pH drop?

[bluerose]

Last time I tested my pH (admittedly a few weeks ago) it was a nice 7.2...

Now I'm guesstimating it to be at 6.2. Definitely in the low-mid 6 range.

I'm having some troubles with plant die-off on one side of the tank... but the ammonia level doesn't seem to be affected...

any ideas? I did add a piece of driftwood but it was soaked well beforehand and it's been in there for a couple of weeks (added it a couple of days after I last tested pH probably)...

The fish seem happy enough but I'm just curious in case it's something I'm doing.

 

[Purrbox]

Driftwood is known for lowering pH. The degree that it lowers the pH depends on the type of wood and the size relative to the size of the aquarium.

Decaying plant matter can also lower pH. You should remove dead leaves, etc rather then letting them rot in the aquairum.

 

[bluerose]

I've been doing what I can with the leaves... except that if I turn the filter off to get at them they get un-stuck from the filter basket and float everywhere so it's a little hard to nab them. I'll work on it again.

Didn't know decaying plants could lower pH- makes sense though because some of my anacharis are not so happy...

 

[bluerose]

OK. Got rid of a lot of plant matter (went through all of the not-emerald-green plants and snapped off what easily came off/looked poorly) and did a bit of rescaping, the fish seem happier with the new arrangement (one of the cories was swimming loops through the arch in the driftwood last night and the tetras are hanging out in the front instead of in the back by the filter intake).

I'm guessing I should let the pH right itself slowly with standard 25% PWCs instead of doing a big change all at once? Everybody's happy and healthy and active.

 

[bluerose]

Did my weekly 25% PWC yesterday. Vacuumed half the gravel I can (live plants and whatnot), got some dead leaves out of it. I used half spring water (pH 7 I assume) and half warm tap to get the water temp closer to the tank's.

pH is now 6 and I would guess maybe even 5.8...

On a hunch I tested my tap water and it is 7.6 if not 7.8 (card goes from 6-7.6).

I pulled out all dead leaves and weak looking/dying plants, I rinsed the filter and filter pad free of all gook (including bits of dead leaves- and I used tank water, no worries), I treated the water with dechlor and swished it around well- the only thing left seems like the driftwood but it's been in there for long enough that it shouldn't be still releasing tannins, right??

The water is crystal clear, ammonia 0, nitrites 0, didn't test nitrates today but last week they were 5.

ACK!

I want to get some more fish now that I know my biofilter is well established...

I'll try to find some time to do a more thorough gravel vac this week (will have to pull the fish out, they have a habit of getting way too close to the gravel vac for my liking) to get it really clean- do another PWC- see if I can work that pH back up towards normal.

Any other suggestions? Obvious things I'm missing?

 

[diogenes]

could be phosphates. Negatively charged ions can bring you ph down. Right now my tank is cycling and I have so many nitrites that my ph is down more than a point.

 

[bluerose]

Except my tank has been cycled for several weeks and the nitrite count is 0... could this still be a factor?

 

[Purrbox]

Have you tested your KH? I suspect that it's probably very low to non existant, which means you'd have very little to stabilize your pH and it could change easily.

 

[bluerose]

I have not tested the KH (doesn't come with the API kit).

If my KH is low, what would the fix be for that? From the reading I am doing it seems that the fish breeds I have do OK in low pH water but the female betta I am considering would not.

 

[Purrbox]

Unless you're trying to breed your female betta should be fine.

 

[jsoong]

If your tap is 7.6 - there should be enough KH in there .... unless you have dissolved CO2 or some other problems.

1st thing I would do is take a sample of tap water, test the pH immediately & after sitting out a day or more in a container. If the pH drops in the sample, it is something in your water (likely CO2) that is causing the drop rather than something in your tank.

 

[bluerose]

joosong- thanks!!

will do immediately.

again though, just for curiosity's sake, what would one do to correct low KH?

 

[Purrbox]

Dissolved CO2 will cause low pH readings, not what BlueRose is describing.

You can add baking soda with the water change water or use crushed coral to help raise the KH and buffer the pH. Unless you are trying to breed fish this probably won't be necessary.

 

[SpeedEuphoria]

Unless you are trying to breed fish this probably won't be necessary.

Well as long as its is stable

 

[bluerose]

I'm not sure if it's stable or not, I'll test every couple of days to see. If I get more fish this week it will probably be Friday so if the pH has changed much by then, I won't get them. It's gone down since my last PWC so... but then again I tested pretty shortly after the last PWC, not overnight like this one- so maybe the last test was a little off because it was registering the higher pH PWC mixing with the lower pH tank water still?

 

[jsoong]

Dissolved CO2 will cause low pH readings, not what BlueRose is describing.

I am stupid!!! I "know" that the pH was dropping, somehow I got it into my head that it was rising .... ignore that CO2 comment!!

Good catch Purr!

 

[bluerose]

Tested the tank. It's closer to 6.4 today. !

I've only had the tap water sitting out for a few hours but it's still testing a strong 7.6.

Gah! >.<

 

[OasisKeeper]

Tested the tank. It's closer to 6.4 today. !

I've only had the tap water sitting out for a few hours but it's still testing a strong 7.6.

Gah! >.<

Seems like your tap has some Kh, and that will always push it to mid 7's.

Seems like the Kh in your tank is exhausted or you are injecting CO2 ( if you are, I missed that comment).

Therefore, moderate PWC should put a bit of Kh into the tank and pull the PH up a bit (gently).

That would be my first pass and then check the results again.

 

[bluerose]

The odd thing is that after the PWC on Monday, it was lower than it was previously (low 6s before PWC, 5.8/6 day after PWC, 6.4 two days after PWC).

So the PWC appears to have immediately (within 24h at least) lowered it, and within the next 24h raised it... eh!

No, no CO2 injections. Low-light tank.

 

[OasisKeeper]

The odd thing is that after the PWC on Monday, it was lower than it was previously (low 6s before PWC, 5.8/6 day after PWC, 6.4 two days after PWC).

So the PWC appears to have immediately (within 24h at least) lowered it, and within the next 24h raised it... eh!

No, no CO2 injections. Low-light tank.

The only thing that comes to mind as an explanation is that the PWC is stirring up organics and causing a bacteria bloom. Or the test readings are inaccurate somehow. Commercial folks pay hundreds or even thousands of dollars for test kits and instruments but somehow we expect that our $15 tests should be 100% every time. Go figure.

I'd still try PWC again once or twice before I resorted to tossing in baking soda to pull it up. Or you could just keep checking and not worry as long as it is not swinging too much. Some people on forum would love to get your PH numbers.