I'm running a waterfall - so do I need air?

Mattsville · 12-08-2011, 11:59 AM

Hi,

From what I've read on here it sounds like having an aerated pond is now considered pretty much compulsory. Is that right?
My Dad has a pond and has never had air going in, and the koi never looked like they were struggling for oxygen. He does keep quite a few plants in there though, and it's fairly sparsely stocked.

I'm planning on running approx 2000 gals with a waterfall - and for the first year will have no more than 60 inches of koi (6-8 small koi) - so I'm pretty sure air won't be needed at first. Will it definitely be needed by the time the koi are more like 150 inches in total, or will the waterfall be enough? I plan on running about 800gals/hour over the waterfall. What would provide more oxygen - a diffuser with about 50l/min air going through it or a waterfall with 800 gals/hour going over it?

Thanks,
Matt

pondy · 12-08-2011, 02:20 PM

will the waterfall be running 365 days of the year?

Mattsville · 12-08-2011, 02:54 PM

Hi Pondy,

I think that will depend on how cold it gets. But it will certainly only be off in winter, if at all. As I'm not heating the pond I won't be feeding much in winter, and as koi don't move about much then and cold water holds more oxygen than warm then I wouldn't have thought that would be a problem?

Can koi be "fine" with a certain level of oxygen, but healthier/happier/grow faster etc with more oxygen? Or is it that they either have enough or they don't?

Doghouse Riley · 12-08-2011, 03:33 PM

I'd been running a 3000 gall pool system with a waterfall and a return that splashes water in the pool, probably a participation 20/80% for many years.
So certainly some air was being forced into the water.

I don't think the pool has ever been short of oxygen as the fish I had in all this time never showed any symptoms of any oxygen deprivation.

But I recently added an Oase AquaOxy 1000 and within a day they were far more active and have increased their food consumption and have since shown impressive growth.

So I guess in such circumstances it's just a matter of personal choice.

Mattsville · 12-08-2011, 03:52 PM

Oh, that's interesting!
So you reckon they were fine before - but it definitely made a difference adding the air?
OK well that's pretty much made my mind up then - I'll fit an aerated BD and get a pump for it as soon as I have more than a couple of fish.

The drains I've been looking at have 1 inch dedicated air line fittings. My pond will be about 6 ft deep at the drain. I'm thinking that if i turn the air off and the air pipe fills with water then that's a lot of water for a small air pump to shift at that depth? Would I be better just using an 8mm air line and somehow attaching that to the 1 inch fitting on the drain?

freddy · 12-08-2011, 04:22 PM

Hi Mattsville.

I've recently more or less finished my pond build which is pretty much the same as you are proposing to build. My bottom drain is a Spindrifter which is the same as you describe. I use a Hiblow 80 to run it, using the 1" pipework. The blower has no trouble pushing out the water. One added benefit of using this type of bottom drain with the airdome, is that when it's running, all the crap gets drawn towards the drain. Personally, I wouldn't rely on a waterfall supplying enough oxygen. It would probably be ok for now, but somewhere down the line you may well regret it. Hope this helps.

Cheers...Freddy.

Doghouse Riley · 12-08-2011, 04:32 PM

I was quite surprised the difference the air made to the activity and appetite of the fish.

I can't advise you about supplying air to a bottom drain.

I'm "old school." My bottom drain is connected to a 40 gallon pump sump with a 4" socket in the bottom for a standpipe.
The pump is positioned near the top of the sump.
The water coming up from the drain always looks reasonably clear of debris, but a purge brings all manner of stuff up, which with a second pump I can pump to waste.
I purge the drain twice a week in the summer.

I have the air stones on the ends of the lines supplied, they hang down near the bottom of the pool below where the water returns so the bubbles get distributed by the incoming water.

I'm very impressed with my pump, (but then I was with an Oase 5000 filter pump I'd had running 24/7 for ten years, which I changed for an 8500 early in the year as I wanted to increase the flow of the waterfall, I'm keeping the smaller one as an emergency spare).

The air pump came with 10mtrs of hose, two air stones and two spare diaphragms.
I bought a new one, but one a month old came up on eBay a week later and went for £51.

Davej · 12-08-2011, 09:54 PM

Hiya

In reality 800 gallons per hour isn't really much of a waterfall, it would help, but much would depend on how high the fall was.

Building in some form of aeration into the system at build stage has to be a good idea, so much neater.. Agree with Freddy and run the 1" pipe back to the pump, it will minimise back pressure on the pump, a half decent 40L pump will do the job.

Dave

freddy · 14-08-2011, 08:56 AM

Quote:

Originally Posted by Davej

a half decent 40L pump will do the job.

Dave

Hi Dave.

As I said, I use a Hiblow 80. Would you say I have too much air going in? (5ft deep, 2,200 gals)

Cheers...Freddy.

Davej · 14-08-2011, 10:18 AM

Hiya Freddy

I wouldn't think so Feddy, think its a question of how and where you deliver the air.

Ive found that 40L to the BD creates as good an extra draw as 80L, in giving the pond a clean bottom.

In terms of getting more oxygen into the water all depends on the water

, but my take is that surface aeration is more efective than that delivered deep down. So theres possibly a balance.

Personally Ive moved (had to move) away from air being delivered into the pond as I get all I want from 15,000+ gallons an hour dropping a meter or so over the showers.

Dave