Vlad to be honest i have no idea off the top of my head, which is bad, because I know I had a test on it at one point. I will look it up in Noga and report back. I just know that copper is a big no-no with trout, while I used it to control snails in catfish ponds that had bluegills in them. Snail control was important due to trematodes they shed that the catfish receive. Ultimately it just makes the fillets look bad.
Also to finish a topic from another thread, I went to get you a Noga book and send it to Serbia for you. That was until I got the shipping quote of $270. I am not a rich boy either, but I like to help people when I can. Let me see if I can get you an electronic copy.
Matthew, while I tremendously appreciate the gesture, I, like you, am very far from what anyone would call wealthy in terms of money. I wouldn't feel right accepting such a gift. $150 in itself is a lot of money. The shipping alone is almost a month and a half's average wage in my region of this country. Again, thank you so much for even thinking to do something like that. That was very kind of you.
I found an old circular (Illinois circular 131 from 1978) I had read a while back that dealt with how alkalinity (and other water parameters) may affect copper toxicity in trout, bluegill, catfish and some others. (To make a long story short, the copper complexes with the bicarbonates thereby reducing the amount of soluble copper in the water. Other thing like organic acids or other organic particles may also form complexes with the soluble cupric ions and cause it to precipitate out of solution also reducing the toxic effects of Cu).
I don't think it is copyrighted and you may find it interesting/useful. http://www.isws.illinois.edu/pubdoc/C/ISWSC-131.pdf
Maybe certain fish are more sensitive to such things than others?
So to rephrase:
Alkalinity effects the saturation limit so to speak of dissolved metals in water. The higher the the alkalinity, the less dissolved copper the water will hold.
Calcium and magnesium compete with toxic metal sites on the gills, so they can "buffer" the effects.
Thanks for the paper. I'll add it too the library. FYI my Noga emails were bounced back. I'll keep trying anyway.
Yup, that would be about the gist of it. The copper is all there in one form or another, just not in it's most toxic (cupric soluble) form. It may precipitate out as malachite or azurite at high carbonate (alkalinity) concentrations, or tenorite at lower concentrations.
It's good to know that calcium and magnesium can have that type of positive effect (since neither seem to form complexes with the copper the way alkalinity does...well maybe to a small extent...nice to know that they help mitigate the negative effects in their own way).
After you rid yourself of slugs, why not ring your system in copper. On the outside of the tank?
Wow! I wasn't aware of that....I just wrap it around the outside of the grow bins, so I think I'm safe...something to think about, for sure though.
Cheryl Sterling said:
Have you tried old left over copper wire? I was having a major slug problem for awhile...copper seems to do the trick!
My systems have been over run with slugs lately as our rainy season started a about a month ago. We have several species of slugs here. We have large flat ones that can get 3 inches ling. They live in the rocks around the systems by day and come to eat out of my troughs by night. We also have little ones that max out at 3/4 inch and have been getting into my celery. They are eating craters into the stalks. They seem to stay in the craters during the day and come out at night to eat the tops. They have made my celery and chard unsellable. They well also hide in the cinder during the day.
I have been waging war on the slugs for the last week and am finally getting the upper hand, I think. In the systems I started using sluggo in small cups covered by a foil umbrella to keep the rain out. I have also put it on the ground surrounding the systems. A few hours after placing the little cups in the system my daughter discovered them and began dumping them out all over the place. Sluggo is now all over my rafts and in the cinder. She even fed it to the fish in the sump!! That was a week ago and I have had no fish casualties. Everything in the systems is looking good and does not seem to be affected at all so far. The slugs have eaten the bait and are dying all over the place. I also surrounded all the systems with rock salt which kills the slugs as they crawl over it. There are dozens of slug carcasses around my troughs now. An added benefit of the salt is that it is killing all the weeds on the ground where I apply the salt.
Thanks. That's good to know - another source of free fish food.
Jon Parr said:
Good idea, George. Since I posted this I started raising some green sunfish, that love to eat the smaller slugs. So now I try and periodically get to the growbed early in the morning, and just hand pick and toss them to the greenies. Bluegill take them too
I've used 1% iron phosphate products like "Sluggo" for watercress snails without any problems.