PH too low

67chevelle

67chevelle

Basset Hound
Jul 30, 2008
2,286
2
38
I have a pressurized CO2 tank that I switched out a Red Sea reactor,http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=15524for a glass diffuser http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=9915 , I made the switch last Wednesday,and everything seemed fine.When I got home from work yesterday and today,there were no bubbles coming out of the diffuser, so I cranked open the needle valve to get them going,then turned it back down to the normal flow rate,this takes less than 5 seconds.I am thinking I need to add a back flow preventer to stop water from siphoning into the CO2 tube,stopping to CO2 gas from getting into the diffuser,but I am not sure about that(should I??).The CO2 has a solenoid valve on a timer with the lights.

Anyway,about 5 minutes after I got the bubbles going tonight,I added some Excel,and regular Flourish.A few minutes later,the fish started to gasp at the top of the tank.After another couple minutes, they were all laying at the bottom,and a few were swimming upside down.I checked ammonia and nitrites,both 0ppm.Nitrates were 10ppm.The PH was either 6 or lower,as that is as low as the API test kit goes( i think it was lower).This is lower than I have ever seen it in this tank.I did 2, 75% water changes and that raised the PH to around 6.4,which is where it is usually at.I also added some Excel,and some regular Flourish again.The fish immediately started to swim at the top of the tank again,then at the bottom again.2 of the glow light tetras died.I changed another 75% of the water,did not add anything but dechlorinator,shut off the CO2,and removed the filter pads.Everything seems fine now.All of this happened within an hour.It's 5 hours later,and everything seems fine.

So does anyone think the problems with the fish have to do with the CO2,or adding ferts?I got some new plant stems,so I have been adding ferts daily,trying to get the plants to grow faster,which it has done.I have been adding ferts daily for like 3 weeks now.The tank has 3.2 WPG,it's only a 10 gallon,so I don't think the WPG really applies though.I am at a loss as to what exactly triggered the weird behavior,and some very fast deaths to the fish in the tank.It had 10 glowlight tetra( 8 now),2 male guppies,and who knows how many RCS,at least 50.The RCS acted weird as well,swimming upside down.
Any ideas????
 
Last edited:
We have similar setups. Im running a 10 gallon with pressurized CO2, my pH is below 6, and Im at 4wpg. You could try adding some baking soda or something to raise the kH and dH to act as a buffer and prevent the pH from dipping so low with your CO2. It's the CO2 that's lowering the pH, not your ferts. From your fish's behavior though, it sounds like they were suffocating. Do you have a drop checker?
 
Yup I have a drop checker,it's always green,except for the 2 days this week that it did not get going until I got home.The thing that has me concerned is that the fish where fine until I got the CO2 going yesterday,and added the ferts.The problems with the fish started immediately as I was turning up the needle valve and adding the ferts.I have never seen anything like it.They literally went from acting fine to gasping for air at the top of the tank in 30 seconds.
 
67chevelle said:
...so I cranked open the needle valve to get them going,then turned it back down to the normal flow rate,this takes less than 5 seconds....
about 5 minutes after I got the bubbles going tonight,I added some Excel,and regular Flourish.
The PH was either 6 or lower,as that is as low as the API test kit goes( i think it was lower).This is lower than I have ever seen it in this tank.
I did 2, 75% water changes and that raised the PH to around 6.4,which is where it is usually at.I also added some Excel,
The fish immediately started to swim at the top of the tank again,then at the bottom again.2 of the glow light tetras died.I changed another 75% of the water,did not add anything but dechlorinator,shut off the CO2,and removed the filter pads.Everything seems fine now.All of this happened within an hour.It's 5 hours later,and everything seems fine.
Click to expand...

I don't have any experience with pressurized CO2 or Excel. But cranking open the valve for 5 seconds on a 10g tank, sounds like alot. Then on top of that, adding Excel.

CO2 lowers pH. So like you saw. It went way down from the two being mixed.
If you happened to have looked at the drop checker when you got home, and it was green. Then, maybe, CO2 was being added most of the time you were gone? And stopped before you came home.

Typically, tap water is low in Oxygen. So you did get rid of the CO2 when you done the first change. But the oxygen lvl would have been low. Now you done a second change. That basically kept it low or possibley made it a little lower.
Now adding Excel, just raised the CO2 lvl again. So between low oxygen lvls and adding Excel. Its pretty much like FrostyNYC said. The fish are suffocating.

Then back to the water change, and back to low Oxygen. But no Excel(CO2) and things are looking better.

Thats how I see what happened during the events.

And yes, get a Check Valve.

 
Nope.It's either blue when the CO2 is off,or green when it is on.Never seen it yellow.
 
SMinNC said:
Those drop checkers take a while to react. I think everything happened too fast for it to have a chance to go yellow.
Click to expand...

Exactly. I have used drop checkers before and had 2 suffocating incidents in my tank without them every turning yellow. I have had them blue with tremendous plant growth. I threw them all away and don't even rely on them anymore. I rely on the ph/kh chart. I keep my kh at 10 and my ph at 7.2. No problems whatsoever and it allows for some mistakes that aren't deadly. With a ph of 6.4 from CO2 introduction, things can get deadly pretty quick if there is just a slight addition of kh.

At 7.2 ph I can go from 10.0 kh to 13.0 kh without any danger with 28 ppm CO2. Likewise, the KH can drop to 7.0 and I will have 15ppm CO2.

With a 6.0 ph, you have 15ppm at 0.5 kh and 30ppm at 1.0 kh. At 6.4 ph you have 12ppm at 1.0 kh, 24ppm at 2.0 kh, and 30ppm at 2.5 kh.

From what I am reading from the OP, it sounds like there was just way too much CO2 in the water. As always, make gradual changes. Cranking up the CO2 and then throwing in ferts is probably not a good idea for the fish. Plus, the plants really are not going to notice if the CO2 goes up gradually and the ferts are put in gradually. I use ferts 3 times a week at most, and that works just fine. Why change a good routine and mess with everything if everything is fine in the tank? If plants are growing in it, new stems should grow just fine too if they were healthy when you received them. Personally, I would rather lose some plants and/or have slower plant growth than risk killing every fish and invertebrate in my tanks.
 
What's in the drop checker? Is it 4KH made up from DISTILLED water? If it's not, then it can be offset one way or another.
 
You must log in or register to reply here.
AquariaCentral.com
Top Bottom