Not An Emergency Yet, But..... With This Level Of Consistent Ph Droppi

[simonero]

I have a 55gal freshwater aquarium.  Recently the pH dropped from ~neutral to ~6.4.   Got worried, bought some supplies, went on chat to discuss it.
 
Within just a couple days, it is now down to 6.0.  This is frightening, because I added a bubble stone and half a cup of aragonite sand (in a whisper filter I had space for, so extra filtration as well).
 
I haven't gotten a kH test kit yet because I'm in the midst of mid-terms and just don't have time to brave my city's traffic yet.  But I absolutely will be getting one ASAP.
 
In the meantime, should I be worried?  Why is this happening?
 
Could the fact my plants are growing better (one side has a light with frequencies beneficial to plant growth) be a major player in this issue?  Also, there's a piece of wood in there.  I'd hate to remove it - it's what finally made a previously very stressed fish happy - but if this low of a pH is an "emergency" I could do that in theory, until I come up with a better solution...
 
Thoughts as to:
(1) why it is continuing to drop despite my taking measures to increase the kH (I have reason to suspect low kH)
(2) whether or not I should do anything NOW, such as switching out my plant light or removing my wood
(3) what will really happen with my pH this low?  How quickly will it be a big problem?  Do I have another week to wait without it hurting my fish?
 
Other notes: outgassed tap pH is 8.4.  No ammonia or nitrites.  Gave up trying to accurately measure nitrate, my API kit says the same thing every time regardless of tank and I don't believe it.  No protein on the surface.  I have a 75gal aqueon filter on my 55, one of the filters is pretty new (I made sure to let it build up first) and the other is ready for a change once the newer one has sufficiently built up more bacteria.   I also always have extra charcoal in there for good measure.
 
Opinions/help greatly appreciated!  I'm so worried!  I've never had my pH go this low before, and everything else in the tank seems to be going to perfectly - it's so misleading...

 

[DrRob]

pH of 6.0 isn't a disaster. I've got a tank running around that level and we have members with lower levels. Filter bacteria can start to suffer if it drops too far below that though, so do keep a north eye on things.
 
Do you happen to know if your tap water is regarded as hard or soft? Soft water can still be alkaline when it comes out of the tap but will acidify very easily with simple things like pieces of wood.
 
Knowing your stocking would help a little, as some fish will relish that pH, others will be less impressed.
 
Personally, I'd do nothing NOW, but getting a handle on how soft/hard the water is would be useful, even if just the local supply (and your LFS may know this if they're close enough to be on the same supply).

 

[Byron]

Agree.  And perhaps I can explain a bit, as this is something I have dealt with for more than 25 years.
 
We need to know the GH and KH of your tap water.  You should be able to get this data from your municipal water board, maybe on their website.  Once you know the numbers, things are not likely to change in the aquarium unless you target GH/KH, and aragonite does this.
 
Once an aquarium is established, which can be roughly two months or longer after set-up, the natural biological processes will tend to acidify the water and the pH will lower.  The breakdown of organics by bacteria is the prime operator here.  Regular water changes and substrate cleaning work to keep things in check.  But before you jump into this in a big way, there are other factors to consider.  The type of fish as Rob said is significant; and you have plants, and a major source of plant nutrients (and particularly CO2) comes from the organics in the substrate.  Organic matter such as wood, dry leaves, and peat also release acids as they break down.  In my experience, wood is very slow at this, so your piece of wood is almost certainly not a prime player here.
 
To the question of the aragonite.  Again, we need to know the initial GH and KH (the latter "buffers" pH) and fish load to better grasp the situation.  But a small amount of aragonite may not do much.  However, you can quickly cause the opposite effect, so I would not go adding more just yet (you may not need to anyway, depending upon the fish).  In my 115g tank, I added just three tablespoons of aragonite to the filter, and the pH shot up from 6.2 to 7.6 overnight.  I have zero KH in my tanks, so this targeting had free reign.  Years ago I used dolomite the same way, and maintained a pH of 6.4 (water was below 5 then).  One has to be careful making these changes.
 
On the tap water pH, it is possible the water board adds something to raise the pH.  This is common in areas with naturally soft water, and an acidic pH can corrode water mains and plumbing.  Where I live, soda ash (sodium carbonate) is used to raise the pH from below 5 up to around 7.  This fairly quickly dissipates out in the aquarium, so my tanks remain stable around 6.2 to 6.6 even with 50% water changes weekly.  Some areas also use lime (calcium hydroxide) for this purpose.  You should find out from your board if anything similar is being done.
 
I presently have seven planted tanks and the pH ranges from lows below 5 (cannot measure below 5 so no idea what they may be) in three to the highest at 6.4, and I have all soft water fish, many wild caught, so this is ideal with my zero GH.  Obviously, as Rob said, it is no problem with suitable fish.
 
