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You’ve probably heard the saying, “oil and water don’t mix”, and that’s certainly true. A lot of people however don’t stop and think before they apply certain things to their pond in an effort to control algae. I’m not being critical here, it’s simply a matter of having the attitude that you want the stuff g.o.n.e., and no one can blame you for that.
The problem is more headaches can come up when you start trying to use products that really don’t go well together. There likely won’t be any explosions or anything dramatic, it’s just that you may not get the results you want with the algae.
So let’s talk about a few of the more common things that don’t quite jive when you’ve put them together in your pond.
UV Light And Beneficial Bacteria
UV or ultraviolet light is an effective tool to use against green algae problems in a pond. The single cell algae can create a pretty ugly look in the water, but UV light can kill or damage a lot of these little critters, along with other pathogens that float along in the water as it passes through the device. The problem is, there’s no way to tell it to leave the good bugs alone and kill only the bad ones. So good bacteria can be affected by UV too.
There’s a sensible way around this problem though, because if you have a biofilter working in conjunction with the UV, you’ll want to use bacteria to prime the filter from time to time. So here’s a good rule of thumb. When you’re adding bacteria into the pond system, be sure to turn the UV light off for 24 to 48 hours and allow the fresh bacteria to circulate throughout the system and into the biofilter more specifically. After it’s well established there, and in parts of the pond body too, then UV can be turned on and you should be good to go. Any free floating bacteria will still be affected of course but mainly you want it colonized in the filter and pond body where it will do the most good.
Copper Algaecides And Beneficial Bacteria
Now you may be thinking, these good bacteria aren’t very hardy critters if they can’t take a little light now and then. In truth though they are tough little things, but they are living afterall , and therefore, can be damaged by certain applications. So like UV, the same could be said when you use copper, or specifically, a copper algaecide to kill any algae directly. When you do this, you also kill good bacteria.
Before I get too far along here, let me stress that I don’t think any small pond owners should use much copper in a small pond at all. Copper Ionizers are used more commonly now and when they can be used safely that’s fine. Ponds without fish should have no problem with copper usage, but with fish, there is a risk of loss if copper levels get too high. Then again, if you have copper floating around in a pond, it will usually damage bacteria anywhere it’s present, meaning that the colony in a biofilter isn’t really that safe either.
So I see copper for a small fish pond as a no-no for the most part.
For large ponds there may, at times, be a use for copper algaecides but they are not the first line of defense against algae. I try other things first of course, and if one is required to clear up a pond, in a perfect world, you would likely want to follow up with some good bacteria supplementation a few weeks after a chemical application.
One of the biggest problems I see in large, old, ponds that have been treated with things like copper sulphate or Cutrine is a large degree of muck, sludge, and dead algae at the bottom. Common sense will tell you that this decaying stuff will only lead to more unwanted growth at the surface, yet the only way to reduce this build up is to either dredge the pond out, or use good bacteria to reduce the build up of organic debris. When you use a copper algaecide, it will bring this natural cleaning process to a quick halt.
Koi Fish And Desirable Plants (sometimes)
Quite often you’ll hear me suggest people use some good bacteria along with floating plants to help provide shade on a small pond. Doing these two things will often help with algae problems, and any number of other things, and it’s very wholistic. I mean who would have a problem with a few good lilies floating around?
Well in truth, some Koi (not all) will eat just about anything they can get their lips on, and desirable plants are not an exception. So rather than go overboard with plants to start with, it might be a good idea to test a few out with your current fish stock to see if they’ll tolerate a bit of foliage amongst them.
Good plants are such a powerful tool to use in keeping a small pond cleaner that they are worth the effort, but don’t be shocked if now and again you find a Koi munching on one of them. It’s not the end of the world, but down the road, you may need to look for other ways to shade the pond a bit.
Any Algaecide, Heavy Algae Growth, And Fish
Finally, this is a precaution we talk about a lot, but it can never be stated enough I think. If it saves one fish it’s probably worth the time to write this. No matter what type of algaecide you use, and this goes for the copper based one’s like Copper Sulphate, Cutrine, or even aquatic herbicides for large ponds, and things like <