Basics of a Bottom Drain

[malatu]

Could someone give me a quick lesson on "bottom drains". Are they just what the title implies .... simply a drain that discharges water out of the pond or is it part of the filtration system or both? Or can it be either of the two.

 

[koidaddy]

It is a filtration means to keep the bottom clean. Be carefull if you install one as they are a leak waiting to happen if you cut your liner. I made one from a 8" roung pvc floor drain that is just plumbed into the pund with 1 1/2" pvc rum with a pondmaster md24 pump. It sits almost on the bottom.

 

[malatu]

It is a filtration means to keep the bottom clean. Be carefull if you install one as they are a leak waiting to happen if you cut your liner. I made one from a 8" roung pvc floor drain that is just plumbed into the pund with 1 1/2" pvc rum with a pondmaster md24 pump. It sits almost on the bottom.

If I understand you correctly, your bottom drain does not penetrate your liner.

 

[koikeepr]

let me offer a different perspective. If properly installed, a bottom drain will not leak. And, yes, a bottom drain serves to get debris to your filters.

There are two types of bottom drains, one is a vacuum (or retro drain), such as this one by aqua art that sits on top of your liner. I personally own this drain on my old pond and it has worked spendidly well. You simply plumb it through a side wall on your pond or some people can go up and over the edge of the pond. Keeps the pond floor nice and tidy. You can use this type with a submersible or external pump.

A second type is a traditional bottom drain, such as this one. They are typically 3 or 4 inches and can have aeration or not, and these go through the liner on the pond floor. You can see how they are installed in my other thread of building a 5,000 gallon pond. I just put two 3" aerated drains in my pond build. These are really made for external pumps.

Bottom drains help clear out the crud at the bottom of the pond and move it to filters so you can get it out easily. With a BD, you basically have a very clearn pond floor.

Now, let it be said that you don't need a BD. Lots of folks on this site do plenty fine without one and they keep up a meticulously clean pond by keeping up with it. My pond did not have a BD when I inherited it, but once I installed the retro one, it made a huge difference in maintenance for me and I never had to use a pond vac or clean the bottom of the pond again.

So, for me, BD's make sense and I would say that you should not be scared off by people claiming leaks. Again, like any other piece of pond equipment, if it is installed properly (and it certainly isn't rocket science), you will not have a problem.

That's the beauty of ponding--you can do what works for you.

 

[koidaddy]

If I understand you correctly, your bottom drain does not penetrate your liner.

Exactly. The pump sits on a shelf about 8" deep and is connected to a 5' piece of 1 1/2" pvc that is angled slightly down toward the bottom. I also drilled some 3/8" holes at the bottom of the 1 1/2" pvc maybe 12. about a foot up so to keep any fish from possibly getting stuck from all the force from the bottom pickup. I used to have smaller 2 inch drains but just found the 8" one.
When I had the 2" I lost a baby or two by getting stuck untill I added the extra drilled baffles.

We have sand here and the ground will shift some. If your ground is harder it could be done.

It is not noticable once painted flat black.

 

[koidaddy]

Koikeepr, here in Florida we have sand all the way to the water table. That is why we don't put them through the liners. The sand moves to much. If I built a concrete pond I will deffenitally incorporate bottom drains in to help keep cleen. I guess it comes down to how big the pond is.

 

[malatu]

Excellent information guys, I appreciate it! With all that said, my pond will be installed in 100% sand. The location of the pond will be sitting over a large in ground pool that was filled in 12 years ago by previous owner. The pool walls were knocked down and placed into the pool's bottom (the bottom was earth with a liner on top) which was then back-filled with sand, I've had absolutely 0% settling since I moved into the home 10 years ago.

Would my situation be a "less than desirable" candidate for a "through the liner" bottom drain?

 

[koidaddy]

How deep are you going to make it?

Also it does have to settle much to pull a rubber and put pressure at the bulkhead.

I am just paranoid about loosing water myself.

 

[koidaddy]

How deep is the sand? You have solid dirt under that so that helps.

 

[malatu]

How deep is the sand? You have solid dirt under that so that helps.

Hmmmm.... It was a fairly large in ground pool. The shallow end was approx. 2 12" the deep end was probably 8'. The pond will be over both the 2' and the 8' section, but mostly the 2' section.

My pond will be a max 3-4' deep. It will be irregular shaped approximately a minimum of 11' x 20'.

 

[koidaddy]

Well at that size I would ultilize some sort of bottom drain. I am not a fan a cutting the liner but it can be done and with little problems i'm sure. Where theres a will theres a way.

 

[malatu]

Ok .... sorry for the basic question ...... but as I look at the bottom drains, some are aerated and some are not. It appears the aerated is better. Why? I'd be interested in the science that allows it to do a better job of keeping the pond cleaner than an non aerated bottom drain. Also, I assume the larger pipe intakes water while the other delivers air to the pond. What is producing/moving the air?

 

[malatu]

Just answered my own question. Here is a link to an informative article on the benefits of bottom drains.

http://www.exoticwaterscapes.com/drain.php

... and thanks again for all of the great and "timely" information! I appreciate it!

 

[DoDad]

Aeration ads oxygen to the water, tends to keep bush surface debris towards the skimmer and causes a current that pushes bottom debris toward the bottom drain.

 

[malatu]

Thank ya much!