problems with ph

[bongobrian]

I can't figure out any possible explanation for what is happening with my ph. I've never had a problem keeping the ph up, it's always been between 8.4 and 8.6 without adding any buffers or anything. Just recently I lost one of my fish.. and I think it's due to the drop in ph. When I tested the ph while the fish was having probs.. it tested at 8.0 with the lights on. Naturally I added ph buffer to bring it back up. After the fish died and a few days later, the ph is back down to 8.0. The weird thing is.. my alk has been quite high at about 4.0 meq/l and I havn't been adding anything that would bring the alk up that high. I'm just trying to figure out why the ph keeps dropping and why the alk would be so high. I always thought the alk level is the tanks ability to "buffer" the tank and hold the ph at a stable level. I know the acid in the tank mostly comes from the hydrogen ion which in turn comes from the respiration of animals (CO2) in the tank. The bicarbonate ion also comes from CO2 and the level of bicarbonate is essentially what alkalinity is. So the only thing I can think of is that by adding more CO2 to the system, it would produce more hydrogen ion resulting in a lower ph, and also more bicarbonate ion resulting in a higher alkalinity. That's really my only explanation on what could be causing this. I just can't figure out where all this extra CO2 would come from. I've only added one small fish and a cleaner shrimp recently. Do you guys have any thoughts on this? Do you think the opposite could be happening where somehow there is an abundance of hydrogen being added to the system from some source? causing a drop in ph? but then that doesn't explain the high alkalinity. Thx guys! sorry for the mini novel ;)~

[Poseidon]

Wow...

Brian it sounds like you've really put alot of research into the problem...the only thing I can think to do is a large water change and hopefully that will "dilute" whatever is lowering your pH...

I know that sounds obvious but its all I can think of...

Mike

[bongobrian]

Thanks for the reply poseidon... yeah a water change would probably help but I'm really trying to get to the bottom of this and find a long term fix. It was my favorite fish that died, so I really want to prevent this from happening again. I've really been slacking off on doing regular water changes... but it's because I havn't had any problems at all up until now. In fact, things have looked better than ever. I guess that probably could have contributed to the problem and it's something I never thought of. Thanks.

[Poseidon]

no problem Brian

I would be the same way I would want to find the cause rather then treating the symptom, but this is at least a start...

Mike

[CoralHead]

I know this problem was a while ago! BUT...did you ever figure out the problem? I just read the thread and realized that the majic word 'magnesium' was never mentioned. That's important. Let me know if you have any questions. Sorry I wasn't able to give that info to you 2 years ago! Anyways, have a great night!