Natural algae scrubber and another high 5 for WB

[JohnHuff]

I'm a long time pond keeper but an aquarium owner just this year. I like DIY projects and I've built a lot of DIY filters both indoors and outdoors for fun. My mantra has always been to build the simplest of filters.

So I've been reading up on aquarium algae scrubbers. It's just a rough surface over which you pump water over and shine light on. Algae grows on it which sucks up the ammonia, nitrites and nitrates. Every 1-2 weeks you scrape off the algae (the biomass which now contains all the nitrogen) and repeat. This isn't something I'd do for my tank because I don't like the idea of extra bright lights under the cabinet and the setup. I'd rather just a build a small refugium with easy to grow plants that don't need to be scrubbed off every 1-2 weeks.

After reading that I also realized I've had that setup for years for my pond. I have a natural waterfall and a stream bed that's about 3 ft long. Even though the stream bed is partly shaded, it grows a lot of string algae during the growing season. When the algae gets too much, I pull it off the bed and dump it under the bushes for fertilizer. So that's my natural algae scrubber: water flowing over a flat surface with light shining on it. That reminded me of a something WB said about streams being natural trickle towers and also that watergardens don't need extra filters.

So those of us with ponds, greenery and natural features, do we really need extra filtration? The rule of thumb is 1 inch of surface for 1 gallon. For small ponds, a stream bed of that surface area is easily doable. Why go through all that trouble of buying expensive and "worthless" filters, or even building DIY ones when all we need is a natural feature?

By the way, I also found this article that using green matter as the only filter can lead to pH imbalance.
http://www.koiphen.c...te-and-nitrates

Comments?

 

[addy1]

My stream is around 85 feet long, runs about 4-6 hours during the summer, about 2 hours at a time (one a timer) between it and the bog I have no issues in the pond, at this time lol (disclaimer)
The stream has 4 decent smallish ponds, 5 smaller pond/ water collecting areas, each has plants, algae, snails, no fish.

Sounds like I have what you describe. My setup works great, no real effort to keep the pond water nice.

 

[Craig58]

I think streams are great for many ponds and pond keepers. But again it depends on your goals as a pond keeper. If you want a Koi pond, a stream probably won't cut it. In addition, you will collect debris in a pond with just a stream. With no mechanical filter you will buid up silt in your pond on the bottom. After a while, that will need to be cleaned out. If your goal is a simple, work free pond, with a low fish load and a natural balance, a stream is great. But at 1000 gallons, you need 1000 sq. inches of stream by your calculations which comes out to a 7' by 1' wide stream. Or 3.5' x 2' wide stream. And I wouldn't suggest Koi in anything less than 1500 gallons really so you are looking a either a 10' stream 2' wide or about 6' at 2' wide.

So yes, I think a pond under 1500 gallons with a moderate goldfish load and you could probably do fine with the right mixture of plants and an annual fall vacuuming of the bottom. But I wouldn't suggest this for anyone wanting koi.

A key for addy is she keeps no fish. And she has a looonnng stream plus the bog!

Craig

 

[JohnHuff]

I think a stream can be part of the filtration system. It definitely isn't a mechanical filter but most people already have some kind of strainer/pre-filter to protect their pump so that shouldn't be a problem. I have 4 pre-filters that strain out most of the suspended stuff in the pond.

People can keep some koi in a less than 1500g pond. I have an 800g pond with about 25 fish in it. About 10 of that are koi, plus assorted small fry. They're all about 6 inches long or so. Over the growing season I had a shower filter, a mini-skippy, and 3 trickle filters running, plus the plants and the stream. Funny, I guess the fact that I had algae in the stream meant that my man-made filters weren't enough to convert all the nitrogen in the water.

 

[Craig58]

I definitely think a stream can be a great filtration system and a great addition to any pond.

Yes, you can keep some koi in a pond less than 1500 gallons and thousands of people do. But the vast majority wind up with problems. They fall in love with their koi and so add on filtration, or build a bigger pond, or have fish deaths, or have to cull out their fish and only keep favorites.. Or some combination of all the above. Basically they either get more into koi, or they wind up scaling back on koi.

