tap water >190 ppmCa, Mg,130ppm HCO3(straight from the tap), pH 7.6, KH 7-8, GH 9. The plants did not do well in this water. The fish are all soft water species: some apistogrammas, gouramis, tetras, rasboras, loaches, corydoras. 21/2 years ago I kept them basically in tap water. However, after I started to provide them with 2/3 deionized and 1/3 tap with the lower pH their colours became vibrant - in fact, the photographs in the books don't do them justice. The fish are spawning - (except the loaches). There are no shells or any sedimentary type rocks in the tank. The substrate is non-reactive to acid. My fish have NOT come down with anything like ick or any other disease. They are very healthy, and even my zebra danio test fish lived for 21/2 years. (damn it. Who wants the test fish to live on, and on, and on. They were BLIND already! They ended up in their own "senior citizens tank"). I have raised gouramis, and apistogrammas. The other fish spawn, but I do not have the facilities available to help them out. The sex ratios of the apistogramma were very close to 50/50 m/f. They grow well and quickly without the addition of baby brine or any other special food. They seem to find plenty of "bugs" around the plants and the substrate. The parent fish are alive and well, although by Apistogramma standards, they are geriatric - especially the female. The plants are a variety of stem plants and chain swords, some cryptos, vallisneria, water sprite etc. The reason I have attempted to alter the type of water I am putting in the tank is precisely to stop creating a "chemical soup". The pH of deionized water is ??? Once I have reconstituted it, the pH is 6.6 GH 3 KH 3 No lfs salesperson has ever tried to get me to buy anything. However, I think the Mardel Waters of the World, and the Tetra Black Water Extract are misleading products. This is why I am trying to simplify things. I know that the tap water was not the best environment for my fish. They did not spawn, and their colours were muted compared to how they look today. All I am trying to do is create an environment where the fish are comfortable, non-stressed and "happy"- if it is possible for a fish to be so. It just seems that somehow the pH is being influenced by something - probably the phosphate, which results in the pH bounce. Considering the KH is only 3 - this alone will not create the bounce. There has to be something else - and it's not the presence of limestone or any shells. Right now, after titrating non-phosphate buffered acid into the tank, the pH has stabilized at 6.6. The problem will again arise when I do another water change. I think that until there is sufficient phosphate in the water, it will bind up hydrogen ionsand help to drive up the pH. (That's just my theory, I'm not sure, that's why I posted the original letter.) Today I added some phosphate absorber to the filter system and hopefully I can eliminate the huge excess. Please bear in mind that the phosphate level was far in excess of any test reading. Through dilution of the test solution I was able to extrapolate that the level was above 40ppm. At this time it is under 10ppm. and falling. I think the water will be better for the fish if there isn't all that phosphate in it. I also think that once I get rid of the high phosphate level, there should not be a pH bounce. Again, I don't know this for a fact. I am trying to get some info from people on this list who may be able to help me out here. I just wanted to find out from anyone who would understand the situation whether the problem arises through changing buffering systems. Part of the buffering system is just sodium bicarbonate. I'm not sure about the buffered acid. I realize that there are a lot of people who would advocate using the water coming out of the tap. If that's fine for them, well and good. However, I do not intend to once again use water straight from the tap. When I was a kid I kept guppies and when I had mollies I added salt to the water. The tap was fine. I don't want to keep rift lake cichlids, although that seems to be the fish of choice for most people in this city. When I started with fish again, I wanted to put species together that would not kill each other or fight. I prefer to have a relaxing experience when I watch my fish. My only other option is to move to the west coast where the water is wonderful for keeping soft water fish. Unfortunately, if I do that, it'll have to wait until I'm 65 :) This letter is too long, but I hope I have answered all of your questions. Insomnia seems to be my friend today. ------------------------------------------------------------------------- This is the apistogramma mailing list, apisto@majordomo.pobox.com. For instructions on how to subscribe or unsubscribe or get help, email apisto-request@majordomo.pobox.com. Search http://altavista.digital.com for "Apistogramma Mailing List Archives"!