Keeping the pH level down (7.0)

Merry Michael

This certain tank..(20 long),is about 6 weeks old,and still cycling. I've put some dither fish into it and they were doing great,corys and a couple platys(one even had babies!). For some reason,about every 5-7 days,this tanks pH level goes BLOOEY!! and exceeds 7.6! I then add pH down,wait a bit,take another reading,and wa-la! normal (7.0) pH. Which then lasts for @ 7 days...then boom,back up again.
What the heck am I doing wrong...or the tank? This tank has been nothing but trouble since I started it! My other tanks are well and healthy. Same water,conditioner,food...and fish!
Does anyone have an answer?...or solution??

MoneyMitch

sounds like your water soucre has little buffering capacity, just for kicks test your gh and kh and lets hear the results. i would take out any inert objects in the tank and be carefull how much you flux your ph with the buffers such as ph up,down etc. i think dolimite helps with buffering cap or maybe premix some w/c water with vinegar and test before you add. others will chime soon though

Merry Michael

thanx Mitch...just for "fun",I took a reading right from the tap...guess what,it read 7.0! So,I took a reading from all my other tanks,7.0! (and by the way,all the nitrites and ammonia readings are at 0). So,there IS something in that tank that's raising the pH. I'd take everything out,but what about the platy babies? they seem to be doing just fine..and I don't have another tank to put them in.But then again,perhaps I should sacrifice them to find out what's really going on with that tank? I'm going to take another reading now...I hate waking-up in the morning to dead fish!

Merry Michael

there just took another reading...I added a pH Down about 1 1/2 hours ago,and it still reads 7.6! This just creeps me out...everything else is spot-on except the pH. I think tomorrow Mitch,I'll go to my LPS and get some dolomite and really turn this into a science experiment...poor fish

iamntbatman

Dolomite (the mineral, not the guy from the movie) will increase your buffering capacity but it will also likely raise your pH, which is the opposite of what you're trying to do.

I would stop adding the pH Down. That stuff is basically acid in a bottle which does lower your pH but also destroys your buffering capacity, allowing your pH to rise again quite quickly if you've got some something in the tank that's raising the pH. (Come to think of it, that's probably an added benefit of the product in the eyes of the manufacturer, as it means you'll have to keep buying more of the stuff).

What sort of decor do you have in the tank? I'm suspecting that something in there is causing your pH to go up. Possibly some sort of rocks or seashells or something along those lines?

Merry Michael

Hi iamntbatman! Well,in the plant department,I'm lazy! So,I've got plastic plants and some of those "silk" things. I also have a plastic (?) type of "fake-O" tree limb. The substrate is natural type rock bought at the LFS. and..that's it! no sea-shells,nothing that the other tanks don't have! That's the puzzle!
Yeah! Let's nix the dolomite! Thanx!

iamntbatman

I'd test your substrate, then. Some say to use vinegar to see if it bubbles but vinegar is a pretty weak acid. Instead, grab the Nitrate Test Solution #1 bottle from your liquid test kit (you do have one of these, right?) and drip some on some of your substrate (outside of the tank, of course). You should see some fizzing if the gravel contains compounds that will raise the pH of your tank.

Is this substrate unique to this tank, or do you have it in several of your tanks?

Merry Michael

OK,just tried that (with the liquid test,bottle #1)...and,no fizzing of any kind! and yes to your question about it being in only this tank. *sigh*
The thing that gets me,those baby platy fish are actually thriving in this tank! The things that make a person go "Hmmm"!

iamntbatman

What species of cories do you have? Platies actually do pretty well in harder, more alkaline water so it's no surprise that they're thriving. The cories, on the other hand, might be suffering if that pH is seriously out of whack. Finding out the species of catfish you have as well as the exact pH of your water might mean the difference between struggling to fix the problem and just leaving it where it is.

Merry Michael

The corys...yeah,they prefer more acid water. They are Threestripe Corys,which I've got in my other tanks and are perfectly happy. But,you are right,I think I'll go to bed and see where this tank is at in the am.!
Gee thanx a bunch!! I'll check the tank tomorrow and perhaps do a w/c again. Never can do enough of those!
Thanx!