Backyard Aquaponics
A place to discuss aquaponics

Okay.

Don't think Don is near the pea soup stage though?

From what I've been reading from people in the know, if you have 50cm visibility (Secchi Disk) or better things should be fine. When you get to about 20cm visibility it is serious HSM

My recent visit to a hatchery (and some of the pics Rupert has posted) show that it takes a lot of algae, or a rapid change due to inflow or climate, to cause any real problems to fish... IMHO algae is seen as a bigger problem than it really is...within limits of course.

Much of what you're saying is true Myles.... for pond based aquaculture.... recirc tank systems (hence AP systems)... are different though...

... and algael growth is actually discouraged, as the small (relatively) tank capacity volumes make it too difficult to manage algae....

Also, algael blooms are utilised in pond culture as a supplemantary food source and the main method of bio-filtration....

Not applicable to recirc tank or AP systems where we utilise external bio-filters to deal with ammonia/nitrate conversion...

Algae in such systems swings pH, DO levels far to quickly due to the small volumes, and make the use of algae blooms almost impossible to manage....

Different strokes for different systems/technologies....

Not suggesting Algal Blooms aren't a concern - suggested that some greenness is not a concern, even in a recirculating tank system - my opinion, take it or leave it

Would be genuinely interested to know of any commercial operation that is operating with tolerance of algae Myles....

Other than those running larvae production/hatchery tank systems... I've not heard of any....

Have you come across some that are/doing experimentation along these lines... ???

Can you link at all???

Not what I've been reading lately Rup, but there are "Greenwater Tank Culture" systems - you probably already know about? Not AP, but the principle suggests that green ain't all bad...

I've got Uni Staff access to various research Journals etc. - where I do some of my reading

But to answer your question, no I don't know of any commercial/experimental operations that are specifically running algae in an actual AP system... Lots of BYAP'ers probably do though

Nah, didn't mean "commercial" AP systems Myles... meant "commercial" recirculating aquaculture facilities... besides, don't think any "commercial" AP system use greenwater culture anyway.... or not as yet anyway...

Greenwater tank culture is the controlled growth of plankton and algae held in constant suspension.... and at specific pH values

It has proven to be succesful (in relation to clear water culture) in hatchery rearing of larvael stages... as I posted....

Yep... Greenwater Tank Culture is being/has been researched particularly with regard to Tilapia... in tropical and dry areas...

Tilapia primarily because.... they're primarily a vegetarian fish... can survive in water qualities. pH, ammonia. and nitrite levels that most other fish would die in within two hours...

The good doctor (Dr. Rockovy) at UVI has been doing so for years... not an unnatural progression to combine algae bloom techniques used in pond cultures..



But it involves daily removal of unprocessed fish feed, fish feaces, dead alage and excess plankton and bacteria..... a thick green sludge....



Disadvantages ...



So yes Myles it is a technique that has value in aquaculture systems... those which otherwise by nature would require water management tecniques such as external bio-filters and sludge/solids removers, constant monitoring and often water replacement....

All factors that involve significant upfront and on-going costs.... a reason why most aquaculture production is done by pond culture...

Despite initial high setup costs involved with land purchase... pond culture and algael bloom management is relatively cheap and easily managed within time and labour requirements...

Recirc tanks just don't have enough of an advantages to regularly and consistantly produce large quantities of fish... especially freshwater fish like Tilapia and Silver Perch etc...

The economics are changing... slowly..

But the point I'm making Myles is that it is beyond the normal backyard aquaponicist to run a recirc tank system.... in terms of equipment,knowledge, time and monetary setup costs....

And why bother.... the principles of AP take care of all the management problems faced by attempting to utilise algael and plankton blooms.....

The risks however of running green water systems for the backyard APer are huge.... rapid and total loss of fish... significant degradation of bacterial bio-filtration (until they get new fish)..... and little or know growth or even death of plants....

