Wow! Excellent explanation PP. And such a quick response too. Thanks.
If you don’t mind I’ll post my set up in the introduction thread I already have started, just to keep things more organized.
You mentioned your main concern was about your bottom drain freezing at the knife valve. That’s kind of funny because that is the main area in my system I am concerned about and kind of why I was asking about your system, to see if you had any extra insight into the mater.
In my case I have one big difference in my system that I think (hope) will make things a lot safer for me, and that is that my bottom drain exits into a very well insulated pump house room. I spent a good chunk of change building this indoor filter/pump room, so I’m hoping it will pay off by eliminating any chance of that line freezing, but never say never, right?
I’m in the same boat as you with respects to just getting the pond up and running in time to shut it down for the winter, so I, like you, will be watching things pretty closely.
One issue that appears to have already come up, that may also effect you is these knife valves, or gate valves as they are sometimes called. They may not all be the same, but when I bought mine the irrigation guy warned me that they don’t take pressure very well. I explained it was only going to be used in a gravity feed flow system, and that the pump would be located after the gate valves ( I have a few valves in my system). Anyway, I drained my pond half way after the initial fill so I could do some rock work. When refilling the system I shut off the main bottom drain gate valve , so I could just fill the pond without filling the filter barrels, but when checking the fill rates I noticed the filter barrels were still filling up slowly. The only explaination I can come up with was the imbalance in pressure between the pond water depth and the barrel water depth was enough to allow water to seep through the knife valve.
Again, I don’t know if all these knife/gate valves are the same, or if you have ever tried completely draining your filter barrels yet since you filled your pond, but it could be a problem for you. Especially because I notice it looks like your valve is down well below the top of your water level, maybe even lower than mine. I hope for you sake that it’s not a potential problem.
I’ll see what I can put together over on my thread (Getting back into water gardening) to describing my system. I’m kind of doing things in slow motion right now though. I'm actually recuperating from hurting my back, I did a bunch of rock work in the pond over the last few days and then went and cut and load of firewood yesterday. Today my back is rebelling, I can’t stand up straight and can hardly walk. I guess it’s my back’s way of telling me it needs a few days off.
