ph level drops every 2-3 hours

Question
QUESTION: I have a 10 gallon tank, set it up about a month ago since then a few fish died I have 2 fish left, I do water changes 20% every three hours because my ph drops below 6.0, I have mollies who like a higher ph. My question is what could cause the ph to keep dropping so quickly?

ANSWER: Hi Donna
Have a few questions....

Are you adding anything, any chemical ph products?

What's in the tank decoration wise-any driftwood or peat moss?

What's your tap water ph reading?  Also, take a glass of water, test the ph.  Let it sit out for about 12 hours and retest it.  Is it changing after sitting out?  This will let me know if it's your tap water or if it's something in the tank.

Are you running an undergravel filter by chance?

And, what's the ammonia, nitrite, and nitrate readings?

How low is the ph dropping?

Christy


---------- FOLLOW-UP ----------

QUESTION: I have added a little ph up but it didn't work so I didn't try it again, no decorations only plastic items, ph starts at 7.8 and the I can check it an hour later it drops down to 6.8 th another hour 6.0. no undergravel filter. amonia is 0 nitrite is o and nitrate is 0. below 6.0

ANSWER: Wow...that's not good.  Those latest readings, did you let some tap water sit out in a glass?  Or are those readings directly from your tank?

Are you on well water or city water?



---------- FOLLOW-UP ----------

QUESTION: I am city water and the pH directly from my tap is 7.8, and it has an ammonia of 5.0. I let the water sit out over night or longer but not in glass in  gallon plastic water jugs, could this make a difference? Now , one thing did happen in the past week the pH leveled out for 2 days to 7.4, but when I checked the ammonia and the nitrites they went up, the ammonia to 5.0 and the nitrites to I think it was 5.O. also, so i put ml of ammo block from API, and now I an having other same problem with my PH. Also my water is slightly cloudy now, not bad just a little.

Answer
Hi Donna
I'm not sure if I'm understanding you correctly...if you're tap water is showing ammonia-out of the tap, and it's city water, you need to be calling the water dept. first thing in the a.m.  I'm not an expert in that department, but I know that water companies are restricted on what is and isn't allowed in the water, and what levels are acceptable.  I can't say for sure, but I would imagine that level of ammonia in the water is not good.

Now, if that level is in the tank, that's a different story.  Your tank is new, only about a month old.  You were doing very frequent water changes originally because of the ph adjusting so rapidly.  That was most likely removing the ammonia, thus not allowing the tank to go through the cycle process, here's a link that explains that:

http://freshaquarium.about.com/od/startupcycle/Step_5_The_Cycle.htm

Which would explain why now, your ammonia is showing up(again, this is assuming that's where it originated, not from the tap water faucet).  That's also why the water is cloudy most likely, if it's a white/greyish color, it's a bacterial bloom-the beneficial bacteria starting to colonize.  Again, read that link I just posted, that will explain it further.

Now for the ph....that's still a puzzle.  How deep is the gravel bed?  And, before you started doing the 3 hour water changes, how often did you do water changes?  And how many/what kinds of fish did you have originally?  One thing that can lower ph, if there's lots of uneaten food or waste in the bottom/gravel, that can bring it down.  I dont' know if would necessarily do it that quickly, I'm going to have to do some more checking on that.  Another thing, do you have a test kit to test water hardness?  GH and KH will also affect the ph....now we're getting technical, and out of my realm :)  I'm going post another link that explains that as well, much better then I can....

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

Are you by chance using reverse osmosis water or have a system set up in your house that you use?

Christy