saved a tankful of fish last night

[Andrewtfw]

My neighbor has a 37 gallon planted set-up that I assembled for her a couple years back. The other day the co2 regulator was not "regulating" well, so I turned it way down and told her to order another one. Yesterday she came home to find her rasboras and kribensis gasping at the surface and her plecos, loaches and cories on their backs on the bottom. All were breathing hard, but they were breathing.

Even though I turned the regulator down to what was less than one bubble per second, it somehow increased the flow of co2 the following day. The tank went from a ph of 7.2 and Kh of 5 to a ph of 5 and a kh of zero. I brought over a very large air pump and hooked it to the tank. I added small amounts of alkaline buffer but all it did was raise the kh. So I removed three gallons of water (I would have done more, but this was at 12am), and replaced it with slightly cooler, tap water that was treated with Prime. I was able to get the ph up to 6.5 with a Kh of 4. I wanted to keep the Ph under 7 in case the crash killed bacteria and causes an ammonia spike.

Soon after, the loaches (who we were convinced were going to die), flipped over and swam under the wood. The rasbora dropped to the mid levels of the tank and the kribensis returned to the lower area of the tank. The plecos began moving around, as did the cories. I could not be more pleased. I did warn my neighbor that the shock to to the fish may result in some die off in the next few days, but I am hopeful that this does not happen. Needless to say, the co2 is unplugged and disconnected from the tank until the new regulator arrives.

Sometimes timing is everything.

 

[rsretep]

i had same problem once with high co2 levels
similar resolution ...i added airstone and within an hour or so all fish were semi normal i lost a few rummy nose tets but all other fish survived...man that was scary

 

[msjinkzd]

good save!

 

[chris_todd]

While this could be the regulator, needle valve, or some other component in the CO2 system, this sounds a lot like end of tank dump... Is there any CO2 left in the tank?

Whatever the cause, good save!

 

[Tony]

Yeah, I fried a bunch of rainbow fish that way about 6-8 years ago. First setup the CO2 and didn't have a pH monitor at the time. Broke my heart, but it was totally my fault.

I'm glad they made it.

When reading your description of the fish flipping over from the bottom and going to the middle and the fish at the top also coming down to the middle, I can't help but think of that Simpson's episode where Homer gets Pinchy the lobster.

When he first gets home, he sticks Pinchy in the tank with the goldfish. Pinchy immediately goes belly-up at the top. Homer adds salt, pinchy goes to the bottom, rightside-up) and the goldfish flips. Adds water and the reverse happens. He keeps going back and forth until both are sort of in limbo, sort of half alive at in the middle. lol.

Anyway, I ramble... good save.

 

[ingg]

It isn't the CO2 affecting KH..... how to say...

KH is not affected by CO2. CO2 is not a strong enough acid to break down KH readings.

Something else is going on in that tank.

Something sucked up the KH, which in turn eliminated the buffer for the CO2. PH suddenly then plummets without the buffer.

ppm of CO2 is ppm of CO2, period. It is toxic beyond a certain ppm.



Odd thing to try and explain, as yes a CO2 dump can kill via the acidity of the CO2 itself burning lungs - but something else is going on in addition to any CO2 woes.

 

[Andrewtfw]

It was not co2 dump. The the tank was refilled three weeks earlier and is still registering nearly full. After this incident, I played with the regulator and found that I could not increase the amount of bubbles in the counter regardless of which of the two valves I adjusted.

Ingg- As for co2 not impacting Kh, perhaps the Kh level was very low prior to the release of co2. Would co2 then be able to crash the Kh? In pushing the Ph down, is Kh impacted? I am out of my element here. I appreciate your insight and knowledge.

I do not work on that tank frequently enough to monitor change in Ph/Kh over time.

Regardless of the cause, I am happy that all fish are doing well.

 

[ingg]

CO2 can't crash KH, only PH.

Well, technically, yes, it is theoretically possible. Put it this way - even at 500ppm of CO2, you still cannot affect KH by a single degree of your readings (I think it is roughly 1000 ppm to affect it if I remember it right). The amount needed is ludicrous in other words, we couldn't do it it an aquarium.

