ph

Question
I just set up a new 10 gallon aquarium.  The pH is very high(8.6).  How does this affect the fish (I have none, yet)and how do I get the level to 7.0?  The store suggested replacing part of the water but did not suggest an additive.

Answer
Hi Sam;

I don't usually recommend messing with the pH at all but 8.6 is a little on the high side. It is best not to use an additive to alter it though. Chemical alteration of the pH can cause fluctuations that are more harmful to your fish than leaving the pH where it is and letting the fish get used to it. What we are looking for is a stable pH, not a certain reading. Don't just try to shoot for getting it right on 7.0. That's a very tall order considering where it is now. Just getting it down more reasonable, even 7.8 or 7.4 for now and keeping it at that one spot should be your goal. Depending on the pH at the fish store where you buy fish, it's fine. In such a small tank the Ph could be especially tricky to control too so the least intervention is best. Here are some other suggestions;

If you have any shells, coral, limestone or marble in there as decorations take them out and change the water. Those rocks are alkaline in nature so they will dissolve and always cause the pH to rise. There is nothing you can do to them, short of coating with a thick layer of epoxy, to make them stop doing that. Also look at your gravel. Crack one of the gravel pieces in half and see if the inside is white. If so, you were sold epoxy coated "dolomite" and unfortunately very common. It can cause the pH to rise in spite of it's epoxy coating because the coating is far too thin. Get a gravel called "Pebble Rock". It is not going to alter the pH significantly because it is tiny crushed hard rocks, not crushed  alkaline rocks.

You can also replace part of your tank water with bottled "distilled" or "Reverse Osmosis" (also called RO water) water every time you make your weekly 25% water change. Distilling and RO processes remove all the minerals from the water. You don't ever want to use straight distilled or RO though, just partly. Your fish do need some minerals and they would get weak and die over time without it. Let the water circulate for a few hours and test it again.

Another option is to keep a piece of driftwood or bogwood in there. It releases tannins into the water so that the water is softened and naturally becomes lower in pH. The water may be colored a bit brownish but just change the carbon in your filter more often (weekly or more often) and it will usually keep it under control but still allow the softening effect.

Using "peat" in the filter is a possible option too. Or, make a solution in a separate storage tank for your "peat water" and add it for part of your water change. It can be complicated but the idea is to make a "tea" from peat and use some of it in the tank water to soften it. Boil the peat in some water and them pour the whole sloppy mess into a big plastic storage container, such as a 30 gallon new garbage bin. Use some for replacing part of your water every week. It's nice and acidy after a while and will lower your pH.

Whatever method you use, monitor the pH and measure General Hardness and Carbonate Hardness very closely to see where it's going.

Here are some web pages to help you more;

http://www.firsttankguide.net/ph.php

http://www.thetropicaltank.co.uk/ph.htm

http://www.drhelm.com/aquarium/chemistry.html

Here also is a link to my own page about new tanks to help you through the first few weeks;

http://www.xanga.com/Expert_Fish_Help

Good luck with that pH...

At Your Service;
Chris Robbins