North Wales Koi Club Forum

Following on from the storm I seem to have created on Richdon Forum, I spoke to my source who hates bottom drains and he still stands by what he has said. He thinks its a big gimick and asked me how you would clean one? He said its all about volume and surface area and said a venturi will give better aeration to a larger surface area.
He said there was one shop who started stocking them, then realised they were cr@p and stopped.

Remember, don't shoot the messanger!

Hi Paul,
I wouldn't worry about creating a storm. Koi Keeping is a passion for many people (inc me ) so views are often voiced forcefully

Like I said to you yesterday when your visited, you're 'source' is very much wrong on this occassion. Certain 'gismos' from the koi industry come and go, but Aerated BD's have been around a few years now and wont be disappearing

Cleaning? No ;problem, as the rubber membrane (if it's a proper one) don't degrade and the air flow makes the membrane constantly flex, dislodging any dirt. I occassionally run my Pond Vac over my BD. These membranes were designed for the sewerage industry, so they can handle "Muck"

What creates the improved dissolved O2 levels in the pond water is not the bubbles disolving at the pond base, but the agitation that the air column causes once the bubbles reach the surface (if you want to get technical, it's to do with Diffusion gradients at the water surface). Having Venturis or airstones at the surface has a far less profound effect on O2 levels. The bubbles from Aerated BD's also fetch water up from the pond bottom up infront of them. This creates an additional pull of water/dirt towards the BD. If I turn my Air off, you can see Muck on the bottom, that are only drawn slowly towards the BD. Turn on the air and the muck accelerates on its way to the BD and then the filter

If there is a down side to Aerated BD's it's that your view of the Koi is less good than with no air in the pond (Obvious really ). However, 2 things about this. One; You koi will be healthier, hungrier and happier with the aerated BD, absolutley NO question. Two; Many Koi keepers plug their air pumps into the "Radio controlled" plug sockets available cheaply from ScrewFix & Maplins. As you approach the pond, click the 'fob' on your keyring and the air turns off Click it again once you've fed your koi...and the air goes back on

Just to finish. Venturis are OK, but the creat back pressur on your pump (so it weras out quicker) and Koi damage themselves on the outlet pipe (mine have done this). Airstones at the pond don't force much O2 into the water, and again, can damage koi as they snuffle around at the surface, especially at feeding time.
Hope this helps. Keep asking questions. No one minds a good debate
Martin

Hi Paul,
A koi pond without a BD is IMO not a proper Koi pond, also as I have learnt a DB with an air diffuser is the way to go.
That is why there is one in my garage waiting to go on my new pond build. It is the best way of getting air into the pond. You will not regret fitting one.
Your source I believe used to keep Koi, maybe in the days when DB were new and did not have air diffusers.LOL

Dave.

Hi Paul,

Have to agree with both Dave and Martin, if you don't fit an airated bottom you you will regret it later, its easy to fit now, lot more difficult later.

We built our pond only two years ago and I spent a lot of time researching in all sorts of koi outlets, all the serious one's advised it.

It certainly keeps the bottom clean, I know I can see mine through a window and the fish do love the air.

If you want to see another pond working with one i'm only in Prestatyn, not far from Dave.

Regards,

Ian

Cheers guys, after visiting Martin's pond I took the bottom drain off ebay. It may need some modifying as it has a 1" air intake going to a very narrow tapered pipe maybe 15mm

Hi Paul,
I've made some enquieries at Richdon about the air line and air diffusuer to your BD.

1. The Richdon Air diffuser will screw straight onto your BD (£38). This will give improved aeration and less back pressure on your pump. By the way. In abolutely the worst case scenario you can unscrew this diffuser and replace it when the pond is full.
2. You need to run a solvent welded pressure pipe to the fitting on the BD (about 15mm or 1' as you say). You're going to need to thread 1/2 black air line thru this pipe from you air pump, so make sure that you use 45deg bends, not 90deg. Also, you need a small 'bleed vavle' or tap on the the 15mm/1' pipe, outside of the pond, but below water level. This will allow you to occassionally bleed of the water that collects in the pipe to prevent it getting stangnant and full of anaerobic bacteria.Very simple and cheap to do so don't panic.
Give me a call. I'll tell you something interesting about your BD
Martin