In low KH, CO2 levels will indeed crash PH.

Essentially, KH acts as a buffer for CO2's ability to lower PH.

The higher the KH, the less CO2 addition lowers PH. This is why you use PH meters or drop checkers - use a controlled KH solution to accurately count CO2 levels. It becomes very important in harder waters, as PH drops become minimal in highly buffered water.

(Please note - this is a "false" PH drop in terms of what fish want. Fish care about TDS, not actual PH. Hard water is still hard water, even if laden with CO2! Fish also do not care about the PH swings cause by CO2 going on and off in daily cycles - because again, they care about TDS of the water, which remains the same. Fish only care that you do not burn their lungs with CO2, hence the typical ~40ppm limit we have for aquariums - after that, the acid inhibits ability to absorb oxygen.)





To the tank in question...


Something is probably wrong with the regulator. Two knobs - high side and low side, like a Milwaukee?

Then there should be a third knob, the needle valve?

Else, it has one pressure side controlled, and you have one big knob and a little knob on the needle valve...

Either way, if you open up the needle valve, you should be able to make that thing look like it has a huge airpump on the back of it....

I would start to suspect something stuck in the regulator, stuck in the needle valve, or a blown regulator, which could indeed be doing bursts of pressure. Take it off, open it all the way up on all knobs - can you blow through it?

Look for particles or moisture. Moisture in a regulator body is BAD.

Look for plumber's tape being used on joints. Again, BAD.

 

[Andrewtfw]

You are correct in that it is a milwaukee regulator. When the needle valve is open, I get the same amount of co2 in the counter as when it is nearly closed. I have a milwaukee and a blueline of my own and know that this is not how it should be working. My neighbor has already ordered a new milwaukee regulator to be installed this weekend.

Thanks for the clarification and education regarding co2, ph and kh. I am always pleased to be learning something new.
-Andrew

 

[Tony]

Here, check out this chart, Andrew. I use it to dial in my kH and CO2 levels in my planted tank using a pH controller and an electric solenoid on my tank.

http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html
I keep my kH around 6 and set my pH controller to kick on whenever pH goes over 7.0. This way, I don't have to worry about pH shifts from too much CO2 (or suffocating fish) or wasting CO2 when the water reaches saturation. Since it's also really tough to test for CO2 levels directly (or accruately for that matter), this is the easiest way to figure them out.

I have this controller (http://www.aquaticeco.com/subcategories/564/pH-CO2-Controller-Smart-Controller). I got it about 6-7 years back and don't remember them being that expensive then, but even at $118, I'd rather go with it than the possibility of nuking my fish. It will also pay for itself by not wasting CO2 and night or past the water's saturation/equilibrium point.

controller + kH = good

 

[ingg]

The chart is also a faulty method overall, as PH is affected by ANY acid, and not just CO2. This means tannic acid leeching from wood, anything, it alters readings. It is an okay baseline, but if you want to be dead on accurate... drop checker. I'm not a fan of probes because of the cost/value comparison (drop checkers are simple to use, only cost a few bucks, and don't have probes that can go faulty), but they are a more hands off automated approach, indeed!



Tony - you really don't have to worry about PH shifts from CO2. I know probe/PH meter controls, but if you wanted to turn it all off at night, it doesn't hurt anything. I turn off CO2 in all my tanks at night, as do most I know.



We are used to having fish described as living in a certain PH. This is a wrong way to see it/describe it.

What fish care about is TDS in the water - they actually adjust their blood chemistry for it. Low TDS to high TDS is an easier blood chemistry adjustment than high to low, neat tidbit.

High TDS just about always means high PH. Casual fishkeepers don't test for, or understand, TDS - so LFS and most others use PH instead, as it is a simpler test and one more people can relate to.... but it isn't what we are really after.


PH swings in nature are natural and everpresent, especially in the planted tank biotope worlds. TDS, though, remains stable.

 

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