I also remember you mammabird. I usually don't use the forum much in the winter but come back on in the spring just to catch up on what's new etc. I have a retrofit bd as well mine is some modifications on the Tetra through the liner drain (which froze) but I used the cap from it for my drain. I am replacing that this year with the Aqua Art Drain as it sits flatter than mine. Not sure if I understand your "hump" but you usually put the bd in the deepest part of the pond. Avid koi-keepers like to do TPR's--but that also means cutting a hole in the liner. With your pond dimensions you might want two bottom drains one for each deep section. That would mean two bulk heads (I did pipe boot connections) through the liner on the side of the pond wall nearest your settling chamber. My drain has a 4" line reduced to 3" just before it enters the sc followed by a 3" knife valve (there much cheaper!). I take my drain out for winter because of my climate. Water inside pipes in my climate not a good idea. My settling chamber is a liner chamber (kinda like a pond beside the pond)350 gals-my pond is 2500 gals. They say sc should hold at least 10% of your pond volume. I really like this system as use sc for water changes. I have 3-4 ft square matala mats in my chamber which is also my mechanical filitration. Good luck with your new pond and move. Patti

There are many ways to run a pond, each person has to decide for themselves. The dirt in the water is a tough one because it depends on the kind of dirt. Some will settle right away, some will stay cloudy for a long time. It will most likely settle at some point in the future. Tomorrow, next week, next year, no way to tell. There is also the question of what "clear" means to you. What one person considers clear another person would not. If it were me, unless water was being rationed or really expensive I'd dump the water and start over. You will have plenty of other issues, no sense adding to that list. Chalk it up to learning. I don't think there would be any problem adding fish to a pond that's cloudy from dirt. There's a small issue of the fish getting grit in their gills, but I think that concern is way over hyped. Grit settles. What stays suspended is clay and Koi live in mud ponds all the time. There are endless products being sold to clear the water. All are scams. Some actually could work, like flocculants. These are used in waste treatment plants. But in order to truely work 3 steps are needed. 1. Pour in the flocculant. 2. Apply extreme agitation to get the bits to clump into large enough clumps for the next step. 3. Removal of clumps using a fairly sophisticated filter. Pond flocculant products being sold don't talk about steps 2 & 3 of course. So people buy the product, which is the only step the seller really cares about, pour it in and it often makes things worst or if the pond does clear it's only temporary because the polymers in flocculants break down pretty fast and the clumped dirt goes back to being dirt. Virtually all pond products work that way. Part truth with a lot of scam. Sellers don't worry about repeat business because only people new to ponds buy these products. "Benefical bacteria" same deal. Most are completely worthless. There are a few that may sometimes contain some actual benefical bacteria and in a few cases can help. For example say you were about to add 20 full grown Koi to your 2100 gal pond. In that case you'd expect ammonia problems right away so trying to get bacteria working fast would save you some work in the next couple of weeks. But if you're like most people you're going to add a small number of very small fish which won't create an ammonia problem. You already have benefical bacteria in your pond, they're everywhere. They reproduce to fit the environment. Right now there's almost no ammonia for them to eat, so they just sit around watching Oprah all day. As soon as there's more ammonia they start eating and reproducing. Adding more bacteria to a pond that doesn't have the food (ammonia) available does nothing but add waste to the pond. If you really want to create more bacteria before adding fish you can do that by adding ammonia, plain ammonia from the drug store, to your pond. Use your ammonia test kit to get it up to some reasonable level, say 2ppm. Then use your test kit to to measure ammonia dropping, and maybe nitrite climbing and then falling. Takes about a week for the ammonia to go, nitrite can take longer if you measure any. Ammonia is also a food for algae so doing this really requires a UV filter to stop algae from sucking up all the ammonia as fast as you can put it in. Or, just add a few small fish at a time and let them produce the ammonia for the bacteria. Simple as pie. Local pond store guys are the worst pond keepers on the planet. They have to be. Water Gardens are very easy to run and require almost nothing be added. No pond store could stay in business based on that. So they make a living selling stuff no one needs. I have seen a few good pond stores that made most of their money selling good quality Koi and useful products like liner and high end filters. But those are rare. Adding salt to a pond is done by some people, not a lot. Whether it's a benefit is inconclusive in my book. The biggest problem I have with it is what do you do with waste water. Dump it on your lawn? Over time that probably isn't going to be good. Most cities have laws against sending down a storm drain or sewer. With no clear benefit I say who needs the hassle. And it takes a lot of salt to raise a 2100 gal pond to a level that matters. I'm guessing the pond guy sold you like a few pounds of sea salt flown in from the Black Sea or something. Regular water softer salt from the hardware store is all that's needed if you chose to go that route. $5 for a 40 lb bag. I'm guessing the pond store guy's salt costs a lot more. Salt is salt.

If you are planning a liner pond there is little concern with the concrete cracking around the BD. The liner seals to the BD, the concrete is only there to stabilize the BD. The deeper you can make your pond the better for koi, particularly in a cold climate. It helps moderate the temperature and also gives the koi vertical space to swim. In my case I chose to go 7' deep and to bury all the pipes. My pumps and skimmer are in an insulated below ground vault through which all the pipes pass and in which are all the necessary and convenience valves. I shut off one pump for winter but leave the skimmer running through the biofilter and back to the pond through multiple gravity returns. I use floating pool covers to help insulate in winter and depend on the open water in the running skimmer to serve as an open area for gas exchange. Better would be a frame and suspended cover, a greenhouse. You can design a pond in zone 4 to keep koi year-round, it just takes a little extra thought. There are a number of koi-related internet sites, including this one, you may wish to consult while doing so. Besides Gardenweb, I found one in particular to be invaluable - perhaps you've found it by now? Conflicting recommendations are the norm, it makes things confusing. If one spends dozens of hours reading construction and maintenance posts on these forums one eventually learns who to trust and what might work for your particular situation. This is only my 3rd year with artificial ponds, there is more sage advice out there.

Yes, I agree with the liner. I would reccommend a Koi specialist come in and transfer the Koi to an oxygenated invironment while the pond is drained and the liner can be installed. Put in some new air stones with an aerator. If it does not have a UV filter, I would reccommend one of those as well. Roots are OK for decoration as long as they are bleached by the sun until dry and gradually introduced into the invironment.