If you've got thousands and thousands of dollars.... the knowledge, the equipment, the room, the ability to pay for the power bills... the amount of room required for all the gear... all the relevant licenses to operate at the scale to justify it all... the ability (and licenses) to dispose of the sludge and byproducts.... and all day to constantly monitor and manage the water quality parameters involved....

Go for it..... but you'd have to do it on a large scale commercial basis..... and even most commercial recirc systems (to my knowledge) other than larvael grow out jsut havent found it to have sufficient advantages to make it worthwhile and for it to outway the risks....

Even pond based culture is frought with risks from algae bloom.... as many farmers have found and many stocks of dead fish attest to.....

For the backyard AP'er.... cover your tanks... avoid the bloom... smell the freshness of your tank water... watch your fish swim happily... your veges grow...

While you have a beer....

p.s. .... yep I deliberately highlighted parts of the quotes for "emphasis"

Yep, and I think you've completely missed my point... Perhaps I should say it again. A little greenness is not a concern... That is all I have suggested above? I actually think a little is a good thing, it helps keep things in balance. If the level of toxic nutrients gets to high, algae will help to lower them...

As an aside if you compare what you have said above you might find it is closer to AP then your willing to see:

External Bio-Filter - AP has them - grow beds
Sludge/Solids removal - AP has them - submerged pump/stand pipe
Constant Monitoring - AP some do
Water Replacement - AP some do if required, but not on a regular basis (why would you...)

Significant up-front and ongoing costs - not necessarily...

Sorry Myles, but I think it is you that has totally missed the point....

In AP we are trying to mimic nature and produce the optimal set of conditions for both fish and plant growth, with the least amount of cost and manual input...

In nature that usually occurs in crystal clear waters... not swamps and algael blooms...

Perhaps rather than use the word "external", I should have said "integral" to an AP system.

Yes the growbeds act as both bio-filtration units and solids removal units... that's the whole holistic beauty of aquaponics....

They also provide oxygenation of the water returning to the fish tank AND the removal of "toxic" nutrients.....

In a stable system, this results in a minimal amount of user intervention and monitoring... and a minimal amount of water relacement....

Many people have very limited knowledge of the nitrogen cycle and bacterial processes involved, the interactions between pH, ammonia and temperature and more significantly in this case the interactions between pH, temperature, DO and the relative time lines of algae bloom management...

And lets not kid anybody.... algael bloom management is a CONSTANT process requiring a degree of knowledge of not only the natural processes involved and the interactions between the varibles.... but WHAT TO DO ABOUT THEM....



An algae bloom in an AP system is IMHO... actually a sign that something is out of balance Myles...

There is no need to encourage algae in an AP system.... set up correctly it want occur... unless something changes... wont be a concern...

And the level of "toxic" nutrients wont be a factor.... because the system will deal with them... that's the integral beauty and benefit of the AP system...

Conversely.... encourage a level of "toxic" nutrients... an algae bloom.... and you'll put yourself (unless very knowledgable) in a situation that's likely to (and significantly) lower your DO, increase your ammonia and or nitrite loads and probably KILL YOUR FISH..... rapidly...

Considering the size (capacity) of most systems, the general level of knowledge and more particularly the fact that most people are working and can't monitor their systems throughout the day.... and then sleep when an algael bloom is most likely to cause problems....

Frankly I just don't see the need or the benefit.... and certainly can't and wont suggest or encourage most people to do so....

Look through the members threads and pictures.... other than initial cycling everybodies systems run near crystal clear and sweet smelling.... unless something or someone changes something...

And then everyone posts the problem and enters what's collectively become known as HSM...

Why would I encourage anyone, particularly those who may be new or just starting to try and run a system either in or near HSM...



Show me a way to setup a pond based or recirc tank system without significant up-front costs.... I'm all ears... seriously, I'm trying to do exactly that....

Perhaps I'm coming at this from the wrong angle Myles... certainly don't wish to come across the wrong way.... so...

If you think there is valid reason to run an AP system with a level of algae bloom, or your experience or access to information has lead you to this hypothesis, then please, for the benefit of all AP'ers share your information...

