Mark, As an Aquatic Biologist it is very nice to see someone in the decorative pond industry responsibly talking about some of these products the industry often blindly pushes. Two points to add with respect to fish. 1) copper will accumulate and kill fish long after coppery from either an ionizer or copper sulfate are suspected. 2) game fish species such as trout are far more sensitive to copper than koi carp.
Hi Nadine...it's possible. Copper is used to kill certain aquatic weeds, apart from algae, so if you have desirables, it will bear further research. I would specifically look up the plants you may have, and see if copper might affect them when treating for algae. I do think people who use the ionizers are able to have some plants and do fine. Probably keeping the copper level as low as possible helps too.
@corlejd first of all be sure to use some beneficial bacteria after you get everything started up again. This can help balance the pond, prime a bio filter if you have one, and generally keep the pond cleaner, which also might make it harder for algae to grow. Add floating plants if you can and be sure to visit our blog and you'll get a lot of other ideas on how to keep algae away in a small pond. Hope this helps!
It would depend somewhat on it's size as to what I would do about it specifically, but in general I like to start almost every pond with aeration and some beneficial bacteria to try to clean the pond up naturally. Often enough, doing so will begin to reduce the nutrients that feed algae growth and it will regress when those nutrients get low enough or are unavailable. To me, this is the most logical, first step to try, then the protocols may start to differ between large and small ponds.
I'm not going to claim to be a turtle expert but I would say as long as your pH is reasonable...6.8 to 7.5...ionizers or any type of copper related product should be safe to use. Turtles have something in their favor over fish...if oxygen drops low enough they can come out of the pond and still breath. So the main consideration would be copper toxicity...and again, that's related to pH levels mostly.
