Backyard Aquaponics
A place to discuss aquaponics

Sorry I'm gonna give numbers in imperial as that is what I know (though in the useful info section, there is a thread I started with rules of thumb that probably has the numbers in metric)
Anyway Air.
1 CFM (cubic foot per minute) at 2 PSI per 400 gallons of fish tank.
So that would be an air pump that can deliver 1 CFM per minute then it takes 1 PSI (aprox) to push the air through an air stone and another psi to push air down 28" below the surface of the water. Unfortunately, for a system with a volume like yours, you might need a blower instead of just an air pump. I manage to keep my system happy with a 60 watt air pump that gives me 2 CFM at 2 PSI and that is hooked up to the battery backup.

Thanks TCL... was looking for those figures...

Yep Rupe, definately going to cover the filter boxes. I am filling with bio balls, with Jap mats on the top for the spray from the PVC to travell through to filter more solids.

Thanks for the different air tips, I'll check them out.

Some good news and bad.

4 days after installing the new filter boxes the pond is perfectly clear. It really was just suspended solids which have now been caught by the jap mats/foam in my new filter boxes. Obviously the 2 growbeds just aren't enough to filter the solids on the pond (1:1 or 2:1 ratio is more like 1:20 for me). Not a long term solution for me cos I don't want to clean them out every few days, but will do util I am able to reconfigure everything and through a few more growbeds in.

Now the bad news, I tested my 3 water sources (rain water in concrete tanks) and they are all alkaline, maybe 7.8, 8.2 and 8.5. My best guess is the concrete tanks are leaching somewhat into the water and causing the alkalinity? With my pond at around 8.5 - 9.0 I don't really want to add more alkaline water. Anyone know of a way to move the ph of large volumes of water, or should I just mix it up in barrels with HCL to bring it down?

Well, that solves the mystery of the high PH. Since you don't have concrete or limestone in your system the PH should gradually drop, jumping whenever you add more stored rainwater.

I wouldn't worry much...

Others will correct me. I'm probably overlooking something. *grin*

Nice to have the water clear again!

Have now added 4 litres of HCL over the past 2 weeks and still can't seem to get the ph down. Seems to be reading around 8.5 coming out of the growbeds, and around 9.0 at the other end of the pond (those coloured charts are hard to read!).

Oh well, I'll keep trying with more HCL, sounds like time alone may do it anyway. Ammonia seems to have dropped from 0.5 to around 0.25 so thats a good sign. Fish seem fine though hungry (follow me around) having only eaten once in 2 weeks.

Finally got my ph to around 7 with HCL, but Ammonia is up to around 1 (have only fed twice in 2 months). Solution is more filtration, so I picked up 2 more BYAP grow beds 3 weeks ago. Unfortunately so far I have only managed to push them off the ute, and roughly in position. Frustrating when children and other non AP things get in the way. I'll get them hooked up over easter anyway and should hopefully solve all my probles, which will be nice!

Two new BYAP growbeds up and running, water crystal clear within a day , so lets hope the extra filtration brings the Ammonia down from 1 where it has been sitting for months.

Off to B to stock up on winter vegies given my tomatoes are finally showing signs of slowing down.

Plumbing Help Needed!

I seem to be having a problem with the plubing on my drain from my growbeds. No doubt I am doing something stupid, so if someone can please point it out it would be much appreciated.

Essentially the higher of the two growbeds is not always draining, even though no blockages , is this an airlock? When I take the drainpipe out it releases something and everything drains. I can also notice water shooting up out of the drain pipe, and a gurgling sound.

I have attached a picture of the drainage, and where it returns to the pond (which is actually higher than the bottom of the drainage pipework, but lower than the growbeds).

Any help muc appreciated - I'm not keen on going out and finding a few thousand litres have overflowed!

I would say its getting an airlock put a tee just under the grow beds and a pipe up the side of the growbeds to 1 in above the top

Yep, stick in an air vet or two and see if it solves the problem. If the elbows are not glued, you might even put the T there and then run the open side up to and air vent pipe up higher than the grow bed, if that solves the problems then you know it was an air lock issue.

Thanks for help, air vent did the trick nicely.

Another koi death yesterday (9cm healthy looking). Checked water and my ph still high (around and ammonia still close to 1.0. Those readings have been pretty steady for the past month, and the extra filters and 2 extra grow beds have cleaned up all solids (increadibly clear all the way down to 1.5m) but can't get that ammonia reading to drop.

Now I think I know the answer before I ask the question, but I simply need more filter capacity right? I am still only holding 30 koi between 8cm and 40cm (only four big ones above say 15cm though), and ~ 20 babies that bred (around 4-5cm), plus 3 10cm silvers. Thats in 20,000 litres, with 4 BYAP growbeds and 3 home made pond filters.

I would have thought that was plenty given the low fish stocking but they always talk about koi being 'dirty' fish. The guys at BYAP guessed that even though my grow bed / figh tank ratio is way out, 25-50 fish per growbed would be what I wanted, but I'm obviously well under that level and still high ammonia.

Anybody got thoughts or can confirm mine? Not sure I could talk my wife into a couple more beds so soon after the last extension!

That smiley should have been ammonia readin of 8...

Correct that, ph of 8!! Too early in the morning... anyone want a 7 month old who has given up sleeping?

Do an ammonia test on something other than your pond water and make sure the test kit is working right. Like test your drinking water to make sure that has an ammonia reading close to 0 and then perhaps mix something up that should have a high ammonia reading and make sure the test kit shows it. I would think that your ammonia readings should be lower by now too unless there is some buildup of decaying matter somewhere in the system or one of the bio-filters that is just kicking out large amounts of ammonia at an alarming rate.

Good luck sorting things out.