How would you trigger and maintain a level of algael bloom in an AP system?

What level of pH, temperature and level of "toxic" nutrients would you suggest is optimal?

What level of DO would be required and how would an average AP'er measure and monitor it?

When should we monitor all the appropriate levels?

And how would we correct any levels that may stray from the optimal levels required?

What level of feed would you suggest we increase or decrease if operating under conditions of algael bloom?

What sort of time frame do you think (roughly) we would have to correct any problems due to any swings in pH, ammonia and DO in say a typical 2000ltr system?

And what fish densitywould you run......
In my large GREEN ponds I can only run about 1kg per cubic meter due to the oxygen needs of the algie.These ponds are sechi dish checked twice a day and we have 2 X 6 horse-power petrol pumps on standby incase we need to quickly dump.
Sorry myles , I got to thinkclear water for AP is much better.

Rupert I'm not going to enter into this as you keep suggesting that I have indicated that people should be running with an Algal Bloom. I have said/suggested no such thing.

Perhaps your definition of an Algal Bloom and mine differ significantly. My definition of a Algal Bloom is not, nor is it anywhere near, the level that I am suggesting should not be seen as a concern to BYAP'ers.

I think the problem with running mildly green water is the high possibility of it turning into a full blown algae bloom very rapidly.

In AP the water should be crystal clear, unless something coloured has been added to the water.

Algae strings off the walls are fine, good food for the fish.

I see absolutely no reason to run any sort of green water??

Sorry Myles if I've read you wrong ... from the above mentions of secchi disk measurements and reference to the pictures I had posted....

It appeared that you were linking aquaculture blooms and management techniques to AP systems....

You seemed to compound that by reference to "Greenwater Tank Culture".... a technique that utilises very heavy algael blooms in constant suspension..... by large amounts of air.... think a fluidised sand filter, but with algae instead of sand...


Pond based algae amangement is all about managing light to moderate (at worst) blooms... the heavy bloom required for greenwater is a level that would have even the most hardened pond aquaculturalist panicing with HSM.

I couldn't understand what seemed to be your sudden change of heart considering that you had posted several posts in your swimming pool thread about avoiding algael bloom, taking steps to avoid it utilising barley bales and a pondering that such blooms may have been responsible for swings in your pH....

Thought perhaps you had come upon some new information through your reading....

Did try to point out that IMHO, no bloom is necessary or beneficial in any AP system... is often a sign of imbalance,is counter-productive in terms of pH and DO... as you yourself allude to in your own post... and downright dangerous in terms of most peoples knowledge and ability to respond..

I stand by my comments, for the reasons I posted... was happy to seek other peoples opinions as to their views though if other people were doing otherwise and posted a poll accordingly....

Hey, each to their own...

Funny part is... with the size of your swimming pool system... with a small paddlewheel aerator, you probably could (nearly anyway) run your system like a pond based aquaculture....

Bloom and all....

Bloom'in heck (or FFS)...Rupert, you take things so out of context or read way to much into what is said?

I've not mentioned blooms anywhere in this thread except in response to you suggesting that I had?

I only mentioned Greenwater Tank Culture in response to your direct question regarding systems that tolerate Algae...

I don't have an Algal Bloom in my pool, far from it. I've had very minor ~ 0.2-0.4 pH swings due to the algae alone over a 24 hr period (this is not a bloom!!!) - early am reading vs pm reading. The issue I had was trying to bring down the overall pH using HCl because I had wrongly guessed that buffering or leaching were causing the pH to be driven back over 8's. This is a system starting up, it will take much time and patience...

I fully intend to swim in the pool, that is the main reason I'm trying to ensure algae is kept under control. I have little doubt that I'll likely have some minor greenness in the pool, but I'm not concerned.

Algae Blooms are bad for AP - I fully agree - never said otherwise.

A clear water system (it still has algae in it) injected with nutrients will turn green just as quick as one that is already a little green.

My last word in this thread I promise