Backyard Aquaponics
A place to discuss aquaponics

Have you been taking any DO readings in the systems?

No, we took DO readings on all our systems a few weeks back and found them to all have great levels, I think they averaged about 8mg. They are all 15/45 timed system, so would have the lowest DO of those three styles of system we are trialling now so didn;t see much sense..

Plus it's just too much mucking around calibrating the DO meter each week to find levels are ok.. Might take a couple of readings later in the summer when the fish are bigger in the system..

Well at least you have an idea. Just wondered if there would be a big difference between the constant vs 15/45.

On a seperate note, if your Do meter goes out in the following years and you plan to get a new one, check out the optical do meter from YSI. Ive had a lot of hands on with DO meters over the years and this meter is great. It will hold calibration internally for 6+ months(can even change the probe and it will still hold cal), has a sensor cap (replace every 14 months) vs membranes that you change every couple months, has NO flow dependence and can store some 2000 readings internally. The only down side is the reading takes about 25 sec vs 9sec on some of the thinner teflon membrane DO models. It's probably a little more then most hobbyists would need but since you guys do a lot of installs and trials I would imagine it would be a pretty usefull tool.

Great thread, look forward to seeing the progress.

Not cheap either... and knowing that the levels in the kit systems provide the degree of DO.... not really necessary for installation purposes...

But yeah... the YSI is certainly a good meter...

I guess it would really come down to personal preference Rupert. I don't know how much trouble shooting he does for clients or how many custom set ups he's doing, if he's still tweaking systems to increase results, if he's still got fine tuning to do, if he's getting into large commercial sized projects, setting up further research systems, etc. It sounded like he doesnt really like dealing with the DO meter he currently has so I made a proffesional suggestion off of a product ive spent a lot of time with. Personally, I would still want a quality DO meter that is easy to use if I were in working in the aquaponics custom instilation industry and especially if I were looking to improve on previous designs. I know how it is to not want to use a piece of equipment because it's such a hassle to get a reading.

I've got nothing against the YSI meter Ryan... nice piece of gear....

Just making the point that the DO levels within the kit systems... which are fixed configurations... are known, and exceed oxygenation requirements... therefore, for installation purposes having a YSI meter isn't really necessary...

And all installations have additional battery backup aeration installed....

Sure for trials and experimentation... handy to have...

For most backyard systems isn't it a case of plugging an air supply in?

Unless you ARE pushing this limits, you would not use a DO mainly. Even then, get a bigger blower?

This is very interesting Joel. Having always been a chift pist fan and having run my system that way from almost the beginning, I must admit I am not only suprised but also disappointed. The growth rate difference is so significant that it would be hard to justify not changing the method if subsequent trials had the same result. I would not change on the basis of just one trial though because there could be a reason which is just not clear at this stage.

Keep up the good work.

Hey Veebs.... Yeah I feel almost guilty that the third one is doing so well... We aren't doing anything to try and create different results, I promise...

Though system 3 still has levels of nitrites and Ammonia in it, so it's not doing that well, just the plants look better..

Matt is going to post up this weeks results shortly, he has also been measuring water consumption and once again, I'm afraid that system 3 has used less water than the others.. Don't ask me why, I figured that with larger plants it would have used more. I guess it's more about water movement in the tank and evaporation from the tank.

How much feed is going into the system each day? The ammonia and nitrite processing efficiency is of some concern as you say - particularly given the system is not all that highly stocked (I'm assuming the 20 fish are quite small??). Given this is a trial you don't want to be changing the parameters, but in other circumstances I'd be tempted to decrease the time between cycles a little to see if this removes the ammo and nitrite, but has no affect on the plant growth rates.

We'll start doing up some graphs soon of the feed inputs. They are getting what they want to eat at each feed basically, rather than a set amount. I think they have had around 600g of feed so far in each system.

Also what are the water readings at the moment

Todays photos to compare....

Photos from above on the 14th Jan(today)...

Roughly measured water usage over the last week. Filled all the tanks up to the same point last Friday, when the beds were in the flooded stage, then measured the difference(loss) in water level this week.

The result were :

S1- 194L
S2- 212L
S3- 177L