Let me talk about what I meant before I start to answer the questions you asked. At 800 gallons you have a lot of weight in the tank roughly 7,000 lbs. There is fairly little force pushing on the bottom, about 1.5 psi so the ground will not have a problem with that force. But the wood walls will have a lot force against them. You say you are going to use cedar garden post but you don't say how it will be built. So let me tell you how mine is built. I used treated 4x4's for the walls. These were put together like Lincoln logs. On the bottom layer the corners are lap joints so there is a 4x4 going all the way around. Then there is a 4x4 on top of this on the 12' length and then a 4x4 on the 4' width so there is a 3.5" gap between each layer of 4x4 all the way up to the top where the top layer has lap joints. In each corner there is a .5" threaded rod going down through each 4x4 to hold all the 4x4's together. There is also two more .5" threaded rod on each of the long sides holding those together. Then there is 1/2" plywood lining the box with a liner inside that. Within two days after filling the tank the bottom of the long sides had bowed out at least 2 inches in the center. After about a year the long walls on the bottom had bowed about 4 to 5 inches. At that time I decided to put two 2" pipes set in concrete on each of the long sides. This stopped from bowing any more. But even with this there are some pretty good size cracks in the 4x4's after 16 years and at some point the 4x4's will fail. Why 4000 gph flow rate? This gives me a twenty minute dwell time. Is this idea? No one knows for sure but this rate has been used for years with a great deal of success. Filters today are going to a much lower dwell time and they work somewhat. My pond system is 19,500 gallons including the water in the filters. The first 12 years that I ran this filter it had 2 ft of lava rock held above the pipes on the bottom that had holes in them to distribute the water. On top this there was one roll of spring flow and 36,000 ft of 1/2" wide PVC plastic strapping. Then there was 4 inches of polyester pads. This filter was cleaned once during that time. At that point in time I removed the lava rock and replaced it with PVC ribbon which is a machined product of 1/8" wide continuous ribbon. This filter currently has about 18,000 sq ft of surface area to grow bacteria. No I do not spike the biofilter with beneficial bacteria as there is no need to do this. Currently there is no manufacture producing a beneficial bacteria with a bacteria that a good koi pond can't produce on it's own and maintain on its own. Granted it takes the pond years to do this. I have gone on here way too much all ready to continue to talk about beneficial bacteria. Depending on the type of pond beneficial bacteria is not only a good thing but a necessary thing. Mike

The muck is all the algae that was making the water green. Single algae cells clump together, called colonies, to try and protect themselves from UV, normally UV from the sun. That makes them heavier and they sink. This all works very much like dust in the house. A lot settles, some is always suspended. There's no requirement to remove this stuff, but there's no benefit either. In high fish load ponds people don't want it because it consumes O2 as it decays and produces stuff that degrade water quality. A normal Water Garden fish load can handle that no problem and you have a lot of moving water so even less of a problem. People who have a Wildlife Pond like the stuff because insects live in it creating a food chain. That's good for dragonfly and damselfly larvae. The downside is how it looks. Longer term, as it decays it becomes smaller and smaller bits and at a certain size it's called DOC (dissolved organic carbon/compounds). The reason a name is given to that size is because it acts differently, acts like soap, can create foam on the water surface. As it continues to decay it gets even smaller (we're talking the size of bacteria) and it stops being a DOC. Another issue is as it decays it becomes lighter and over time (like a year or two) it starts to not settle back down and becomes suspended. Looks like pale ground pepper suspended in the water. That makes the water less clear, and just generally dirty. There are filters that can deal with that but it a bit tricky. There was a time when I just let it be. But I changed to removing it and keeping the pond clean. Just made keeping the pond easier, water clearer. It can be removed with a fine net, like those green minnow nets from the pet store. You have to scoop very slow. I use a vacuum I make that I call a Silt Vac In a small pond the net works very good. Your size pond is kind of in the middle, kind of too big for a net, kind of small for a vacuum. But the Silt Vac can certainly be scaled down and a smaller pump used. I also have a web page that compares the different kinds of vacuums. Really important to pick the right vac for the pond size and also what you're removing. For this fine stuff you need a vac that removes water. Trying to filter the water to return it is a real waste of time...tried many ways. Loose gravel makes vacuuming difficult. You can put a valve on the pump to reduce power and try to get the sweet spot where there's not enough power to lift gravel, but that slows you down too. I like rocks on the bottom but I like them mortared. That makes vacuuming really easy, even better than bare liner because no wrinkles and the rocks look nice when clean so it's a reward where seeing bare liner isn't so nice imo. If you do decide to vacuum it's nice to have a place to hook the hose to so you don't have to have a separate pump. This is how swimming pools are built, the skimmer has an intake that is sized for the hoses and the pump just sucks the hose into place. Very easy. Unlike a swimming pool though you need valve(s) so the pump exit goes into the yard. I used a separate pump because I cleaned other peoples ponds. This settling stuff will normally be on on going thing, just like dust in the house. There are ways to direct pump output to the bottom to keep the stuff from settling so filters can remove it. But that is more complex than it sounds. Your filter for example will remove some of this stuff but probably only maybe 10-20%. There are other filters that remove more. It's a whole deal.

