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View Full Version : Malachite Geen is carcinogenic



Biggles1212
07-25-2010, 12:23 AM
Hi. I've set up an aquaponics system at home. After my pilot plant using a 40 gal drum and a few grow beds which ran very well, I then up sized to a 5000L system. Things went even better. I only had 10 koi and 3 Red Breasted Tilapia. The Koi came from a shop and the Tilapia from a dam near by.

I then went to a friends farm and loaded approximately 30 kg of fish of varying sizes and brought them home. Within days fish started dying. I put Ich Medicine containing Malachite Green in the tank. Unfortunately I did not read the whole label properly. At the bottom it says not for use on fish that are intended for food. The WWW says Malachite is carcinogenic.

Is there a sure fire way to decontaminate a tank? Does anyone know if the Malachite Green embeds itself in the plastic. So far my course of action is to throw the whole setup away and start again.

dufflight
07-25-2010, 02:38 AM
Not sure. I'd be doing water changes until I found out tho.

Biggles1212
08-13-2010, 09:46 AM
OK, I found out that activated carbon does remove the toxins from the water, but not all activated carbons are created equal. Generally the stuff available in Pet Stores in South Africa is no more than charcoal which won't do the trick. Some bloke has started an activated carbon factory in a nearby town to me and so I've been able to lay my hands on the real stuff. It's the same quality used for water purification plants.

This however does not remove trace elements from fish so I'll breed the fish and continue with the fry. The trace elements in the full grown fish if there are any then will be negligible.

Hindsight is 20/20 vision they say. In future my fish will be transported better and stay in a separate tank first. I noticed the really small fish didn't stress as much so I'll make sure I get fry the next time too.

Everything you rush in aquaponics becomes a nightmare.

davidstcldfl
08-13-2010, 07:30 PM
Hi Biggles1212.... :D
I don't know if I said 'welcome' or not (?) We've had so many new folks joining....I can't keep up. I guess that's a good problem.... :)


Everything you rush in aquaponics becomes a nightmare.
You sure got that right !

badflash
08-14-2010, 06:28 AM
Welcome! You'll kill a bunch of fish in the process. Par for the course. Now you know not to mix wild and established fish. Best to keep a single species in a water system.

Biggles1212
08-14-2010, 08:39 AM
Last weekend my plastic welding machine arrived and the plastic sheets arrived this week, so I'll be building my "real" grow beds now. :D My original setup used a 210L system with three grow beds (made from tubs), then the 5000 L tank with two large grow beds (made from tubs again). I added onto the system using the rough tote bins, but had a terrible time trying to seal them. :cry: The rough tote bins are flimsy and you need real tank adapters to seal against them. Fortunately the fish story was learned early in this game. I've got a 6.5m x 24m greenhouse to build and a massive system planned. The filtration has also been difficult to sort out, but I've finally worked out a minimum maintenance system.

I'll be keeping to the Tilapia for stock fish. Great to eat and reach 4.5kg @ 450mm. Not to sure how I'll catch that one. I've also got breeding tanks in mind so that I can supply myself with stock. As soon as possible I'll start a page on the build from the beginning. I appreciate all the help offered here.

badflash
08-14-2010, 11:30 AM
What part of South Africa are you from? I've heard of cold tolerant tilapia in the mountains. They are supposed to survice winters with ice on the surface.

Biggles1212
08-17-2010, 09:38 AM
Badflash

I'm from Phalaborwa in the Limpopo Province. Our town borders on the Kruger National Park. Our town is nick named "The Place of Two Summers" It was the coldest I've ever remembered the other day, we reached 7 degrees Celsius. Last December in the height of Summer we had temperatures as high as 45 degrees Celsius.

It rarely ever snows in South Africa. But Tilapia aren't that active in the cold. I've got a few fishing spots I love to go to and this winter the action just died, which isn't normal, our winter was just colder than normal. Except for a few weeks ago. I was collecting the Tilapia and we were offered an opportunity to fish. From the big dam there wasn't a single bite, but in the breeding dams I was casting and catching immediately. The only reason I believe is the water temperature.

My tanks are buried 2 meters into the ground. Makes cleaning a pest so I'm going to have to devise a clever plan to improve it. I saw your How to for the bead filter and it got me thinking. I'd like to position my filter next to my tank and feed a 4" pipe down to the bottom of the tank, then allow all the grow beds to fill up the tank and thus feed up the pipe into the filter. I've been ranging in filter mediums ideas from river sand to filter cloth used in industrial applications. A few years ago I designs a filter for a Zirconium Basic Sulphate plant that looked like a chest of drawers with filter cloth on the bottom of the drawers.

It allowed one to remove a drawer, clean the cloth or exchange it and then replace it back without interrupting the process. Oh well we'll give some thought.

jackalope
08-17-2010, 05:03 PM
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jackalope
08-17-2010, 05:11 PM
Malachite green, as well as Methelyne Blue will stain the plastic - the reason I know this is becuz when I raised and sold tropicals, if you didn't take the air tubing and the corner filters out, it would be stained for months (sometimes permanently - I think I've still got some green-colored tubing around here somewheres). I don't know of any way to remove what is embedded into the pores of the plastic, maybe a strong chlorine wash, but at the same time, I'm not sure that whatever is doing the actual staining is the carcinogenic, nor am I sure that there is enuff carcinogens in the plastic to do you any harm at this point. At least you know now not to use those chemicals in a plastic tank .... use a glass aquarium/tank for all nursery/hospital tanks, just to be on the safe side! ..... and yes, you have to remove all of the activated carbon when treating fish with medications, as the carbon will remove the helpful, as well as the non-helpful chemicals/diseases in the hospital tank! I have some green-stained corner-filter-floss filters Clik ;) (http://www.aquariumguys.com/economy-corner-filter.html) that I use for my hospital tanks.