Byron.

 

[simonero]

First of all, thank you guys!!!!!
 
And ok, I have finally located the information about my area's water (no idea why it was so hard to find!)..  It says they checked from Jan-Dec 2013, almost 400 samples.  However for GH it was only tested once.  (I want to get kits to test my own water but because that has to wait until I have time, this will have to do...)
 
My KH is reported as 54.9mg/L, with a 40-60 range.  So pretty low?
My GH is reported as 72.  This is consistent with most other info I've been able to gleam about my area; that the water isn't very hard.
The pH is reported as 7.22 with a range of 7.0-7.7.  That is what I read initially when testing myself.  However, after outgassing, it was more like 8-8+.  I forget the exact #.
 
I have 2 angelfish (8-9 months old to give you a size idea), BGK, and a columbian shark cat.
 
(Yes, I know the cat needs a new home.  Had one lined up when I got him and it fell through.  Still looking.  He seems 100% fine though, as far as visual behavior.  Also, yes I know BGK and cat get big.  They are definitely not too big right now!  I promise!)
 
I did a little research.... from my findings, fish that prefer hard water use up more resources, and the catfish falls into this category.  Does this make sense?  Could he be having an effect on my water as well, or is that probably irrelevant?
 
Lastly, tested my water last night and it is still right at 6.0 - or lower if that's possible, it's at the very bottom of my color chart that came with my API test kit.

 

[Byron]

First off, the Columbian Shark Catfish, which I assume is the species Ariopsis seemanni, needs attention.  Young juveniles can manage in fresh water, but as they grow they need marine salt (not common salt) and are best in brackish or even fully marine tanks.  And a fairly large tank, for a fish that attains more than a foot and is needful of good space for active swimming.  Read more here:
http/www.seriouslyfish.com/species/ariopsis-seemanni/
 
The angelfish and BGK are fine in your soft acidic water.  [You certainly do not want salt in with these.]  So having removed the Columbian, you are fine with your water parameters.  The BGK needs at tank no less than six feet long and two feet width (front to back), so unless this is going to be feasible within the next few months, I would re-home the BGK.
 
To the water parameters.  GH of 72 ppm (= 4 dGH) is soft to very soft.  Actually excellent for soft water fish, as the GH should be just sufficient for plants like swords which would be ideal with the named fish.  I have zero GH and have to add Equilibrium to raise it to 4 or 5 dGH solely for these plants.
 
The KH at 55 ppm (= 3 dKH) is low and this probably explains why the pH is lowering like it is.  Again, with the soft water fish, this is not going to be a  problem.  At this point, I would not mess with the aragonite or anything similar, as there simply is no need.  [Obviously, the Columbian is another story as I've already set out.]  But, out of curiosity I would wonder what level your GH/KH might be in the tank with the aragonite.
 
The theory that fish will use minerals from the water is certainly true as far as using minerals, just the same as my plants use the hard minerals from the supplements I use to raise the GH.  But the plants' use is so minimal I see no difference with an API GH test kit after a full week, and I would suspect much the same for fish.  But I would not argue this with an ichthyologist.

 

[simonero]

Byron, thank you again for the response!
 
As far as the Columbian is concerned - unfortunately (though I love him) he isn't going anywhere any time soon.  When I got him, I had a set plan.  The person who was going to take him is no longer with us.  I have tried extremely hard to re-home him.  My only options, until something comes up, are to keep him and make sure he has tank structure, friendly tank mates, and a proper diet... or give him to Petco to store in a 10gal with no structure (i.e. all their tanks) then sell as a freshwater fish to someone who knows and cares less.  

  So until he outgrows the tank (which he has not yet; BGK is fine too, he doesn't grow fast) or I can visit my old city (and therefore LFS, where they can both accommodate and sell him) he stays.
 
Given that, do you think he would use up a substantial amount of nutrients because harder water is ideal for him?  And do you still think I should not be worried about my pH?  Even though I can't make the tank perfect for everybody because the salt, I'd like to make it as close as possible otherwise...  and I'd really love to give my fish another piece of wood, the one I gave them seemed to make a significant positive difference in their behavior.  They love it.
 
The pH with half a cup of aragonite is 6.0.  It's been in there since Saturday.

 

[Byron]

The aragonite is fine then.  This will last years before it needs replacing.
 
I really can't offer much on the fish issue beyond what I have mentioned.  This is not going to work, and may be causing issues already.  Fish develop and grow all their lives, and it is a dual process.  The external physical size increases, and independently the internal organs develop.  The internal continues even if the external is prevented by space or water, and this causes serious issues for the fish that can go completely un-noticed until it is too late.  Stunting can result.  There is also the issue of the quiet nature of angelfish and BGK fish, opposite to the vigorous activity of the Columbian, and this will likely be trouble down the road for the quiet fish.  All these things cause stress, and this weakens the fish's physiology.  There is a lot to fish compatibility.
 