10 koi in an 800 gallon pond along with 15 other fish will, in all likelihood overwhelm your pond in a few years as they grow. Maybe even in a year depending on the koi and pond conditions. Of course you can add filtration or cull some out. But you will have to do one or the other eventually.

Craig

 

[addy1]

and an annual fall vacuuming of the bottom. But I wouldn't suggest this for anyone wanting koi.

A key for addy is she keeps no fish. And she has a looonnng stream plus the bog!

Craig

Craig,
No fish in the stream or stream ponds, over 200 in the big pond, xxx rosey reds in the lotus tub, stray fry in the preforms. About 25 in the deck pond, all moved for winter though (deck pond fish).

 

[Craig58]

Ok. You do have fish. But lots of natural filtration with the long stream and bog. And no Koi.

Craig

 

[Waterbug]

I've found aquarists are by far the best source of information about ponds. You just have to scale, adjust for sunlight, temp, etc. But the amount of excellent data and experiments done by aquarists is a gold mine of info. There's nothing even close in pond keeping even in the more serious forums.

In my next pond, which I'm designing now, I plan to create a refugium which I think will work well for the kind of pond I want and solve some issues I don't want. Learned it from aquarists. Not much different from our veggie filters accept aquarists see the value of algae as a tool, as one of the best plants a veggie filter can have, more than pond keepers who seem to only regard algae one way, evil.

Every filtering system available has some downside for some type of pond. I just look at what a filter can do, has been shown to do, cost, size, etc., and if that's something that gets me the pond I want I'll consider using it. They're just tools.

 

[JohnHuff]

10 koi in an 800 gallon pond along with 15 other fish will, in all likelihood overwhelm your pond in a few years as they grow. Maybe even in a year depending on the koi and pond conditions.

I've had my pond for about 10 years now. I remember reading that fish growing to the size of your pond is a myth, but in all these 10 years, I have not had any fish grow to a foot long yet, I think 8 inches or so is the max. size of any of my fish.

 

[Mucky_Waters]

I've had my pond for about 10 years now. I remember reading that fish growing to the size of your pond is a myth, but in all these 10 years, I have not had any fish grow to a foot long yet, I think 8 inches or so is the max. size of any of my fish.

From what I understand about fish growth, fish release a type of hormone into the water they live in, and if the water gets concentrated with that hormone it will stunt their growth, but if you do frequent, and thorough, water changes the hormone levels won't build up and the fish will grow normally.
So the question is, how often do you do thorough water changes?

 

[crsublette]

There was a fella on koiphen aiming to build an algae scruber for a pond, but various aquariasts told him that the scrubbers would have to be quite large if he wanted algae scrubbers to be used as the primary filtration. Just look at the size of algae scrubbers vs the size of aquariums then think of how you would have to rescale this so it could be the primary filtration for a pond.

Sorry, very interesting. Found a bit of each reply for me to reply to. Fun thread.

I agree with ya Huff. I highly recommend keeping algaes of all sorts in streams not only as a supplement to existing bio-filtration, but I also think they may emit allelopathic chemicals that might just combat other algae species.

My stream is around 85 feet long, runs about 4-6 hours during the summer, about 2 hours at a time (one a timer) ...

With my stream and rock fountains, if I turn them off for just more than 30 minutes or so, then the algae dries up quick and then just flakes off; don't think they survive it. I don't know, there could be hardier algaes that can survive such envinronments; this would be something interesting to read about indeed.

In addition, you will collect debris in a pond with just a stream.

Even after pre-filtered water, there is still dirt and all sorts of other debris that eventually falls into the stream. Depending on the size of stream, a stream can easily have more surface area than a pond. Ugh, this is why I am going to mortar my stream except allow the rocks to poke out at least a 1/2 inche above the mortar so to allow a little debris accumulate for some algae to grow.

