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fgump
07-20-2007, 12:48 AM
I went on vacation for a week. When I came back, my pH was 0.2 higher than normal. I'm not concerned about 0.2 increase, mainly wondering what would cause the pH to raise. And I will gradually lower it with my normal water changes - hopefully anyway, unless there's a bigger problem going on than I think.

My aquarium is only about 3 months old. And my aquarium water has always been 7.8, which is the pH of my tap water. The only things I add to the water are Prime and fish food.

And since I know it's going to be asked, my water params are:
Ammonia: 0
Nitrites: 0
Nitrates: ~10
pH: currently 8.0, but is normally 7.8

I have a 29 gallon bow front tank. Current inhabitants are 5 trili cories, 1 black molly, and 1 apple snail that's about 1/2 inches (maybe slightly larger). The tank has no live plants.

Aphotic Phoenix
07-20-2007, 12:53 AM
One likely possibility is calcium carbonate or other buffer minerals leeching from the substrate, rocks, or other decorations (sea shells or corals would be a prime example if you have any).

fgump
07-20-2007, 1:02 AM
Only thing in my tank is plastic. Only fake plants (for now), and no real rocks. Just plastic stuff I bought at PetsMart. And the substrate is the standard aquarium gravel you get at PetsMart also, no sea shells or coral in it. I do have a piece of driftwood soaking that will go in this weekend. But it's not in yet.

The charcoal in my filter has been in for about a month, but I doubt that could cause it.

ct-death
07-20-2007, 6:37 AM
TDS can slightly increase ones pH. Obviously not all dissolved solids will have a direct impact, but many do. Over time a tank's pH will rise slightly if not maintained.

I help out at a LFS and she has UGFs in all of her tanks. Every 3 weeks she tests for pH ONLY. Usually after 6 weeks her pH goes from 7.6 to 7.9 and she changes the water using this as a guide :shrug: Now that's only 0.3 change over 6 weeks.

Just throwing that out there ;)

jm1212
07-20-2007, 2:33 PM
what is the pH of the water straight from the tap?

what type of filtration is on the tank? filters that oxygenate the water like air-driven UGFs and HOB filters drive out CO2, which makes the pH of the water drop.

PiQ
07-21-2007, 4:27 AM
Not sure if this is helpful.

The straight forward answer is the fishes caused the pH to increase.

The fish excrete their nitrogen metabolic waste into their surrounding as ammonia. The ammonia is a base, or alkaline if you prefer. The pH of the tank will increase if you add base to it.

jpappy789
07-21-2007, 11:08 AM
^Not true. If the tank is cycled all ammonia should be converted...once all fish waste is change into nitrate (nitric acid) the pH should lower, not raise.

PiQ
07-21-2007, 12:15 PM
Oh, I never consider the conversion to nitrate. As you can see I'm new to this aquarium business.

This might be little bit off topic.

But if all the ammonia are converted to nitrate shouldn't the pH return to the original level, not lowering it?
Nitrate and nitric acid are two different species. There is no hydrogen on the nitrate molecules to deprotonated, therefore it shouldn't lower the pH when the bacteria convert the ammonia to nitrate.

Please let me know if I'm wrong in my reasoning. Thanks!

jpappy789
07-21-2007, 2:12 PM
I don't now...this is where i got my info...http://faq.thekrib.com/begin-chem.html

wikipedia also states that nitrate is a "salt of nitric acid"

http://en.wikipedia.org/wiki/Nitrate

silentskream
07-21-2007, 9:38 PM
uncycled ammonia will increase the PH, yes.. but according to the measurements indicated at the beginning of this thread, there is no ammonia. it has ALL been cycled.. soo it probably isn't the cause.

you aught to check the hardness of your water.. extremely soft water will sometimes change ph quickly.

how were the fish taken care of while you were away? did you have vacation feeders? automatic feeders? a friend come check on them? or did they just tough it out for the week?

johnlarson66
07-21-2007, 10:04 PM
I think when you put the drift wood in, you will notice that your pH will drop a little bit below your tap water.

CC917
08-27-2007, 1:47 AM
If you keep adding "tap water" for evaporated water, the Ph will keep increasing, as when water evaporates, only "water" is lost. Minerals stay in the tank. So, when you using tap water for top-off water, you are just adding more minerals to your tank.

I learned this after I found ph from my tank increased so much. I serached all the information I could find and realized how this happened. Therefore, for small amount of evaporated water, please use pure water instead. I personally use RO water. This will solve the problem.

nynikki
08-27-2007, 10:39 AM
While on vacation, did you have any casualties? Wouldn't a corpse increase the PH?

fgump
08-27-2007, 12:47 PM
Wow, this is over a month old. Hmm, to answer some of the questions asked.


what is the pH of the water straight from the tap?

what type of filtration is on the tank? filters that oxygenate the water like air-driven UGFs and HOB filters drive out CO2, which makes the pH of the water drop.

pH of the tap is 7.8, and the tank is normally 7.8. It's a HOB filter (penguin 150 to be exact) .


you aught to check the hardness of your water.. extremely soft water will sometimes change ph quickly.

how were the fish taken care of while you were away? did you have vacation feeders? automatic feeders? a friend come check on them? or did they just tough it out for the week?

The GH is around 12 ppm, with KH around 10-11 ppm. And I was using an automatic feeder. It is a cheap one, and only holds flakes. So my cories would have had to eat any left over flakes that made it to the bottom - they normally get shrimp pellets.


If you keep adding "tap water" for evaporated water, the Ph will keep increasing...

I might add about 1 quart at the most a week if the water gets to low before my weekly water change. But that's always taken care of within a couple of days with my weekly water change. So there's really no chance of build up. And this all happened within a week while I was on vacation.


While on vacation, did you have any casualties? Wouldn't a corpse increase the PH?

No casualties were involved.


And for an update. Once I did my water change, the pH went back to 7.8. And I haven't seen it change since.