Day 2 Of Hagen CO2 Kit, But I think my water stats are wrong?

[Mantis_22]

Hello, two days ago I setup the Hagen Nutrafin CO2 kit. Before I added it to the tank the water stats were a PH of 7.4 and KH of 2 Degrees. Today I checked my water stats and the PH is around 6.8 but the KH has went up to 5 KH degrees. I thought when PH goes down KH does too? I havent added any buffers today but im going to go to the LFS to pick up some crushed coral in case someone on here says to add it. Can someone help me out?

[anonapersona]

That happened to me, turns out the gravel had some shell or coral or somehing that dissolved when the pH dropped. Could also be a rock or some decoration in the tank.

Now, with the initial Kh of 2, now 5, you might be fine if you just leave it alone. Keep monitoring the KH, and calc the CO2 levels from a chart.

Aquabotanic CO2 Chart (http://www.aquabotanic.com/charts.htm)

It might stabilize, or get worse, I don't know. It is not as easy to control the gravel as it is to control coral in the filter.

[djlen]

CO2 will not make the kH go down. The carbonic acid in the CO2 will affect the pH downward. Test your kH again tomorrow. I don't know of any way that the addition of CO2 will increase or decrease kH.
Len

[anonapersona]

Originally posted by djlen
CO2 will not make the kH go down. The carbonic acid in the CO2 will affect the pH downward. Test your kH again tomorrow. I don't know of any way that the addition of CO2 will increase or decrease kH.
Len

Len, I think you missread the post. The question was why has the KH gone *up*. As the pH goes down any coral or shell in gravel can dissolve, raising the KH.

Same as adding coral to the filter to raise the KH.


Not all aquarium store gravels will tell you if they are reactive.

My experience with this was when I added brown pebbles, regular colored fish store stuff to my flourite gravel in a CO2 supplimented tank. My KH went from 8 to 13.

So, I bought another type of gravel, this time epoxy coated, and in the process of washing it found that it was about 5% shell and the epoxy coating was spotty. I gave up and pulled the pebbles out (by hand, where they were mixed with flourite) and covered it all with 100% Flourite. I later tested the pebbles with vinegar, they didn't visibly foam, but you could hear a small sizzle from them.

[Sumpin'fishy]

I, too, have a raise in my KH. My KH used to drop when I was adding CO2. Over the time of about one month, it went from a solid 5.4 KH to below 3 KH. I decided to add a small bit of Crushed Coral to the filter. It ended up raising my KH to just over 6.0. I decided to discontinue the use of the coral. I have been going about 2 months now with no coral or any type of other buffer added. Guess what my KH is now?........7.0+ !!!!! (it's been at least 7.4 at some times)

How in the world does that happen? It is now higher than ever! I have 50/50 Silica sand/ Flourite Red. This aren't supposed to buffer the water at all, as far as I've ever heard or read. Why is it higher now than when I had the Crushed Coral in the filter? I don't even use the same filter now! Does EHFIsubstrate Pro buffer the water? I really would like it to get below 6.0 KH, if possible, but I'm not going to worry about it unless it continues to rise (it has slowly gotten higher). My pH is currently between 6.8 to 6.9 depending on time of day, due to CO2 concentrations. My tap still comes out at a steady 5.4 KH. Even my cichlid tanks with tons of limestone in them only have a 5.4 KH!

........hhmmmmm? Anyone have any ideas why this happens?

[Mantis_22]

ill do tests tomorrow.

[anonapersona]

Do you use the Hagen mix? It does have baking soda in it, if youve ever gotten any up the line and into the tank, that might be part of it...although this is quite a stretch, not really likely.

[Mantis_22]

i use the official hagen tablets (activator/stabalizer). not DIY recipe. As for it leaking into the tank.. impossible, i have a check valve and the hose is looped.

[Sumpin'fishy]

I used the Hagen mix packets at first until they were used up, but now I use my own brew.....much better results too. I don't ever see any kind of water or anything going into the tank in mine either.

[Mantis_22]

Todays water results

pH - 6.8
kH - 6 degrees

[djlen]

Mantis - try this if you're not already doing it. When you test your kH rather than using 5 mls put 10 mls in the vial. Then use the formula: 2 drops= 1 point. ie. 12 drops = 6dH......11 drops = 5.5dH. It'll give you a more accurate reading than using 5 mls.
Your kH and pH should both level off in a day or two. Your pH will start to rise when the mixture is due to be changed. If your kH continues to rise you have to find the cause of that.
What size tank are we talking about? According to your numbers you are pushing 28.5ppm CO2.
Len

[Mantis_22]

10 gallon...

What could cause low PH and high KH?

[djlen]

Baking soda or crushed coral will cause kH to rise. Do you have or have you added any wood to the tank recently? I use African Root in all my tanks and it throws my readings way off. If anything wood will usually soften the water, not harden it though.
You haven't added any sea shells or ornaments to the tank have you?
If none of the above, I would think the kH will stabilize soon.
BTW, it's not that unusual to have a kH of 5dH or so and the addition of CO2 can make the pH come down without lowering the kH. kH is your water's buffering ability. That doesn't necessarily change with the addition of CO2.
If I missed it, what kind of substrate are you using?
Just for kicks, why don't you take a sample of your tap water and let it sit out overnight. Let it gas off anything that's in it and then check the kH against the kH immediately out of the tap.
Len

[Mantis_22]

no wood in the tank, just a few pieces of clay pots for ornaments. Also including the real plants. I guess like you said the KH wil stbalize in a few days. The substrate is nothing special, just wal-mart gravel :)