I have a client who is presently landscaping a very large property on the west coast. I was contracted to supply and install water lilies in the above pond in December 2008. This pond is huge, and holds approximately sixty thousand gallons of water. As a rule before putting plants into ponds we check the pH of the water. A very low or high pH and I mean above 9 or below 6.5 is toxic to water lilies and fish, so it is important to bring it down/up to acceptable levels between 7.5 to 8.5. The pH of this pond was very high, this is typical of newly unpainted concrete ponds. Concrete leaches lime that makes the water alkaline, pH readings indicate the alkalinity or acidity of the water. Concrete ponds are usually sealed when plastering with water proofers and sealers mixed into the motar, however they do leach initially. One way of avoiding this problem is to paint the finished pond with a rubberized paint or any pond sealers that are available. We treated it for several weeks before the water lilies were installed. We used sodium bisulfate (pH lower for swimming pools) and treated several days with buckets of the stuff. We finally gave it a muriatic acid treatment putting in around 10 gallons of the stuff. That kept the pH down around 5.0 that was on the acid side which is just as bad as a high pH. We waited a week and then tested, it had risen to between 7.5 and 8.5. The client wanted the water lilies asap not really understanding the problems with new concrete ponds. We then waited for another two weeks, testing the pH on a weekly basis. The pH level had stabilised between 8 and 8.5 so it was time to install the lilies. So at the end of January this year we installed 30 water lilies. Yesterday Tuesday, after six weeks in the pond, I went to fertilize them and to remove all the dead leaves and flowers. There was one that I needed to replaced, but that was not too bad given the water conditions. It resulted in 4 medium garbage bags of debris. I spent 3 hours in the water doing this. Each plant took 8 fertilizer tablets, it was back breaking work but I thoroughly enjoyed it. I enjoyed their intoxicating perfume and the Kaleidoscopic arrangement that surrounded me. The pH is monitored on a weekly basis and we will continue to treat it if it gets out of hand. The fish are in the pond now so we have to be very careful not to lower the pH too rapidly since any sudden changes will kill the fish. I mentioned to the landscaper that the pond could take another 10 more water lilies but he says he will wait and see how they grow. I will check the lilies in the pond in another 2-3 weeks to see how the fertilizer kicks in. Water lilies are heavy feeders and must be fertilized regularly every 4-6 weeks.