Byron.

 

[DrRob]

I agree, I can't see any way in which that stocking can have a happy middle ground, ultimately the tank size and water conditions will cause the Columbian to succumb, but it may well take the others out in the meantime as it's a far more aggressive fish than they'll be able to handle.

 

[simonero]

Both,
 
I fully agree about the size (soon - he's OK for now but he is growing quickly) and water with my Columbian.  I promise you that I am concerned about these issues and am actively looking to re-home him.  It is bizarre to me that I'm having so much trouble giving him away!  

 A Marine Bio program at a neighboring university declined my offer for a free fish, and the only response to my many ads in multiple different places was along the lines of "Do you still have the catfish can I put him in my pond."  (I gave him a small earful...)  And one person who just wanted to let me know how nice it was that I care about my fish...  This is why I am going about things the way I am for the time being.
 
The temperaments are actually not what you'd think.  (I suppose I got lucky).  It's really quite surprising and interesting!  I got the Columbian and BGK at the same time over a year ago, and they are basically inseparable.  Despite the option to do otherwise (other territories each likes as well), they still spend a significant amount of time together.  The only way to describe it visually is that it literally looks like they are cuddling.  Other than the day I bought them, they have never shown an ounce of aggression towards each other (or any other fish).  I specifically try feed the BGK individually/first because he is so blind, but I've noticed the Columbian will always wait to scavenge until the BGK is done.  I am extremely curious if it's possible that they have socially bonded in some way, because logic indicates they should be competitors for everything BGK eats, but I lack the expertise and am aware I could be anthropomorphizing because academically I study human behavior...   The angels on the other hand are extremely aggressive.  Have killed almost everything they could.  But, not once have they bothered the BGK/cat.  And the remaining 2 have this friendly alpha/beta thing going on.
 
Sorry for the somewhat irrelevant story, I just find it interesting...  I do have stress observations to compare to for these fish (earlier tanks/times), and I can't see any current indications of stress (at this point).  

 

[Byron]

Angelfish and black ghost knifefish actually do quite well together.  They have near-identical needs, meaning water parameters, dim lighting (very dim).  Main issue here is the tank is not sufficient for the BGK to properly develop, and this begins very early.
 
Fish stress is not always visible to us.  The allomones these fish are releasing into the water are chemical signals read by other fish, and these can cause stress as much as any actual physical interaction.  The Columbian may well be stressed from the water and thus not behaving normally.  Neither you nor I can tell in all cases.  But when fish behave differently from the "normal" as appears to be occurring here, that alone is a sign that not all is OK.
 
Have you any responsible fish stores locally that might take the Columbian?  I don't know what else to suggest...have you tried returning it to wherever you acquired it?
 
I have a "rule" I gave myself several years ago after I acquired a fish that quickly proved to be unsuitable, and I have seven tanks so plenty of options normally.  I will never acquire a fish for which I do not know its origin, habitat, requirements (water, tank aquascape, numbers) and temperament; and for which I do not now have a tank of sufficient size to house it for its full life.
 
Byron.

 

[simonero]

How are my fish behaving differently than normal?  I didn't mean to express that, and would like to correct myself if I unintentionally did.  For these fish, that is normal.  When they were both an inch long, bought together, and both belonged in freshwater, they did the same thing.  I just thought that the dynamic was unusual and not what I would expect.  But it is consistent with their previous behavior and their general temperament.
 
That said I understand your point about what is not visible.  And I don't know anything about allomones, but I'll be sure to do some research!  Thank you for clueing me into something I didn't even know I was lacking knowledge about!
 
The LFS I bought him from is in another state.  No, there are no responsible fish stores that I can find.  Not for freshwater/brackish.  I've called every fish store within 45min of where I live.  When I called the one everybody told me is the "place I should call", and I asked if they sold brackish fish, she asked me what "brackish" meant.  There is a Petco with 10gal tanks and the same set up in every tank which is considered to be the best tropical fish store in town, and a Petsmart with no employees who know anything about fish.  I ended up teaching the employee stationed near fish about angelfish basics because the decal had very misleading info, and he was like "Wow!  That makes so much more sense!".....  So this is what I'm working with lol.
 
Yea, I've learned my lesson....  The BGK was an irresponsible, impulse buy (LFS guy showed me a full sized one; the tiny baby was so so cute; I walked out with a new fish.  Went home.  Looked him up.  Texted my boyfriend that I was accepting his previous offer for a free, bigger tank and needed it ASAP).  And like I said I was only planning to keep the catfish temporarily - my boyfriend ran a university biology department capable of housing him even if a tank had to be set up.  But, I won't ever buy a fish that way again either.  That was over a year ago.  I haven't actually bought any fish since.  The angels were a gift from a roommate, so I'm lucky that is still working out!