High Alkaline

Question
Hi Chris,

We have a 20 gallon tank that has been set up for 5 weeks. 2 platys (1 died), 2 mollies (1 died). We have aquarium gravel and plastic plants.  Our water is high alkaline and usually runs 7.5 - 7.6.  It comes out of the tap off-the-chart blue.  It measured 7.4 today after using 2 T. vinegar yesterday (recommended by Earl May Garden Center).  We have tried using ph down and we have siphoned off some water and replaced it with bottled drinking water, (which tested acidic). It lowers it, but then it rises again.  Do we need a water softener?  Earl May Garden Center tested the water and everything else was normal. We would very much appreciate your advice.  Thanks, Diane

Answer
Hi Diane;

The good news is that you don't need a water softener and you don't need to mess with the pH anymore. It stresses the fish to keep trying to alter it because it causes fluctuations. Fluctuating pH is stressful, but a pH of 7.5 or even 8.2 isn't a problem for them at all. Let it stay where it tends to be. It will go down a bit over time as your tank ages anyway. If you had a few fish die it was from the break-in period (aka; "New Tank Syndrome"), not the pH level. When a new tank has it's first fish added, there should be only one inch of fish for every ten gallons. If your tank had 6 fish in it, the toxin levels simply rose too high for them to tolerate. (More fish equals more toxins.) A 20 gallon should have only two one-inch fish or four 1/2 inch fish or whatever combination it takes to equal 2 inches. This break-in period takes 6 to 8 weeks to complete and no other fish should be added until done. I will include a link to my article on it at the end of this letter.

The fish you have in your tank now never lived in the same conditions their wild ancestors lived. Fish you buy in the fish stores now have been bred in captivity for many generations. They are raised in concrete breeding ponds that tend to be a bit on the alkaline side at 7.4 or so. Compared to that, your tank is just fine. Fish breeders have raised many types of fish, even those that "prefer a lower pH" in these ponds with great success. As a matter of fact, platies and especially mollies can tolerate a pH even over 8.5. It doesn't mean they need it, it just means they can live in that range.

So, make it easier on yourself and your fish and just let it be at a stable pH, and not what fish profile charts tell you is "right" for the type of fish. Here are links about it;

http://www.thetropicaltank.co.uk/ph.htm
http://www.aquahobby.com/articles/e_adjusting_pH.php

Here is a link to my article on new tanks so you understand what has been happening in your tank;

http://www.xanga.com/expert_fish_help

At Your Service;
Chris Robbins