Causes of Ph drop??

[ScottoMacD]

Yesterday I noticed on of my fish in one of my tanks (33 gallon) acting a little odd.

The rest of the fish in that tank were fine and my other tanks all seemed normal. (Later proven by a water test) all other specs in all the tanks were within normal range, and almost all the same for all the tanks.

Nothing has changed recently in the tank. Water maintenance was on regualr schedule. ( that is what I was doing when I noticed) That is done the same time as the other tanks in the house. Once a week 33 to 50 % water change.

The food was the same, as always, nothing was added or removed from the tank.

Anyway when I tested the Ph on the 33 it had dropped to 5.
I tested all the other tanks right away and they all were at the normal 7. So it was just this one tank that dropped.

I did a 50% water change and tested it again and it was back up to a normal 7. I tested it a few hours later and still normal. Then once again this morning it was tested and it was normal.

I'm wondering what the opinions/thoughts are why this tank alone dropped off? After being regular for all these years? Why only this tank and not the other six?

The tank uses an AC300 and a powerhead 402 with a filter basket.
All the ornaments (driftwood etc) have been there for years. The plants are silk. The bioload is a bit heavy, but nothing has changed in the tank for the last 6 months. This tank is my transition tank, so some of the inhabitants are permenant and some are only temps. With the last temp being put in there 6 months back, and to be removed in a couple of more months.

I don't really think that this a problem. I just found it odd that only one tank of many had this happen, when all the tanks share the same maintenance schedule, water supply, types of filtration, species of fish, and food.

Thoughts?

[Cloud-9]

That is strange. Unless your water is very, very soft, it would take a lot to drop the ph down to 5. I believe each unit drop is a very big change. A ph of 6 is ten times more "acidic" than a ph of 7. I would think that your fish would have died from such a drastic shift. Is it possible that the ph shifted downwards, but perhaps not that much? Perhaps your test kit may have gone astray?

[Mr.Jingles]

I think that you could have misread the tests results, or the results could have been wrong. maybe the tube had some chemicals in it before you tested or something.

if nothing was wrong with the test, I imagine, if Im not wrong, that it could have been due to your large bioload. Im not sure, so someone correct me, but I think that if ammonia builds up for too long, it craps with the water and the pH can drop. not sure if Im right...

anyways, dont worry about it if your pH is normal.

[ScottoMacD]

Nope.

I figured that it was very drastic also. I have 2 different tests that I used. One is a very accurate test the other is a little more vague/general.

The both gave me the same reading within one or 2 points.

Edit: One more thing. If it was the test that crapped out. Then the other tanks would have been all over the map as well. They were all fine.

Like I said. I just thought it was weird. But not really a concern. I just was asking for some collective opinions. They are apperciated.

[dave76]

any ammonia readings?

[RTR]

Monitor your KH for a time. If heavily stocked, normal nitrification can burn out the alkalinity in the tank.

Monitoring for ammonia and nitrites would also be wise in case lasting damage was done to the bacterial colonies during the pH crash.

[jimbo]

Perhaps this article could help you finding the cause.

http://www.cichlid-forum.com/articles/gh_kh_ph.php

Jimmy

[ScottoMacD]

Originally posted by jimbo
Perhaps this article could help you finding the cause.

http://www.cichlid-forum.com/articles/gh_kh_ph.php

Jimmy

Thanks I just printed it out and will read it tonight when I get home.

RTR: Thanks I will keep an eye on it.

Everyone else you answers were much apperciated.

Thanks.

[scott]

I didn't read the link yet so I don't know what its about but my guess would be that your tank experienced bioacidification. I learned about this one the hard way as well.