PH Steady 6.0 in tank need HELP!!

J

jmarble

Registered Member
Oct 13, 2005
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I have a 120 Gal tank running for about a year now the PH was steady at 6.8 - 7.0, but recently my PH began dropping to low levels.
Here are my current readings:
ppm (mg/L)
NO3 = 20
NO2 = 0
GH = 150
KH = 40
pH = 6.0 or possibly lower

I have added a new Lava rock. I have two PowerHead 301 without a undergravel filter. I have the flow of water pointed up to make ripples in the water to increase oxygen levels. I have an Emperor 400 and a AquaClear 110 Power Filter. I recently changed the sponge media in the AquaClear and also switched from the white ammonia stage 2 media to activated carbon. I change my Emperor carbon filters monthly and do a 25% water change every two weeks. I have 3/4 inch gravel in the bottom I clean Bi-weekly with water change. I purchased a pH test kit to double check my readings and it confirms my findings. I tried raising it with PH up one time and the pH raised, but after a few days returned to 6.0. I read to try crushed coral or limestone, but I want to diag the cause. Any help is appreciated.
 
Most likely your cause is your water has a low pH to begin with. Using crushed coral or some kind of calicum will buffer the water and help stabilize and raise the pH. Just be careful to do it slowly.
 
if youre fish looks okay then i say jsut leave it as is. i know this person that breeds apisto and he keeps his ph between 4.5~5.5 and his apistos have the nicest color ive ever seen.
 
I'd have to agree with that. Messing with the pH will most likly cause more problems then you originally had.
 
Did you test the tap after it sat out overnight. It will probably be higher than 7.0. If not that would be a big part of your issue (little or No buffer in tap water)

and also switched from the white ammonia stage 2 media to activated carbon.
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The biological process of the bacteria converting ammonia and nitrites uses Kh. So tanks naturally drop over time if water changes aren't done regularly with a water source that contains a decent level of KH. Since you recently switched out chemical media to a type that does not adsorb Ammonia, the biological activity has Probably increased somewhat in your tank. Since you were starting out with almost no KH and you potentially increased Kh consumption your system is not stable.

Your tap is most likely low KH but it will be easier to tell with a KH test kit, and or a pH reading after sitting out. You are doing small water changes bi-weekly so even if the tap has a good bit of KH it may not be enough to compensate for consumption.

Was the tank naturally 6.8-7.0 or was something added to make it that low?
Please verify the Tap water after it sits out and let us know.
Also if you can get a KH test kit and test tap and tank that will help.

If tap Kh is low then To remedy the situation, crushed coral, aragonite, or lime can be added to the sytem to counteract the KH consumption. Either way You will want to make changes slowly (Low volume high frequency water changes) as your tank is most likely far different than Tap at this point. Once you get the tank and tap in the same realm then you can do larger water changes less frequently. How much how often is not a set science, but I usually reccomend 10-15% a couple times a day until the tank comes back to similar parrameters as the tap. Once tank and tap are the same then I'd start with weekly 50%. Adding crushed coral to the sytem will give you a canstant release of Carrbonate, and once you find the ideal amount then it will counteract consumption of KH between water changes.
As far as PH up, it is usually just baking Soda packaged to command a higher price. Baking soda will work, but you need to be careful adding it directly to your tank as it changes things very rapidly. When you added pH up the tank was already starved for buffer. You didn't bring the levels up very high, so the buffer you added was consumed in a matter of a couple of days and the pH dropped again. Once you get a steady level of Kh and maintain it then the tank will stabilize unless you skip maintenance.

For me I like to have my Kh at 2-3 dKH minimum. This will put the pH in the range of 7.4-7.8 which is about right for a stable tank. If for some reason you chose to keep it lower, then you will wnat to watch levels closely until you have estabilished a maintenance routine that keeps things steady at all times.
Dave
 
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misopeenut said:
if youre fish looks okay then i say jsut leave it as is. i know this person that breeds apisto and he keeps his ph between 4.5~5.5 and his apistos have the nicest color ive ever seen.
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well his biofilter won't live in that ph range.
 
well his biofilter won't live in that ph range.
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I've read about the decrease in bio-filtration at lower ph (only hobbiest literature, not scientific) and to be honest, I'm on the fence about it. People who keep hard to spawn, wild-caught apistos regularly keep their fish in 100% RO (nothing added back), and use simple sponge filters and peat extract to lower the ph into the low 5s. thier fish grow, thrive, and spawn. Thier ammonia, and nitrite remain at 0. Most do weekly water changes, but not all.
With NO biofiltration, even large weekly water changes cannot account for 0 ammonia/ 0nitrites. To add to this, nitrates are being produced in these tanks (this would rule out the possibility that ALL of the ammonia was being locked up as ammonium, which happens at low ph). Clearly some bio-filtration is occuring. Certainly not as much as what happens at normal ph levels, but some none the less. Bacteria are pretty adaptive. I would not be surprised at all if low ph tanks have strains of bacteria that have evolved to function at lower than optimal ph.
I myself have a 10g running as described above. It has about 7inches of apistos in it (not overstocked, but not way understocked either). The ph is below 6.0 (no idea how far below since hobbiest test kits don't go any lower than that). The fish are healthy happy, and even spawned for me about two weeks ago (eggs eaten grumble grumble). Anyway, just giving my take on the low ph / bio-filter debate.
 
I seriously doubt that the biofilter would suffer in low pH. I just can't see it as plausible.

If your pH is 6, then certain fish might be thrilled with it. I have blackwater tanks and the idea of that pH sounds very appealing to me. If you're keeping acid-loving species, you should actually consider yourself blessed. And the majority of the popular tropicals are acid loving after all.
 
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