Over the growing season I had a shower filter, a mini-skippy, and 3 trickle filters running, plus the plants and the stream. Funny, I guess the fact that I had algae in the stream meant that my man-made filters weren't enough to convert all the nitrogen in the water.

That is alot of bio-filtration and if they're built as effeciently as I am thinking, then your pond will be able to handle a whole mess load of fish. It's how it goes. Quality and quantity of bio-filtration will determine the maximum capacity for a pond's ecosystem. I've also heard ponders in these setups have a pond turnover of at least 7 times a hour, with proper water current management, so to make sure any old water gets pushed through the bio-filters. Ya also have to remember that algae is a very prehistoric plant so it doesn't take much for the stuff to grow just a small bit somewhere.

Every filtering system available has some downside for some type of pond. I just look at what a filter can do, has been shown to do, cost, size, etc., and if that's something that gets me the pond I want I'll consider using it. They're just tools.

I think the major problem is CO2 and other chemicals emitted from algae that does cause a consumption in carbonate, which can eventually cause pH swings. However, I bet only on large scales where a ton of algae is present are the pH swings going to be a problem.

In my next pond, which I'm designing now, I plan to create a refugium which I think will work well for the kind of pond I want and solve some issues I don't want. Learned it from aquarists. Not much different from our veggie filters accept aquarists see the value of algae as a tool, as one of the best plants a veggie filter can have, more than pond keepers who seem to only regard algae one way, evil.

I have read of "algae tanks" used specifically as filtration for some big fish farms. There are huge tanks where only particular species of algae would grow. I have also read this done in aquaponics. In these systems, there can be a tank that is seeded with various algaes to "scrub" the water then the water is sent to pre-treatment tank to adjust pH before it reaches the main fish stock tank.

From what I understand about fish growth, fish release a type of hormone into the water they live in, and if the water gets concentrated with that hormone it will stunt their growth, but if you do frequent, and thorough, water changes the hormone levels won't build up and the fish will grow normally.
So the question is, how often do you do thorough water changes?

Not just water changes. I'm told there are other devices as well that will determine the absorption of such things. I'm told the size of fish just doesn't happen because the fish wants to. Yeah, it takes alot of finesse for a fish to get big. Each koi in the grow out ponds at Nishikigoi japan are given at least 2,000 gallons and very specialized food. However, the amazing anoxic filtraiton is told to have the proper devices to allow fish to grow up to 30" longs in just 1,000 gallons of water!!

 

[Craig58]

I've had my pond for about 10 years now. I remember reading that fish growing to the size of your pond is a myth, but in all these 10 years, I have not had any fish grow to a foot long yet, I think 8 inches or so is the max. size of any of my fish.

Ten years is really good for that number of fish in the pond, especially if the koi are all originals. Your system is doing quite well. Do you do many water changes?

Craig

 

[gardengimp]

Many of you have seen my fountain in the middle of my small pond. Here it is again! Picture from this summer.

The first year the pond was running, the fountain was a self-contained unit. I rebuilt the pond last winter to fix a lot of my original mistakes. The fountain is now connected to the main pond pump. Water flows down the 3 spirals (which have these really cool horizontal ridges) then collects in the basin. The basin is somewhere on the order of 30 - 50 gallons. The basin fills up with water, then trickles over the side back into the pond. It has been running like this now for coming on 9 months.

I filled the basin of the fountain with cabomba and bacopa. Cabomba because I like it but can't keep it in the main pond because it gets 'et up. Bacopa because I just like how it looks in the fountain. Particularly when it is blooming. Here is a closer up look.

I was messing around inside the basin recently. Always have to be doing something in the pond, right? At any rate, I decided I wanted to add some crushed coral on the inner section near the bung hole the water hose comes through. Water also drains slowly out that hole. While poking around in the depths, I realized a few things. First, the basin is entirely full of algae. You don't really see it too much because the bacopa grows up over the top of it all. I clean it out of the top when it starts dripping over the side of the basin, otherwise I let it be. The other thing I realized, is the basin is teaming with millions of little bitty teensy snails. And a lot of micro sized thingies I have no idea of swimming in the water.

