High Ph

The Ph is currently reading 8.0+ in my tank that is still cycling and has no current inhabitants. I decided to test the water in my beta's tank, who I have had since December, and the Ph in that tank is also reading that high. The water in both tanks reads clear of ammonia. Is this alright or is there a way to lower it without chemicals?

It is hard to know without a bit more information about your tank. Is there only water in it currently or do you have a sand/gravel/rock substrate? Have you tested the water you used to fill the tanks? Perhaps it was high to begin with. The other possibility is substrate. I had a problem with high pH in my tanks and it turned out my substrate had carbonate in it, buffering my pH so that it was around 8. We found this out by checking the source water (pH of 7.6) and realized it must be something in the tank causing the high pH. I checked the ammonia levels and they were nil, so I knew it couldn't be the water. It had to be the substrate I was using. Sure enough, when I tested the substrate with muriatic acid, it fizzed. I had to tear down my whole setup and replace the substrate with 99% silica sand (it's inert and won't mess with the water quality) I had to clean out the filter as well because some of the sand had gotten in and was still wreaking havoc! It fixed my water quality issue right away.

That being said, if it's your source water, and you don't want to use pH down, you might need to switch to bottled water (don't use distilled. It is harmful because of the lack of dissolved minerals in it). Bottled water tends to have a relatively neutral pH. I'm still pretty new to all this, so if I am wrong, please correct me!

The tank has a sand substrate, plastic plants, and a couple plastic hides. The filter has an activated carbon pouch, though I'm not sure that's affecting anything. I think it may actually be my water. My house isn't on city water, it's actually brought up by a well, but it's very clean and completely drinkable. It's quality is outstanding. That being said, I think it just has a high Ph. I tested the water in my smaller 5 gallon aquarium that has completely different substrate (gravel) and the Ph was slightly lower, but I think that might just be due to the fact that my 20 gallon has only been cycling for a couple of days.

Besides bottled water, would reverse osmosis water be a good path to go down, or is a Ph above 8 even worth messing with? Thanks again for the help.

& by reverse osmosis, I mean the jugs they sell at the pet store in the aquarium section.

Do you know if your area has a lot of limestone in it? Limestone will raise the pH of water and then buffer it due to a high alkalinity (it will resist changing the pH, even using a pH down chemical so you would likely be unable to adjust the pH down) I'm on well-water myself, but fortunately we don't have a lot of limestone here and the water comes out of the tap relatively close to neutral. I had to check it right from the well to be sure!

I think RO water has the same issue that distilled would have as typically the reverse osmosis process removes a lot of ions/minerals from the water. If they are selling it at the pet store, though, they might have re-added the minerals after the RO process, making it a suitable choice for an aquarium. I think you would just have to check the mineral content (which should be on the label) to make sure you have the ions your critters need for survival.

I'm not sure how to check the limestone content of my well water but it does have very high alkalinity. I'm going to take a couple water samples to the pet store later today to be tested, but I doubt my Ph is very alterable. I could put a few minnows in the tank and observe how they do?

I'm not sure how to check the limestone content either. I think if you have a lot of limestone in the area (a pale coloured rock), it would be safe to assume that you have some in and around your well or at least that it would be affecting the water in the well. It's not harmful, it just buffers the pH high. If the alkalinity is high, you can still overcome the high pH, it just takes more chemicals (an acid - you can buy pH down but you'll have to add a bunch of drops). Basically, there are carbonate ions in the water causing the pH to be higher. To reduce the pH, you have to 'use up' the carbonate ions by adding in an acidic substance. The hydrogen ions (H+) from the acid will give you a lower pH as you use up the carbonate. The trick here is that the pH will remain relatively constant until you overcome all the carbonate ions, then it will plummet sharply. You will probably have to add a fair amount of pH down. As a result, if you are going to try to reduce the pH in your water, you will have to monitor very closely as you add in pH down. It's still do-able, but you might want to get your pH stable before adding in your critters.