Controlling pond algae

[wayner]

We just put in a waterfall and pond that are completely separate from our pool and spa. The pond and waterfall has just been running for a week or two and we have put a few goldfish in the pond. The pond has just got a very large growth of green algae both in the pond and on the waterfall where the water travels.

Any ideas on the best way to control this that is not toxic for fish?

Eventually we will add water plants, etc, but there isn't much point in doing that at this time of year since winter is coming. The waterfall will be shut off for the winter and a bubbler will be installed to keep the pond from freezing.

 

[JoyfulNoise]

Algae is growing because the water has detritus and organic matter in it. You’ll need a pond vacuum to clean it all out and some kind of filtration system or else the water will become deoxygenated and the goldfish will die. I would not restock the pond until you get some kind of plant based filtration established. Even with some plants you’ll still need to vacuum and filter the pond water occasionally.

Did the builder install any kind of filtration system?? If there’s no filtration of the water, it’s going to be hard to keep the water clean.

Look up “natural swimming pool” on Google for ideas on how a pond is managed with coarse sand filters and plant based regeneration zones.

 

[wayner]

Yes there is a filter system for the pond - I think this is the unit: EZ-PRESS 2000 Pressure Filter . The waterfall and filter have been on for a little over a week and the fish have been in the pond for about a week. There is also a skimmer system to help to collect leaves.

We have had an unseasonably warm October here in Toronto but that looks like it is now ending and we will be back to more seasonal weather which will likely see the water temp drop from the 60s to the 50s or below which will likely help to slow the algae.

 

[JoyfulNoise]

Unlike a swimming pool, a pond with live plants and fish is much more difficult to take care of. You’ll need to have test kits for nitrates, nitrites, ammonia and phosphates. All of those parameters require precise control to keep water healthy and fish usually require a tight pH range to stay alive. Nitrites and ammonia are killers to fish while nitrates and phosphates are algae nutrients. Nitrites, ammonia and phosphates can be controlled with multi-component chemical filtration systems but nitrates can only really be dealt with using fresh water exchange.

You may want to join an aquaria or pond forum to get exact help. Around here, algae is controlled by one means - lots of chlorine! Not exactly helpful when it comes to fish and ponds.

 

[wayner]

Around here, algae is controlled by one means - lots of chlorine! Not exactly helpful when it comes to fish and ponds.

That may depend on how you feel about the fish!

Thanks, I will look for such a group.

When I was a kid we lived in a house that had a waterfall that fed a pond, although we rarely ran the waterfall as we didn't want to run the pump and also lose water. We never worried too much about it - about twice a summer we would catch the fish with a net and put them in a big tub. We would scrub out the pond, vacuum it up with a shop vac and refill. The goldfish got quite large, multiplied and survived the winters.

 

[pooldv]

Here's a pretty good koi pond forum. Koiphen.com