I wouldn't add it if it's for pools, I think you'd be better off trying to equalize with water changes for the time being, if you can't get the stuff for ponds. I know you're pretty well educated about ponding (I read your other post), so I'll spare you the readout on chemical vs. natural pond maintenance. Just too bad you'll be fighting with this for the long haul.
Honestly, my best suggestion would be to use a natural substance in your filter that can raise the PH. Peat moss (lots) is a good method.
Peat moss or other naturally acidic additives will (in my opinion) provide you with a more stable solution. It is my opinion, that relying on PH up and PH down or other chemicals can provide you with a temporary balance, but you already know you're fighting a battle and the more stable you can make it, the easier time you'll have.
Do you know how long to expect the lime to leech out for? Is there no way to drain the pond and treat the concrete? If you could do that and not have the lime leeching out, it would be best (I know you know this already, just talking out loud).
In short, I'd be very hesitant to use a PH down for pools. Humans and fish have very different tolerancies, and we're also talking about invertebrates, amphibians and plants that could be harmed if there is an additive present in pool chemicals that you would not find in pond ones. I suppose my bias against chemical alterations (because they're temporary and could cause a sudden fatal crash to an already unbalanced system) makes me say this.

I still suggest multiple partial water changes to help lower PH in the first place, and then peatmoss in your filter or other acid leeching substance to counter the limes effect. If you're able to drain the pond and treat the concrete, I still reccommend the peat moss to counteract your Arizona hardwater in the first place. :)

Good luck!

What is high PH? I do not worry about my PH. It runs around 8.0-8.2 Some of my fish are sixteen years old so I don't think they mind it to much. I have feeder gold fish so Koi may be another story

Azponder, How high do your strips test? I assume that this isn't the first time that you tested your pond. What was your other readings?
Mike

Destany: I know about building ponds, only because I researched them to death before hiring my contractor. Day to day upkeep I only know from my little 300 gallon preform I had prior to my new one. Maybe I made myself sound like I know more than I did in my previous posts :)

Mike: The pond has been running for about 2 months now. My plants aren't mature yet, but I have a bio filter and a nice bead filter that are specced for double the volume I have. The only culprit I can think of, is the concrete leeching or my plant food tabs are dissolving to fast (they seem to crumble the moment they hit wet soil even before I can push em in).

From day one my hardness was 200 but the PH kept creeping up and then spiked (though it was 2 weeks since I had tested). Alkalinity on my strips is hovering between safe and high.

Here are my readings.

Nitrates 10-20

Nitrites 0

Total Hardness 250-300 (comes out of the tap around 200 :(

Total Alkalinity 200-300

PH level around 8.4

The PH on my strips says I am in the Danger zone.

I am at a loss as to how to fix the hardness as water changes only raise the hardness according to a local dealer. Since our water is so hard here, the minerals just build up through evaporation. I have a water softener on my inside water, but was told that water is bad for plants.

Azponder I don't consider those reading that high. My Hardness and alkalinity runs 400 to 450 and the ph is 8.3. I would not be too concerned about your readings. Do water changes and see if the ph and alkalinity readings come down.
Mike

I wouldn't put it past the company that makes the strips to label things "Danger" a little too quickly, considering it says right in the instructions a product they sell to adjust each of the readings.

My thinking about water changes though is that I will keep making the water harder though won't I? Since the water going in is so hard? Trying to fight PH, won't I be making another problem?

Water changes will not make the water harder since the water going in isn't any harder than what is there already. If it is a little lower like you said it will lower it just a little.
Mike

If you pH is stable, I would leave it alone. The pH is a little high....but certainly NOT dangerous!! It is far more dangerous to start shifting it around with chemicals. Companies that sell chemicals love to make you think your pH needs to be fixed to they can sell stuff.

If you pH is stable, I would leave it alone. The pH is a little high....but certainly NOT dangerous!! It is far more dangerous to start shifting it around with chemicals. Companies that sell chemicals love to make you think your pH needs to be fixed to they can sell stuff.

Ditto!