My pond is pretty small, and I don't have many fish. I do have this incredibly clear water. I have some mechanical filtration to protect the pump, this fountain and a small bog. That is the extent of my filtration.

I would like to say that I'm genius for installing a vertical stream and a refugium. I have to be honest though and say I'm have just been really, really lucky. Beginner's luck, ya-know.

This winter I am digging out the pond extension. I've been working on ideas for filtration. The pond addition will be connected to this pond by way of the connecting pipe under the sidewalk but the new side will need something. Right now I'm leaning towards a home built skimmer box along the lines of plans I found on waterbugs website, with part of the outflow going into a simple cast concrete basin sitting in the middle of the pond addition and filled with bacopa, pennywort and ultimately algae. (the other part of the outflow would be going into a distribution system on the bottom of the pond)

I'm curious, WB? What are your findings on what percentage to allocate to your refugium? What about depth? In my fountain basin, and in the barrel I have in my veggie garden, I don't see much need for more than about 16". Most of the algae and green stuff is near the surface, not deep. Of course, I'm just guessing - based on what I'm seeing in my yard. But when I think about what I see in the ponds around here, most of the green algae growth is clustered within a few feet of the shoreline where the water is shallow.

When the pond extension is done, I would like to add a half dozen ryukin to the pond. Which of course will be increasing my fish load, so I'm sure I will be needing some additional filtration. Noodling around in my mind and looking around for suitable sized basins.

At any rate, lots of interesting things in this thread. Thanks all,

 

[JohnHuff]

Water changes: I have been very inconsistent with it because I inherited the pond and was really an accidental ponder.
During the growing season: In the beginning, my water changes were very rare, maybe 1-2x per season, and they gradually increased in frequency. The last few years maybe once a month, then once every 3 weeks or so. This season I think there's a leak somewhere and I'm adding water at least once a week. But that could also have been due to my numerous filters, leakage from them or just evaporation from them.
During the rainy season, nature does a lot of water changes for me. Since I live in WA state, I have to drain the rainwater on average 2x a month when it rains.

Size of scrubbers for tanks are actually quite small. For 20g tanks or so, they actually sell very small scrubbers that are magnetically held to the side of the tank and even includes the lights! For a 55g, it's only 7 sq in, which isn't that big.

Algae drying: Ya, they dry very quickly. I keep my pumps on all the time except in very cold weather when I let the pond freeze. The Koi go to the very bottom. Should I sink some kind of container to the bottom for them to hide in, or would it make any difference? They've survived every winter so far.

Question here: Will more nitrogen be removed from the pond if I keep the algae in the pond or if I keep removing it to let new algae grow? Someone commented on that once but I forgot what the answer was.

When algae is the main filtration. The article I linked to mentioned that if algae was the main filtration, not only could there be pH problems but the bacteria that is present is not the bacteria you want.

Refugium: That's what all those Skippies are, with the green stuff growing on top! So I think people keeping Skippies should all have the top open and in the Sunlight. For tanks, I think it's like 20% of the tank size. I have a 29g refugium for my 55g tank, but we've decided to add some fish to that too. Originally, I was going to keep water hyacinth in it, but it doesn't look like the lighting is strong enough.

 

[addy1]

Love that water fountain Gardengimp



addy1, on 09 November 2012 - 05:28 PM, said:

My stream is around 85 feet long, runs about 4-6 hours during the summer, about 2 hours at a time (one a timer) ...

With my stream and rock fountains, if I turn them off for just more than 30 minutes or so, then the algae dries up quick and then just flakes off; don't think they survive it. I don't know, there could be hardier algaes that can survive such envinronments; this would be something interesting to read about indeed.

The stream ponds, small water collection areas, there are many many in the stream, keep any algae alive. That is the only place algae grows in my set up.

If I leave it off for days then the small water collection areas will dry up and the algae will die, but it comes back.