PH Crash & Ammonia Spike Fish Fine??

bbarron88

Registered Member
Aug 22, 2008
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Hello. I have been a live plant/Discus aquarium hobbyist for 20 years. I recently bought a 125 gallon acrylic with built in wet/dry filter (in the back of the tank). I set it up for cycling 5 weeks ago. I followed my normal cycle procedures, adding a few plants, two Amazon swords, three small Anubius, and a piece of driftwood with java moss growing on it. I also added 15 Rasbora Hex. I watched the cycle for the first three weeks, and saw the normal levels (ammonia raised, then began dropping, nitrites began to raise, then finally nitrates). The cycle seemed to finish about the third week mark ammonia 0, ph 6.5, nitrites and nitrates 0.0.


I then added 50 cardinals, 15 panda cory cats, and 5 Dwarf Blue Rams. Everything was very healthy and happy. About a week later (at the four week mark) I added 10 small discus and three more amazon sword plants, a couple of hygro, and four java fern. Everything still seemed to be happy and healthy. Water crystal clear, plants growing, fish happy and eating all week.


At the beginning of the 5th week, I did a scheduled 25% water change (straight water change, not disturbing the gravel). I prune the dead leaves and remove dying plant matter at bottom of tank. then just suck water out and water in. I've found that in the past this works very well. Every other month I do a light gravel vacuum with the water change....Anyways, the next morning after doing the water change, the water was cloudier than usual. I thought it would go away after a day or so, figuring it was just the introduction of the new water. Well, it just kept getting cloudier and cloudier by the hour. I tested the water and the ammonia was 8+ YIKES.
At first I thought the test kit was bad, because all of the fish were doing great, even the Discus. So I bought another test kit. Still tested 8.0 ammonia. I checked the PH and it was bright yellow, seemed to be lower than 6.0. This alarmed me because I always keep it at about 6.8. My tap water is 7.5 and the driftwood brings it down to about 6.8. This is the way I've always done my discus/plant tanks for the past 20 years with no problem. This tank seemed to be following the same track, until this ammonia problem.


So I did a 50% water change and cleaned the filter sponges and replaced the strainer pad. Added Ammolock, Prime, and StressCoat. The PH and Ammonia were back to normal (levels 6.8 and .5). The water was also a little clearer. The next morning the levels were back to dangerous, but the fish were all doing fine. So, I did another 50% water change. Levels returned to normal and water began clearing up. The next day the water was still clear, fish all still doing fine, but ammonia back up to 8+ and ph back down below 6.0.


I started talking to various tropical fish store owners in the area, research online, and reading some old plant/discus fish books I have. This all led me to believe I had a PH crash going on. I suspected that the introduction to a large volume of fish and plants at one time caused an ammonia spike and acid production caused a ph crash. Figuring the ph crash killed off a lot of the biological bacteria, I did another 50% water change and added the alloted amount of Safestart (supposed to be nitrosomonoas and and nitrobacters). They guarantee the tank to be ready to stock with fish after adding this. I hoped that this would replace any of the bacteria that died from the ph crash. I also added some Neutral regulator 7.0 from Seachem. This has seemed to help as the ph doesn't drop overnight, but it is still going down below 6.5 and the ammonia is back to 8+...


All the while the fish are doing great!!! I have stopped the water changes after adding the safestart thinking that the tank may need to go through another cycle with this new added bacteria. Its been a couple of days now and the water is crystal clear, all fish and plants still doing great. I've cut down my feeding and remove any dead leaves as I see them. But the levels are not changing. Ammonia still 8+ ph going to the 6.0 mark 0 nitrites and 0 nitrates.


So at this point I'm not sure if I should continue with the water changes or just leave the tank alone for a couple of weeks and let it balance out. There is something driving the PH down abnormally fast in relation to my past tanks, and the ph buffer does not seem to be working all that well. The thing that is weird is that the fish are all fine. No deaths whatsoever. I'm guessing not to worry about the ammonia because of the ammolock. But I'm worried that another ph crash will kill my biological bacteria and that I may come home to a dead tank one day.. Yet everyday, the fish are happy and healthy.


Some people say I should continue doing at least 25% water changes daily until pH stabilizes and continue using ammolock until ammonia levels come down. Others say I should leave the tank alone and let it go through its normal cycle process, because it is really not finished cycling, possibly the water changes are causing prolonged cycling process.
So I don’t know if the fish are doing well because I’ve been doing the water changes, or despite them.


I was wondering what you all thought about this situation. Any suggestions or ideas? Leave it alone? Continue water changing? Add coral? Remove some fish? Add anything else to the aquarium?
 
What is the kH of your water and have you tested your regular tap water for ammonia?

Are your plants healthy and growing? Healthy plants act as an ammonia sink, add more if your setup is sustaining growth.
 
Well, this is very strange....

First of all, my guess is the prime and the ammonialock have locked up the ammonia. We've discussed safestart on here many times and most of us agree that it's bunk.

Second of all, water changes do not affect the process of cycling-this is an old myth. Bacteria resides on the objects in and surfaces of the aquarium, though most of it is in your filter. The amount in the water column is minimal. Usually in this case, we recommend changing the water until the ammonia is below .25 and using prime.

Third of all, I would check your KH immediately. It sounds as if it is in bad need of a buffer. Not chemical buffers-crushed coral, for instance. Chemical buffers can actually be bad for your fish.

Fourth, what type of test kit are you using? Strips are basically useless.
 
I have strips and API liquid test kits. KH is 40 and GH is 180.

Last night I did another 50% water change and took apart the wet dry filter media, leaving the bio balls alone. I made a startling discovery. The powerhead had dead plant matter and some fish carcases in it. I cleaned all of that out and tested again this am and the ph is back up to 6.6 and the ammonia down to .5. I think this was causing the problem.

I'll keep you all posted.
 
With pH below 6.0, ammonia could rise to quite astronomical levels without harming the fish, since vanishingly small quantities would be present in the NH3 form; it would nearly all be NH4+. The danger is only in raising pH too quickly (remember that above around 5.0 the pH doesn't bother the fish, despite common "wisdom") is that the NH4+ turns to NH3 and causes rapid mortality.
 
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