Blue-Green Algae.

[wey2go]

Hi! My pond (was swimming pool) was green even before rainbow trouts were introduced.

Concern now is if I am to eat the trout, how do I know that it is safe to eat them? Somebody warned me of the blue-green algae (Cynobacteria Algae) which can be toxic.

[wey2go]

Sorry, I should not have posted this thread here.

[GaryD]

Hi Wey2go,

Don't worry, I'll remove the thread when you've found out what you need to know.

What makes you think that the green stuff in your pool is blue-green algae?

Most aquaponics systems will go through a pea soup phase on their way to maturity. I think I can recall you saying elsewhere that you'd been overfeeding.....this may be the reason for your algal bloom.

Gary

[wey2go]

Gary,

Thanks.

The pool was already green and thick pea soup before fish (rainbow trouts) were introduced. So, I think it is not a matter of overfeeding. It was an existing problem before fish came along.

I started thinking about blue-green algae after emailing with Joe from www.duckweed.com.au. He mentioned about not letting pets or children near the pond unless I am sure about no blue-green algae. By the way, he charges $120 plus shipping for his "Duckweed Kit".

Then I started reading more about blue-green algae. One of the symptoms is itchiness of skin in contact with water with blue-green algae. Skin on my shin has been itchy lately. But of course, it may be mere co-incidence as I suffer from hay-hever and apart from sneezing, I get skin irritation. Also, I did noticed occasional greaser kind of floating stuff on the surface of the water.

I am now trying to find ways to quickly improve the condition of the water in the pool. 2 weeks ago, visibility was under 6 inches (cannot see my finger tip if I put my hand into the water past 6 inches). After 2 weeks of running 2 pumps (16,000 lph and 6,000 lph) and one of them through a 72W UVC, visibility has improved to about 2 feet.

Also, started running water through an OASE Biotec 18 pond filter (rated for up to 40,000 Lt pond with fish and my pond is about 30,000 Lt) last Thursday. It will take time for the filter to start doing its job.

I have been manually scooping out floating clumps of algae from the surface almost on a daily basis since running the UVC.

I have been looking locally for Duckweed and found them in my local Bunnings store (as a "by-product" of Water Lettuce). They sell the Water Lettuce and not the Duckweed (both type Azolla and the other one, roundish/oval small leaf). Got some from them but very small quantity. So, need to get them to multiply really quickly now.

Also, problem with salt in the pool water (was a salt-water chlorinator pool). Duckweed may not grow properly in there.

[GaryD]

Hi Wey2go,

What do you get for the $120.00?

Gary

[wey2go]

This is what I got from his email. I have not asked more as I think $120 is quite a lot to pay for Duckweed.

Quoting Joe &/or Kerrie Baker <jkagencies@gmail.com>:

> Hullo Wey
> You need to .live in Australia, then I can send it to you, I have two
> species Lemna Desperma and Lemna Landoltia I recomend Landoltia as it has a
> slightly larger frond, if you tell me what you want it for I can probably
> advise further.
> It will cost $120 plus postage.gets you advice notes, duckweed & and
> fertiliser as you establish it
>
> Give me your home phone and I shall call you, I get charged too much when I
> call mobiles
>
> Regards Joe

[mikkey]

Does anybody know what type of salts and the amounts you can put in an aquaponics system to prevent or slow down algae?

[fishfood]

Hi salt wont slow down algie you need to shade the fish tanks

[nick]

the only other thing that I have heard that has an effect on algae is barley straw. For your size pool/pond get a couple of bales and put them on the step. As they break down they excrete substances which inhibit the growth of algae,
CHeers Nick

[Dufflight]

Once your system cycles the aglae naturaly goes away. It hits a critical mass and dies off. It takes some work in keeping an aglae bloom going when breeding fish. I don't even worry if my system goes green after rain. A few weeks and it goes back to clear again. I can speed it up with a filter.

$120 for duckweed you can get for free in most places. And the special fertiliser is any ammonia source. Fish is a good one.