[natural12]

Hi everyone. This is my first post. I have been enjoying reading many of the posts and I am impressed with the high level of knowledge here.

My situation is we are going to be constructing a koi pond for a client. The client requested the use of bottom drains. Does anyone know where I can buy some quality bottom drains? I have not installed one for a long time. The ones I have installed I placed on top of the liner and ran the plumbing up and over the liner - hiding it as best I could. I really need to avoid that for this project and would like to install it much like a swimming pool.

The reason for my concern is back in the 90's I worked for a company that installed a lot of bottom drains and we had a fair number of problems with them leaking after a number of years. I hate a leaking pond.

I buy most of my stuff from Anjon and what they have for a bottom drain looks pretty cheap.

Any suggestions would be appreciated.

Thanks,
Mike

[Dire Wolf]

Over the past 18 years I have found most Koi pond owners really want an outdoor fish tank. We did one of those 7 years ago and it was the last. Nothing but trouble.

Look up the aquascapes system the principle is biological and not having more fish than the pond can sustain. The bottom drain is nothing more than a toilet bowl that will leak. BTW 1" of fish for every 10" of surface pond. convince your client to do withou this.

[natural12]

Basically my concern about the bottom drain. Leaking. I have probably done about 40 ponds over the years so I feel I have a strong understanding on how to construct one and various filtration systems one could use. I prefer keeping it simple with a skimmer filter and some kind of bog/biofilter area.
Early in my career I worked for a company and we used all sorts of filters such as settling tanks and bead filters with external pumps. There was always some kind of issue.

Anyway, I try to give the customer what they want. So if I can install a quality bottom drain and feel confident with it I would prefer that route. They already own koi fish so there is no convincing them otherwise. They are located in a pond in their old house.

MIke

[natural12]

I grew up not to far from you in Miller Place.

[ianc]

could you not run a pipe from the pond bottom (insider the liner)to just below the mouth of the bio-filter and use the constant draw and intake the bio-filter pump delivers to provide some suction and lift the fish waste

I use the Savio filter boxes with the Bottom Draw knock out
the fact about cutting the liner to run the pipe from inside the liner
outside to the side of the skimmer box - they ALWAYS LEAK

[natural12]

That is an interesting idea. So bring the pipe up to the mouth of the skimmer opening? I also use the savio skimmer filter and like them.
I am not sure that would pull much if any water up the plumbing. Maybe I am not understanding you. I would just bring the pipe up and over the liner and use a knockout like you described but this is kind of a raised pond so the top of the pond will have a stone coping. Want to keep things neat.
So have you had problems with leaking bottom drains?

[ianc]

it definatly creates a draw - I have done this numerous times with mixed sucess - the sucessfull ones have an oversized pump
and if you angle the top cut on the pipe and get her close to the skimmer mouth but still under the desired water level there is a draw - how efficiant it is to lift the fish waste - it does however circulate + exchange the bottom water

[PSUscaper]

What is the purpose of the bottom drain? Is it for circulation reason or is to drain the pond easier so it can be cleaned.

If it is for the second, tell them to buy a cheap $80 sump pump and drain it that way when needed.

I'm with everyone else. A bottom drain in a liner seems destined to become a leak.

[Fine Edge]

We used to install above-ground pools & liner changes years ago when planting was slow in the Summer. Putting a bottom drain in has the same principle as hooking up your pond skimmer to the liner. Just use a gasket under and over the liner ( gasket adhesive is not mandatory but would ease your mind ), a top plate & the grate. Try a pool supply store and see if they have any sizes that fit your needs. The draw from the bottom drain can be regulated with a ball valve and can also be T'd off with another ball valve to drain the pond if needed.
We have used this exact assembly before and haven't had any leaks.
All liner pools with deep ends should have main bottom drains.
Why wouldn't this work for a koi pond?
Plus, I have seen beautiful koi ponds & if that's what the client wants, why not give it to them? Just tell them that they need to educate themselves on the proper maintenance.

[Dire Wolf]

The purpose of a bottom drain is to remove solid fish waste into a seperate vessel by way of a 2 1/2 inch Knife valve plumbed with PVC. The theory is you may remove waste and do a water change without disrupting the salinaty and PH of the entire pond. in a Koi pond ph is maintained at neutral and salt is added to prevent disease and enhance the coloration of fish.

Be sure to not only use bulkhead gaskets inside and out but also use silicone made for epdm liners to ensure tight seal. BTW Natural 12 I grew up in Sound Beach.

[natural12]

Fine edge - I think I will check out some swimming pool suppliers. Good idea.
I think why some bottom drains have failed in the past is the plastic product and the sealant degraded. Probably due to exposure to all the muck and stuff. Plus the products seemed to be low quality.

I think if I use a quality bottom drain I should have no problem installing it under the liner.

Dire - thanks for the info on the bulk head fittings. I have used them in the past. I will use them for tapping into the skimmer. Did you go the MPHS? I graduated in 83. Getting old.