lesliew I have a pond that is about the same size as yours. I have a gravity filter that keeps my pond clear all year round. This filter is outside of the pond and it looks like a large utility tub. I have it sitting right next to my pond so I put a small fence in front of it to cover the front of it. This is how my system is set up: my water comes in from a garden size hose into a tube that is about 5 in diamiter ( I have a rock that holds the hose in place). The water then falls into the very bottom of the filter in comes up through a small grate,furnace filter, lava rock in bags, then roots of iris, water celery, anacharis, horn wort and out a 3 in tube that feeds back into the pond. I have a bottom drain that allows me to clean this filter out every spring. When I clean it in the spring I take out all the iris, chop them to pieces and give to any fellow ponder that will take them, hang on to a clump about 6 in in diamiter. throw away all water celery, it comes back anyway, replace lava rock. I buy the landscaping type just make sure you rinse them throughally before you put them in. Buy a new furnace filter at hd they are about 5.00 and worth every penny. The grate sits up about 4-5 in off the bottom so that allows all the fish poop and rotted stuff to settle in that area. When you go to clean out the filter you will want to save this sludge...it is black gold, my plants love it in the spring its like a energy drink for them. Once you put it back together you are done until next year. I do have to clean my pump about every 4-5 weeks but that is easy and takes about 10 min. I have pictures of my filter all taken apart that I can mail to you, they were not done on a dig camera, just let me know.

Ok - here's a quote for YORK equipment... Any comments on York Affinity vs Carrier Infinity vs Trane? York and Trane proposals are 80KBTUh/60KBTUh (main/attic). Carrier is 66KBTUh for both systems. Any thoughts? ***Company #3 (York Dealer) - $13.9K (rebates included) 2 year labor 10 year parts Lifetime compressor Heat exchanger warranty not stated New pads Zone 1 (Main Level + Basement) York Affinity (modulating, 80% AFUE, 80,000 BTUh Input) YPLC080A12MP12 York Affinity (3 ton, 15.75 SEER, single stage) CZF036 FC43B York Communicating touch screen programmable T-stat Flush existing lineset Additional filter grill return in basement YM10PAC1625 media air cleaner Zone 2 (Upper Level) York Affinity (modulating, 80% AFUE, 60,000 BTUh Input) YPLC060A12MP12 York Affinity (2 ton, 16.5 SEER, single stage) CZF024 MC37A York Communicating touch screen programmable T-stat Flush existing lineset Additional filter grill return in master bedroom Option to go to CZH036/CZH024 (2 stage 17.75/16.75 SEER) for add'l $200 each ($14.3K instead of $13.9K)