CichlidFish.com - Fish That Think.

would anyone like to comment on water chemistry for oscars? i have a 300 gal with sump (est. 8/04) with several oscars and a few community fish (i.e. silver dollars, tinfoil barbs, plecos) with three big pieces of treated driftwood. i make a weekly +-50% water change. my pH has slowly dropped from +8.0 to a current 6.8. What concerns me is my alkalinity has dropped from a high of 100 to about 0 (or just very low). Should i even care about this? Should I add a buffering agent? How about salt?? The fish are fine and seem to be thriving and happy. Is this a mess ready to unfold or is this a pointless concern? I have done an extensive search and have got several ideas from the saltwater and reef cichlid communities but i would like to hear from veteran keepers of oscars. Any input will be greatly appreciated : )

Should i even care about this?

nope,I wouldn't worry unless for some reason your PH follows and drops below 6.6


If you want to add something to buffer the water crushed coral is the safest and cheapest way to go. Just put some in a filter bag or a nylon and put it in your sump (out of sight).

thanks for your reply. As a matter of fact that night I wrote my first entry my pH was down to 6.2 I have three good sized pieces of drift wood that helped bring it down. In desperation I finally took the advice I found from one site that suggested adding sodium bicarbonate (to increase total aklinity but not necessarily to raise pH). I finally got the total akalinity up to 120 ppm but the pH went up to 7.8 almost as high as it was when I started the tank this past summer. I raised it slowly a little bit over two days. I have been concerned over this because my test kit states the total akalinity should not drop below 120 so as to get an accurate reading on pH. I really don't like to add anything to the water unless it's absolutely necessary (i.e. stress coat during water changes) but the pH and total akalinity are improved and the fish continue to be happy : ) thanks again!

Your honestly better off not using chemicals as levels can drop/rise suddenly and often do overnight if not done right. This where the real harm happens. The crushed coral would be your best bet in the long run.
I also would suggest only 40% max water change at one time or if you wanna do 50% then split it into two 25% weekly changes.