(KH=10+PH=6.5+CO2=5bps) = Shrimps dead??!!

[Georgeer]

Over the weekend, I changed about 1/4 of the 3ft tank and added some anti-chlorine. Then dosed some fertilizer into the tank, using some moss powder and few drops of LUSHgrow-Aqua.
The Riccia and other plants showed massive bubbling activities later and the water is very clear.
These lasted for the next 2 days.

Then this morning, I saw at least 5 dead shrimp corpse among the hairgrass. There maybe more as the usual activities under the frogbits had disappreared.

Did a water test and this is the result:

PH=6.5 (ballpark as test kit is using colour code)
KH=10 (using drop by drop test, so colour changed from blue to green then yellow at about 10 drops)
CO2=5bps (24X7)
No other test kit to perform other test.

Question to seek experts help is:
1. What constitute to the death of the shrimps??
2. Is the KH too high?
3. Is the CO2 too much?

Thanks.

[Allen_1971]

George,

I would be a bit suspicious of your CO2... theres an online calculator many of us use, and that shows that your CO2 levels are way too high. However, I would expect not just shrimp deaths at that level, but lots of fish deaths as well.

Heres a link to the calculator.

Also, is there any reason why you bubble at such a high rate? How large is your tank? What do you use to dissolve the CO2? Why did you set your KH so high...i.e. what are you planning to keep?

[CT]

I think your shrimp die because of the high concentration of CO2 in your tank.

[Georgeer]

Hi Allen,

The CO2 was 1bps in the past and the Riccia wasn't bubbling at all, so I turned up the CO2 supply and "bingo", the beautiful bubbling. Even hairgrass bubble from one of the stalk.

I suspect the fishes are doing ok because of the O2 supply from the plant in the 3ftX18inchX19inch tank.
So far, a fishhead count shows all Rummy nose, Otos and SAE are still full strength.

I have no idea why the KH is so high, I am totally clueless why the KH test kit is working this time. In the past, I added so many drop and the colour didn't change at all. This time I saw the colour changed to blue, so I follow the instruction on the box to continue adding until the solution turns from blue to green then yellow. Total 10 drops were added, so KH=10.

I did a calculation at Chuck's site and the reading shows:

pH 6.5
KH 10 degrees 179ppm
CO2 94.868ppm

Is that too high?? What are the ways to lower the KH? Adding baking soda helps?

Thanks.

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On 7/28/2003 10:32:54 AM

George,

I would be a bit suspicious of your CO2... theres an online calculator many of us use, and that shows that your CO2 levels are way too high. However, I would expect not just shrimp deaths at that level, but lots of fish deaths as well.

Heres a link to the calculator.

Also, is there any reason why you bubble at such a high rate? How large is your tank? What do you use to dissolve the CO2? Why did you set your KH so high...i.e. what are you planning to keep?
----------------

[joe]

From your pH and Kh, it seems that your CO2 is more than 100mg/l. If that is the case, the shrimps would have died within an hour or so after you pumped up your CO2. Most, if not all, of the fishes would have difficulty breathing and would all be gupling air at the water surface.

I also noticed your CO2 is on 24x7. How about the lights?

[theodore]

It's high but (I believe) people using coral chips usually have it around 8-10 dKH.

Easiest way to lower KH is to change 20-40% every 2-3 days until you get to the KH you desire to maintain.

We add baking soda to raise our KH, not lower it.

[Georgeer]

Oh my, this morning I just lowered the CO2 supply to 3bps, and think it is still too high. I hope the fishes survive till this evening when I got home.

The lights are turn on from morning 0630 ~ 0830, and 1900 ~ 0100. Using the fiesta method.

So a water change is required to lower the KH, is that the only method? Or is there anything in the market that I can use to lower the KH?

I just purchsed a Seachem PH controller last week that can help to stablize the PH around 5.8 to 6.8, and has thrown in a few teaspoon after water change.
Is that the cause of the high KH?

I guess my ignorance here is causing a lot of trouble.

[chua]

Maybe there is a problem with your KH test kit. It is because with such high ppm, your fishes and shrimps should be poisoned already. You can try with the tap water. It should be around 1.
If not, you can buy KH kit of other brands.

