Bumping this down. Brenda

Waterbug guy, First I will talk a little bit about concrete in water. You say it is a myth that concrete in water can kill fish and raise the PH. When concrete first sets up the surface PH is 12.0. Which is the same PH as a drain cleaner called "draino". As it is exposed to the CO2 in the air the PH goes down. But water is a very good leaching agent and so water will continue to try and get the chemicals out of the concrete. So will the PH in the water be raised? If the water has normal PH of 6.5 to 8.5 the answer is yes. The real question should be "how much will it raise it"? That question isn't easily answered as there are a lot of variables. Just to list some the age of the concrete, the condition of the concrete, is the water flowing over the concrete, the natural PH of the water, is the water being changed, and the volume of the water versus the contact area of the concrete. In some cases the rise might be so low as to make it very difficult to measure. But in other cases it can and does raise the PH to 9 to 9.5. At these levels it can and does kill fish. If I remember correctly you have stated that you are a pond contractor. If you are I hope you having started using roofing liner in the ponds that you build. Most of the time a person on this forum is never going to have a problem with roofing liner. Can there be a problem with roofing liner? This should be the question. The answer is yes. The chances that there could be a problem is very low. The largest pond product manufacturer in the US sent out a letter to all their customers a number of years ago. This letter said that all their liner in the future would be tested to be fish safe as they got a batch in that was not. In other words they were selling roofing liner as pond liner. This company had been selling a lot of liner for 10 years before this problem. If it had happen today with the wide use of the internet I would have think that some lawyer would have gotten this information and started a class action lawsuit against them and they would be out of business. The lawyer could easily have sued them not only for the cost of the liner that they had sold but for the cost to replace all those liners in the ponds built with them going back to the first time they sold this liner. The largest liner manufacturer in this country has told me that almost never would you ever have a problem with roofing liner but you might. I think that as a contractor you can't take that chance. If you were unlucky and did have a problem and were sued over that problem the lawyer handling the case would find out that they would sue for every customer that you have that has this liner. In other words you would be out of business. So is roofing liner toxic? No most of the time. But there is a small chance that there maybe a problem. I have only talked about 2 of the 8 things that you listed. I could easily talk about many of the other things listed but my point is this. You listed these things as black and white but they are not black and white. The only thing that is black and white about ponds is that all aquatic life will die. Mike

I started with a small pond about your size. I learned a lot before I decided to use it as a skimming pond for a 14'x16' pond 2' deep with Koi and goldfish. The algae is a normal process the pond will go through and will eventually get better as the pond matures. The UV filter should get rid of it. I suspect your bulb has lost it's power or not working. Change bulbs and be sure never to run the light when the water is not flowing through it. Other algae will come later that the UV can't kill. My biggest problem was and is string algae that the UV will not take care of. It will clear water nicely and fish will eat it, but is an eye sore to look at. I used barley straw to keep it from getting worse but it will not kill it. The only thing that will is scrubbing with Peroxide. As barley straw decomposes it creates a small amount of peroxide. You should keep it in the surface near a flow of water. But you will need to scrub down your waterfall, filter, etc., to get rid of it. Eventually the string algae disappeared as the pond matured over a few years. I still use a UV light but it is not needed as much as it did when the pond was immature. Anyway... Replace your UV bulb and it should eliminate your algae.

Marti8a, Thanks. We did a little on line research and we know what to expect in the way of eqp ... luckily there is an easy out of the way place to site it. Not sure if we have local pond tours ... garden tours, yes. KMarcel, Glad to hear you enjoy them. We are planning on 4' minimum, and a bottom drain. I want the little fellas happy! Annie, Those are cool. But I think we need something with visual weight to anchor a 17' wide circle ... these are so delicate. Cloudswift, It sounds delightful to have koi. I am not sure about hiding places vs cleanliness. Some things I read advise to keep the bottom clean and empty, it seems... Good news about straight sides. Ours would be straight, since a slope would look odd within the stone circle IMHO. One thing DH said is that any heron that is on our property would have two choices. 1) An almost 2 acre pond with carp, bass, sunfish, frogs, snakes and (as of their delivery 2 hours ago) a seasonal supply of 200 trout, 100 feet from our house. Or, a 17' wide pond only ten feet from our house with a few koi in it. Hopefully they don't have a taste for koi! KSWL, I see your point. And I do try to keep to the vernacular, although some elements ... indoor pools, flat screen TVs, etc are hard to make "ye olde"! I think the issue here is that you will only see them when you want to. They are off to the side entrance. Most of the time, it will just read as a fountain, which is why the fountain cannot be asian, modern, or italianate. Lazy, That is very sweet and kind of you to post again to press your point! From my breakfast room banquette, I would probably only see a small trunk of a new tree (given the roofline and the windows). I would like to create a reason for people to go to this overlooked patio area. I need a draw. A tree won't be.