do you believe that PET bottle covers/caps are toxic?

A dude name Steve on this forum told me so, he is right most of the times. I must admit I never checked up on that.

Adding a floating media is an attemp to remove the 'unsetable' solids from the water by basicly knocking them out of the flow.

Witch leads me too a idea. My main exit from the 55SF starts top center with a elbow facing up. What if I was to turn the 2in ellbow to face down and put in a 6in long peace with slots or holes in it and cover this with a panty hose or sock. That way I could cleanthe system

Adding a floating media is an attemp to remove the 'unsetable' solids from the water by basicly knocking them out of the flow.

They use fluidized sand filters on swimming pools and Koi ponds,the moving sand mashes the particles,[most probably not the technical term] the bacteria living on the sand do the rest.Floating media do knock the bigger particles down but then let the small particles through.
The sock ideal will block very quickly,depending on the load, hours to minutes.

Well maybe if I turn the sock to point up, that way as it clogs the water level rises, maybe a sock is to fine of a mesh, would need something with a bigger hole size.

What I am thinking is to have small washable filters that you can change daily and stock pile maybe sun dry and let the waste turn to dust and fall off or put in a washing mashine at the end of the week and rotate your filters.

They could be disposable.


Stuart I am still wondering about calculating the optimal flow for a 55SF can you point me in the right direction?

The Earthan Group have a set of calculations on there site regarding swirl filters and radial filter flow rates,retention time etc,with having a look. Ryan has already mention this in your thread.

For things like swirl, drum, radial and other filters I go by the manufactures specs. The barrel swirl filters are too small for the stuff I'm working on.

If you really want to go Mega big with AP you don't want to be grading fish, just takes to long. You will have to grow from fingerling to harvest in the same container to be profitable. On the other hand you want to maintain a stocking dencity that can produce a high enough waste stream for the plants, you can control stocking dencity with the amount of water in the tank starting out around 1 foot for fingerlings and ending at 4 feet at harvest. That situation I just discribed limits the size fish tank in a Mega big AP system to sub 10 foot diameter. By Mega big I mean so big the people tending to it never see the whole thing. 2000+ fish tanks.


Such a system would have to be modular and will be on sloped land. sub 10 foot diameter is easler to get the tanks level and I think 55sf's will work just fine in such a system.

I don't intend to be rude I am just stating what I believe to be a fact.

The above post is another demonstration that you just don't know what you are talking about.

Grading is essential in most commercial operations because it increases efficiencies. Space, capital, energy, food and a whole bunch of other things are used more efficiently in many systems that rely on grading. Yes it comes at a cost of labour but for most commercial operations it is worth it which is of course why it is standard practice in commercial operations.

Stuart you are not rude lets just disagree on this one. But I know for a fact if you ever hit the 10000 tonne a year fellets your fishtanks will be limited by this natural problem.

For big by today's standerd not so much. You can make the biggest fish tank possable.

Ok

Today mankind is building cities from scratch, if they ever did desire to build a city that uses AP as the food source the AP system will definately not have mega large tanks. That's the truth.