[Allen_1971]

George,

O2 levels and CO2 levels function quite independantly of each other. Given that all your riccia is bubbling, I would say that your water should be very richly saturated with oxygen. However the risk of CO2 toxicity still remain.

Heres a link with some good articles on it.

Having said that, I am highly suspicious of your readings. At 94ppm, most of your fishes would be dead. Since they aren't, we have to conclude that the CO2 is not at that level. Which bring us to your measurements...

If you play with the calculator I showed you earlier, you should see that a small swing in your PH can provide quite large swings in the CO2 levels... Given that most generic test kits give ph at 0.5 increments, this allows for a substantial error. Often a PH pen is prefered.

Next your KH... it could be high due to 2 reason...

1) your substrate is not lime free... i.e. you have corals, or other calcium derivatives. As your water becomes more acidic (due to dissolved CO2), it dissolves these, bringing both the KH and GH up

2) Your test kit is faulty. Do a simple test... fill a pail with water, and check the KH. then put a teaspoon sodium bicarbonate and test again... you should see an increas in KH. Also, if your tapwater shows no KH, you could take a small sample of your tank water, dilute it with tap water and check again... All this is just to verify that the test kit works, and you are doing the test correctly.

[sherchoo]

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On 7/28/2003 1:33:28 PM

I suspect the fishes are doing ok because of the O2 supply from the plant in the 3ftX18inchX19inch tank.
So far, a fishhead count shows all Rummy nose, Otos and SAE are still full strength.
----------------

With high amount of CO2 in the water, livestock in your tank would not make it even with high concentration of O2. CO2 is actually toxic in high concentration and that's why we always mention CO2 poisoning.

[Georgeer]

Thanks for the info. Need to rush home quick to test the KH again. I hope that kit is "spoilt" and is giving me the false alarm.

[theodore]

Test with tap water 1st, followed by tap water + a few drops of the Seachem buffer you mentioned. I suspect that this product is the culprit for your high KH.

[Allen_1971]

Hehehe good spot Theo... I actually thought he bought a PH Controller... but on rereading his previous post again, I realise you are right, its probably a buffer of sorts. Something which is almost certainly gonna screw up your PH/KH/CO2 relationship.

[PeterGwee]

Most likely some kind of phosphate content in it.... Not just a little but definitely alot.

[nbk3]

just to reassure the others , i have coral chips in mah tank , injection of Co2 is present and my ph is about 6.5-7 and my kh is at a healthy 10 []

[Allen_1971]

Actually if your KH is 10 and your PH is 7, then things should be fine... however as I mentioned earlier, a lower ph than 7 probably means your CO2 is starting to get dangerously high... and at 6.5, its probably deadly to all fishes. Or course this presumes the absence of things like acid/alkaline buffers which can screw this relationship up.

[naturetan]

There's another thing we need to be careful if we maintain at high KH using coral. At every water change, depending on the amount, the KH could drop drastically, stressing fishes/shrimps real hard. Tap water is 0KH.

Putting too much coral chips will also increase KH reasonably fast, making it difficult for fishes/shrimps to adjust well. The dissolve rate is good to maintain at about 1 KH/week.

[Georgeer]

Changed 1/2 tank of the water last night. Checked KH this morning at about 6dKH.

Tested with tap water and the Aqumedi KH tester shown 0 or less than 1 dKH reading, so KH tester should be functioning.

Found a few more shrimps dead among the hairgrass. Fishes are all doing ok. Hope water stablise today and the other shrimps can survive.

BTW, what is the difference between dKH and KH? The Aqumedi KH tester box put dKH and the Taiwanese book I have uses dKH as well. (pardon me for my ignorance in all these units).

[Allen_1971]

KH is an acronym for Carbonate Hardness... its "K" cuz it started in german I think

dKH is a unit of measure and is short for degrees of carbonate hardness. so when you say you have a KH of 3, you could say your tank has 3dKH. Also worth noting is that these are using german degrees.

[chua]

Just wondering,

One of my friend is also using this brand of KH testkit as well. But we test it with our tap water and it show 2. Check out that Singapore tap water has KH ranges from 50mg/l to 100mg/l. Hence, is it possible to obtain this KH reading of 2 for out tap water. We are living at the west area near the Pandan Resorvoir.

Thks