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· Registered
2 Posts
Discussion Starter · #1 ·
Hi all,

I've just started out with my first reef tank which I've had for about 3 weeks. After using Denitrol to get the tank cycled, I added a couple of clowns a week later.

The fish themselves are doing fine, and the live rock I have in there is doing well also.

However, I keep testing the pH levels and they seem to have dipped to dangerously low levels (sometimes as low as 7.6). I've used a buffer which has picked it up temporarily, but they dip back down again after a day or so.

Does anyone know what could be causing this?

Thanks in advance.

· are friends
5,349 Posts
from what I've been reading recently it is fairly normal in a young tank. There may be excess CO2 in the tank from being young and still working through the initial cycling to establish the tank. Try adding a powerhead pointed up towards the surface to create more surface agitation or adding an airstone to help push the CO2 up and out. Sounds like once the tank is more established it will take care of itself.

I have a 10 gal nano been running a little over 2 months, the pH was running about 7.8 and I started dosing 8.4 trying to bring it up but was advised not to dose anything and just let it run its course. Now it is up to about 8.1 on its own, no dosing. Its a little more complicated due to having the clowns in it already, so find out what the clowns will tolerate (I think typically fish tolerate lower pH than corals, but you'd have to research what clowns can handle), if it dips below what the clows can tolerate then keep using the buffer to keep it up until it can handle it on its own, otherwise just let it run its course..

· Registered
2 Posts
Discussion Starter · #3 ·
That's reassuring - thanks for that. The clowns aren't showing any sign of stress so I'm not too worried about them for now.

I do have an aerator at the surface, but I'll get an air stone as well to try and speed things up.

· Registered
2,067 Posts
Everything in your tank uses O2. Since it is a new tank your biological filter is establishing itself. This bacteria will consume a lot of O2. Your drops are from the excess CO2 and the depletion of your O2. Several tips above will help. Powerheads for surface agitation, opening windows, running skimmer line to the outside and possibly an airstone will help. I would shy away from using buffer as it is just as you saw temporary. It masks the issue and does not fix the problem. Many stuggle with this issue. The best solution is time. The filter will balance when the tank gets more established.

I would also shy away from adding any other livestock until the tank gets in balance.

Welcome to TRT and best of luck with the new tank.

· Premium Member
4,738 Posts
hey and welcome to trt!

could you tell us a bit more about your system? what size tank? what kind of water are you using...tap, ro only, ro/di? what the filtration situation? how much/what kind rock/sand? what are your other params...ammonia, nitrite, nitrate, sg? what tests are you using? what do you have for water flow in the tank? what kind of tank do you want this to be, fish only or a reef?

have you found the reef keeping made easy thread yet? it is a long, but great read and will explain a bunch about the things that go on in our systems.

this is a prime example of why I am not a fan of these "quick cycle" bacteria in a bottle things. there are other things going on in a new tank besides the nitrogen cycle. new tanks have a lot of fluctuation in parameters and bacterial populations as they try to find the equilibrium point between enough nutrients and the number of bacteria. the pH drop you are seeing may be the result of a bacterial explosion, so to speak. the bacteria use up the o2 in the water and produce co2, thus dropping the pH. this swing will even out over time, but is not at all unusual in a newish tank. imo, if the pH is dipping below 7.8, I would return the fish until you get the issue sorted out. most likely it will stabilize nd come up in time. these quick cycle deals may take care of the nitrogen cycle, but there is much more going on in our tanks and it takes some time for everything to settle. the cycling period is also a great time to practice water changes and other maintenance routines and adjust your tanks equipment or layout before live things are introduced. this time is invaluable to anyone, but especially to a new person who may not have any "routines" down.

there are a couple quick tests you can do to kinda determine the cause. first, test the pH of the tank and record it. now, take a sample and let it sit in the room that the tank is in for about 5 or 10 minutes. maybe agitate it a little bit. now, test it and record. if the pH increases, it is probably low due to a bacterial explosion. if it doesn't increase, tak a sample outside and let it sit for 5 to 10 minutes. if it increases, there is an o2, problem in the tank and in the room. you should try to get some fresh air into the room and/or increase the surface agitation in the tank.

im not a big fan of buffers. I look at them as a band aid and not really addressing the underlying problem.

my tank was empty for 3 and a half months before I added my first fish. I spent that time adjusting waterflow, tweaking rock placement, and familiarizing myself with the routine things so I was set to go when I had lives depending on me! I think the bacteria in a bottle products are robbing a lot of new people of this opportunity, as well as the 30 or 40 bucks that it costs!

