in my 5 and 10 gallon cycled tanks, the pH is steady at 7.0 which is how it comes out of the tap.. I use Prime and age it before adding it..

in my 2 1/2 gallon unfiltered tanks I put the water in at 7.0 and within a day or two the pH has dropped to 6.6-6.8.. anyone know why this would be?

because of concern for my betta boys and the dropping pH I have been replacing their water 8 cups per day to try and keep the pH at 7.0 and changing their water completely once a week..

they seem happy enough, and are eating well, but I sure would like to know why the pH drops for them and not for the cycled tanks..

thanks very much in advance for any help

because your 5 and ten gallon tanks have more water, there is a larger buffer zone for the ph to remain stable. the nitrification process releases a lot of acids in the water, wich is causing your ph to become slightly acidic. the best way to combat falling ph levels in any aquarium is either stepping up water changes (like you have done) and/or raising the kh to a more optimum level. you can raise the kh of water by adding crushed oyster shells to the filter. but the water changes are a better option in a smaller environment.

incidentely, do you know the kh levels of your tapwater? if its lower than 100, youll easily run into this problem.

did that help?

My tanks are the opposite! My 55 gallon has a Ph that would drop from 8.2 to 6.8 in a week!!!! (I use crushed coral now, so no more of that crap).
Then the 2 gallon betta tank would hold a constant Ph.
Probably due to the 55 having poopy goldies in it, right?

toothless, yes you were a big help! Now I know that water changes are indeed a good option! the 2 1/2 gallon tanks don't have a filter because I read here that you can't cycle a 2 1/2 gallon tank? so its been partial and then complete changes once a week. I sure am thankful for pH test kits! thank you for helping me

im not sure about that info on not being able to cycle a small tank like yours. ive got a 1.5 thats got a very stable cycle. even with 50-75% water changes once a week (usually only 30-50%). and to top it off, its a mere undergravel filter set-up! if you want to get a very cheap and easy to maintian filter for a 2.5 gallon tank (for one or two bettas, separated, that is) look at these, they are powered by aerators and would keep your tank cycled all the time(once they were sufficiently colonized but, you can add them to a healthy tank for a week to do that.

http://www.bigalsonline.com/catalog/catego...id1=2885;pcid2=

or you could get an undergravel filter for your size container. again, theyre very cheap and run on air-pumps.

either way, it really is best to keep them in a filtered environment. unless your testing every single day and doing water changes to make sure theres no ammonia. witch, within 48 hours or so (in a 2.5), there would certainly be ammonia.

yes, religiously doing water changes/ gravel vacs is the best way to safeguard almost any fish from poor water conditions.

erika,

yep, goldie poop. thats why filters of well stocked tanks get such a build-up of filter goop. i think that goop is the bio-bugs (or maybe the remains of deceased bio-bugs. the live ones might build or attach to the remains of dead ones, much like coral. but, im still researching that)

paul

i forgot to ask, how often and how much water did you change?


you might want to try this little experiment:

take a jug of water from the tap, test the ph and then let it sit for a full 24 hours. test again. let it sit for 24 more hours, test again. see any drops in ph? if so, its because youve probably got cO2 in the tap water. its normal. it acts as a ph buffer for the water until it comes out of the tap and the cO2 dissapates. then the ph drops somewhat. if that is the case, youll have to age your water for a couple of days before using it. but, that doesnt explain the rock-steady ph in your big tank/s.

do they have some sort of substrate/ornament that might contain calcium?

do you add any supplements or buffers of any sort to them?

im somewhat perplexed all of a sudden, now i gotta do some brainstorming........

most likely, im right about the poop or detritus being the culprit though. anything acidic in nature will cause a drop in ph.

paul

I'd put a handful of crushed coral down as the substrate in the tank to help buffer a bit, or use baking soda.

You can indeed cycle a 2.5g tank, get a sponge filter and it's easy. My betta tank has been cycled for months. I change 50-60% of the water once a week.

Water of pH 7.0 and normal levels of co2 (with no phosphate buffers) has a KH of 1-1.5ppm, which is not enough to keep it stable. You want at least a KH of 2 for a tank that small, preferably 3-4. Mine stays stable with a KH of 2-2.5 and my normal weekly water changes.

Paul--


Was your last post to me, or to sixlittlefish?

sorry to be late getting back... just in case your last post was for me but I think it was for errrika

in 2 1/2 (closer to 2) gallons, I change 2 quarts every day and 100% every five days or so.. when I take the water from the tap it is 7.0 after letting it sit for a couple of days it is still 7.0

in the 5 and 10 I only have gravel and Aqua Clear mini filter.. 5 gallon has a crystal wine glass for a hidey hole, 10 gallon has two fairly large piecea petrified wood and some picture jasper as well as both have silk and plastic plants.

2 1/2 have silk plants, glass hidey holes and only the tiniest bit of gravel under the glass.. also a few pieces of glass beads.

I think I'm going to have to invest in a little pump and those sponge filters..

I do test pH every day and ammonia often too.. with the daily changes and weekly 100% changes ammonia does not show up.

sorry for the confusion. my last post was for slf. sounds like youve got the ph probs under control though.

something interesting!!

for the past few days, my betta Zacchaeus had developed a spot that looked like fungus on his dorsal fin.. anyway I isolated him and put some aquarium salt in the water.. I know that some people disagree with the use of salt, but 3 days the spot has disappeared, and even more interesting, the pH has remained stable at 7.0, same as it came out of the tap! I tested today and there only the very slightest amount of ammonia, not even .1 so I am supposing that salt can act as a stabilizer for the pH? because if so, I am going to add it to my other bettas in the 2 1/2 gallon containers to see if it will stabilize them too..

i wouldnt say that salt is a ph buffer. the reason why your ph stayed stable in the isolation container is probably because its a fresh clean slate. his regular container probably has a bit of fish poo and whatnots in the gravel (im assuming you have gravel). plus hwever few, there are bio-bugs in his tank if you dont completely scrub and clean everything in it. as i said before, the nitrification process is a known cause of ph drops.

did that make sense? ph is a very confusing subject and im not claiming to be an expert. just letting you know what my understanding is.

hope it helps

Normal salt does NOT buffer the water. The chemistry behind it is a bit complicated but I could explain it if you really wanted to know. The explanations toothless offered are probably correct.