Question about attached plumbing diagram

[Craig Brown]

In the attached diagram, what is a "cleanout valve"?
Speaking of valves, as I build my plumbing I would like to include a few valves and unions (to make changing parts easy). For 3" PVC there are options such as ball valves and gate valves. Though gate valves are cheaper, I read that they can fail when water pressure is high. Should only ball valves be used?

Thanks!

 

[mgmine]

First off I would go with no larger than 2" pipe. The parts are cheaper the smaller the pipe. Use what ever size your pump requires. Don't worry about the pressure on the valves there isn't that much with a pump used in a pond. I would put the pump and the check valve in the skimmer for several reasons.(1) If the pump develops a leak it won't pump the pond dry.(2) It will be out of sight and (3)a water pump pushes better than it pulls. I wouldn't use a bottom drain. You're not building a swimming pool and the more cuts in the liner mean more places that can leak. I don't see any reason for clean out valve where it is placed unless of course it's to run a snake through to clean out the useless bottom drain. If there was one needed it would be on the filter and it would be used to back wash the filter to get the sediment out. If the pump is placed in the skimmer then the only place unions would be needed would be for the UV light. Speaking of the UV light it should have a loop on it so that you can regulate the speed of the water going through it. The way it is plumbed now if you slow the water down then you are slowing your out put down. Have you considered building a skippy filter? Last but not least why have two returns going back to the pond? One is enough and it can go to a water falls.

 

[Craig Brown]

Sorry, I was not clear. This is not a diagram of my pond.I was looking at a web site that had this diagram and I did not know if the term "clean out valve" was a standard valve used in ponds or just words that meant something else.
I've got a good bottom drain, and the engineering of the way it attached to the lining makes it unlikely it will develop a leak. The possibility is > 0, but I am reducing it further with my own technique.

My pond is about 30% underground and on a slant. A bigger concern was that the pressure treated wood would rot in 10-15 years. As a precaution, I covered the entire structure with roofing tar. It was a messy job (though it looks cool in shiny black)! Eventually it will be covered by stone.

 

[mgmine]

Okay if you already have put the drain in then it's too late to reconsider. Many years ago I used to work for a swimming pool company. At least three times a season we would get called in to repair the bottom drain. Not the drain itself but the pipe running to it would leak. What happens is the water seeks it's own level and you cant cap the bottom drain. So when the ground freezes the pipe would freeze and crack. To fix it we would run a smaller size pipe through the existing pipe and seal it in the drain. If you put the clean out in it be sure to use a sanitary wye and not a tee. Face the slope towards the pond.

 

[Craig Brown]

Thanks for the response! I was going to put a straight pipe from the drain; under the pond to a point about a foot from the pond (total of about 8'). I was then going to put on a Tee. At each opening there would be a valve. One would lead to the filtration system. One would be for drainage (pool cleaning, etc. Really "just in case). The drainage pipe would never be opened so the Tee should not effect water flow. Does this make sense?

 

[mgmine]

Instead of a tee use a sanitary wye. I'm not clear on what the settling tank is for.

 

[Dave 54]

Are you in danger of making things just that bit complicated . I have a pipe that is connected to our four filters and runs off to sewer from them [not mid pipe where things can go wrong] especially if you either make a mistake or spring a leak to sewer[thats your pond totally gone Craig], what happenms if you dont notice this mistake and go on holiday because even a small leak can empty a pond .
One thing you must remind ourself my friend that water always wants to escape , that's a lesson learned the hard way
Dont say you wont make a mistake because shit happens, we have all made them oursleves included .
Take the too sewer out and instead trun to sewer from your filter.
We did it with both including our overflow/skimmer dont say we didnt warn you if you ignore this.

Dave

 

[Craig Brown]

Thanks!
Please note that I don't know the correct words for things. In my diagram (where it says sewer), it actually is not connected to anything. We are not allowed to tie in with the sewer system. It would just drain out into my yard (instead of using a sump pump to drain). "Settling tank" I meant the first filter tank. I guess you call this a pre-filter. That would be connected to a (commercial, purchased ) pond filter. A pump attaches to that.


Alternately, I spoke with a local pond installer (old timer ... not that I'm one to talk He sells a skimmer that has two chambers. He says he has had a lot of success by modifying the second chamber to attach to a bottom drain (he does this for free, since you are buying from him vs. getting it cheaper online). His ponds go into the homes of wealthy people (saw photos, beautiful stuff) so he tends to recommend the most reliable parts (vs. lower price so he doesn't have to fix them).

Thanks again!