· Registered
253 Posts
Same problem - Different result

I also had this same problem which I posted in another forum on June 26th

Lost my Pink margin fairy wrasse and my tomini tang in my 29 gallon biocube quarantine last night. Same ole story - they fed fine last night and this morning both were gone (they were the only inhabitants in the 29 gallon). I noticed the tomini was breathing fast last night around lights out but didn't pay it alot of mind since I have no expereience with tangs and whether it was normal behavoir or a sign of distress.

The biocube was previosly used to quarantine a bellus angel and 4 neon goby. Prazipro has been added 3 times in total to the tank (over the course of two months) and copper was added once for the last quarantine. In between that time and the addition of the new fish - I ran carbon in the filter basket for a week.

Some general parameters of the biocube: 29 gallon, runing as many ceramic biomedia balls in the refugium area as I can fit. Been running since March I beleive. PVC pipe is used in the display for hiding. I have a spectrapure autotopoff. I control and monitor everything with a neptune apex lite, one mp10 running between 80% to 85% power with night mode running @ 40%, one ecotech radion for lighting. I run the biocube without the glass cover to maximize oxygen exchange. The return to the display has one of those whirlybird flow diverters so that the surface is agitated every time it spins around.

Some general observations of the biocube:
I noticed when the bellus was in the tank, she loved to gulp air. I thought she might just be playing but it may also mean I have a dissolved oxygen problem in the tank.
The biocube has always grown algae on the glass so I do have nitrates / nitrates. I didn't really test it though. I no longer own an ammonia test kit. However, I like to think I could detect ammonia just through the smell of the tank. Our noses can detect scents much more accutely than a test kit. A test kit would only quantify it for us.
After adding the ecotech radion light over 2 months ago - the temp is stable at 78 degrees. The pH used to be stable - fluctating between 7.8 and 8.1 throughout the day (see the attached graph).

6/15: Bought the fish from Faois. Acclimated via drip for an hour and introduced them.
6/15 - 6/22
Fed them the entire week - small shot of brine in the morning (maybe 10-15 total brine in the tank - probably less than that), 1 small autofeed of pellets/Flake around noon, 1 small shot of mysis in the evening (again no more than 10-15 mysis - again - probably less than that). I also rubber banded some nori to a rock for the tang to munch on.
During this time too - I noticed how big the poops were the tomini was taking. holy cow! it was like a quarter inch in diameter and about an inch long. He musta been proud haha.
  • 5 gallon water change (with Red Sea Coral pro).
  • Replaced the filter in the media basket - this may have been my downfall.
  • Removed the carbon from the media basket
  • Dosed 7 ml of Prazi Pro
between 6/23 and 6/24 when I would replace the nori on the rock, I noticed the rock did smell of ammonia. I think this may not be the best idea and should probably stick to feeding nori on a clip or screen instead to allow water flow to penetrate it.

6/24: after re-aquascaping my display to support the addition of a piece of rock from the sump - I took some of the macro algae from that rock and put it on a clip in the quarantine. It may have contained pods and a few Strombus grazers. but it was a small piece.

6/25 Business as usual

6/26 morning - they were dead.

So my possible causes:
a severe drop in dissolved oxygen
An ammonia build up that I didn't detect
The death of one of the fish (especially the big tang) may have spiked the ammonia - causing the other fish to kick the bucket.

I did replace the filter that I have had running in the biocube for these past 4 months. I beleive this filter was covered in the bacteria that was keeping my tank stable. When i removed it, I lost the fish. The ceramic biomedia balls also helped with the stability of the tank but in a lesser degree. I think the tang might have been too much to handle for the 29 gallon biocube.

As you can see from the below pH measurements (in the 6_26 pH graph)over the last 7 days - I had a problem I didn't know about. pH is currently 7.1 - much too low. Whether this is from Ammonia / Nitric Acid / low dissolved oxygen - this is what caused the fish death.

Come to today (please see the 28_Jun_2013 pH Graph)
Installed an airstone in the return well.
Put some chaeto into the refugium with a light set to run 24x7
Fired up the AquaticLife Mini Protein Skimmer in the first well.
Added more of the ceramic balls.

my pH shot up over the night by 0.3 to 7.5 (which is closer to the trough period with lights out before this whole fiasco started).

Of course there is no load on the system - no fish no feeding. But I'm starting to feel a little better.


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