I have hard alkaline tap water but I noticed an interesting thing when I used it to fill a half-barrel minipond on my deck. After I put in gravel and plants and a small fountain, then let the whole thing cycle, nature corrected everything that was wrong with the tap water. In fact I use it now as the source for water changes in my aquarium -- much better than trying to fix all the tap water problems with chemicals. Even when it's going through one of its "pea soup" phases I add a bit of its water to the aquarium. The lighting there isn't enough to let the algae take over, and the fish seem to love the infusion of micro-flora and -fauna. I've never had the transfusion cause any disease or parasite problems in the fish tank either but maybe I've just been lucky.

The PH is not as big a problem as the water hardness (KH). The KH sould read above 150 ppm at least. I have the same problem and add 1lb of baking soda per 1000 gallons to bring it up into that range. You should get a good test kit that reads out in numbers, not just colors.

For the temp I would recommend floating plants such as water hyacinth.

Matt

I have country well water. When I first filled my 1800 gal pond in April of 05 I was concerned about my 'ph' readings. I use the 'Pond Care Wide Range PH test kit', liquid drops in test tube, and the readings were always at the high end, 9, alkaline side of the test range. I thought the reason might be the stone used in the waterfall and the border stone, but the water itself tests high alkaline right out of the tap because of the mineral content.
My pond has consistently checked the same for 3 years now, 9, high end of the chart alkaline, and everything appears to be doing just fine__fish, frogs, plants. Well, at least I haven't heard anyone complain yet. LoL. The pond ph factor is something I never really fully understood and there are a lot of factors that come into play that can influence the ph. Maybe some of the specialist here will chime in.
I'm going to say that plants are a must for any water environment, unless it's a hottub. I'm no plant specialist but you'll need a variety of floaters for shade, which will keep your water temp a little cooler and submersibles as oxygenators. I think I remember reading somewhere about a '60% rule of thumb for surface coverage'. I'm sure others will ring in here as well.
"Sorry for all the questions". That's what the forum is for and the people here are glad to help. Fire away!

Witz

What exactly are the numbers for pH and kH? fish will adjust to high alkalinity and hardness. Stable is much more important than the actual numbers, and with alkalinity, your pH should be pretty stable. Do not try to bring the pH down with acid or peat or anything else. Trying to adjust pH causes it to be unstable.

As far as temps go, 90 is pretty warm. Do not feed the fish at these temps. Aeration is very important at high temps because warm water holds less oxygen than cooler water. Plants will not help, and can hurt because decaying plant material use up oxygen.

My pH is around 8.4, my alkalinity is between 180 and 300(closer to 300) and my hardiness is 300.
The temperature reached about 88 at the peak of the day. I do have two waterfalls that produce a good stream of bubbles, but i don't know if that's enough to support the pond in terms of aeration.

don't worry a bit about your pH or hardness. The fish can live with that perfectly well. The only thing you may see from time to time is little black spots appearing on some fish. They are called Shimis. They are just dark pigment spots that cause no harm at all. Hard water is the culprit. You may have trouble with some varieties like Asagis that prefer softer water, but otherwise expect no problems.

You can't have too much aeration. If your water is getting very warm and staying that way, pay close attention to how the fish act. Of you notice them hanging out under the waterfalls, they need additional aeration.

Your pH, alkalinity, and hardness are fine. See the link.

Here is a link that might be useful: is your pond running on empty

I added a few fish yesterday and overnight, they all died. So I'm really scared to add fish in.

Are you using chlorinated tap water? Did you use dechlorinator in the water? Chlorine will kill fish.

I did a water test and the chlorine, nitrate, and nitrite levels are perfect.

did you float the bags the fish were in to acclimate them to the temperature of your pond? If they came from cool water and got dumped into a hot pond, the temperature shock could have killed them. How fresh is your test kit? Is it a strip test or one with test-tubes and drop chemicals? Do you have city water and do you dechlorinate (regardless of what the test kit says)?

One trick I learned from more experienced ponders on this forum is that alkalinity can be reduced to better levels by putting a slug of Plaster of Paris in the water. As the alkalinity gets too high, the PP chemically reacts and lowers the level. If the level is not too high then there is no reaction. I keep a couple of molds handy to make decorative slugs and the water around the slugs seems always to be clearer and the fish congregate there. Sandy

You can do much more harm than good by messing with ph/hardness. Changes are worse than constant high ph. Plenty of ponders are successful with readings like that. I'm going to assume you are in Southern CA where those type readings and temperatures are to be expected.

If you are in Southern CA, there are a bunch of ponders in that area with loads of experience and extra plants and maybe extra fish that are members of the American Ponders forum.

Having fish die in a brand new pond is common. You should add plants and let your pond cycle before adding any more fish.

Its a good and economical to get your bio started in a new pond with inexpensive fish. Take the time to get your filter colony set up. Then bring out the goodies SLOWLY.

I should have mentioned, the PP slug is good because it is slo-o-ow. I put a slug in 2 months ago and it is still more than half the original size in 1000 gallons. I agree with the others that it is usually best to leave things alone but in cases where the PH is so high there are mineral deposits on everything or foam, something should be done. Sandy

What kind of plaster is it exactly? Where would I find it?
I went to the fish store to get some minnows and the lady there told me my ph was way to high and they would die. So she convinced me to buy some ph down. So I went home put in about half the amount and then I saw mosquito larvae. If mosquito larvae can grow, does that mean fish will make it? Or are mosquito larvae so hardy that they will survive anywhere.
At any rate now I need to get some fish in there fast because those larvae give me the chills.

I use DAP - can get it at any local hardware store.

You want to look for the brands that don't have special hardeners or something to make it set up faster. Those just keep it from working properly. DAP works fine.

Of Course the saleslady would tell you that, so she could make a sale. If you want the people on the forum to help, you need to listen to them. They have nothing to gain when they tell you what works for them and they offer suggestions. My ph runs a little high, but my fish do fine in it and one thing I have learned on the forum is don't mess with the ph. When I first added my fish, I didn't know what I was doing and I filled my pond and the next day, in went the fish. Guess I was just lucky, never lost a fish, until the Heron came. Glenda

Put in mosquito dunks to kill the larvae and stop messing with the ph.

Putting any fish in a brand new pond is likely to kill them regardless of the ph. Ponds should cycle and be planted first.

Please disreguard everything I have posted here. I totally remembered "facts" incorrectly. I know better and said it wrong. You won't hurt anything by adding the PP slug but it will not reduce alkalinity in the pond. I apologise. Sandy