OH NO, NO!!?!...KH rising w/ new co2, tell me its not so... - The Planted Tank Forum
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post #1 of 9 (permalink) Old 03-29-2006, 01:36 PM Thread Starter
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OH NO, NO!!?!...KH rising w/ new co2, tell me its not so...

I don't know if this is a substrate issue, water parameter issue or something else.

Well, where to start, I thought I was doing such a wonderful thing upgrading my tank and introducing pressurized CO2....BUT now my Kh has gone up 3 full degrees just two weeks.

So, I'm wondering, and worrying and reading, and searching and reading. NOW i've got a very sick feeling in the pit of my stomach!
Please tell me its not so...

I've read that the carbonic acid from the CO2 can react to disolve something causing the Kh to start rising. So testing should begin to locate the problem. I also read to try testing substate by putting it in vinegar.

OH NO, my pea gravel in white vinegar looks like champagne!!!! I tried some of the Mexican terra-cotta chunks I've got in there too (from beautiful, old broken pottery). No reaction with the vinegar and terra-cotta. But the pea-gravel is FIZZING AWAY!!! FIZZ, fizz, fizz.

It would be oh so nice if I could hear that I don't have to rip down the tank and change out my substrate. I don't want to go thru the expense, the heart-ache, the back-breaking hard work etc, etc if it's something else? How accurate is that vinegar testing? Could it be something else?

I did not seem to have any problem with the KH and gravel up to this point.
Should I shut down the CO2 for now?

OH PLEASE, oh, please, oh please?????

OH, yeah....its a 75 gallon monster. Why didn't I start small???

The tank has been up since first of Nov, 2005. Lots of plants.
bottom 2"-Flourite & Shultz Aquatic soil 50-50 blend
top 1" - generic pea gravel from hardware store

Tap Kh- 5.5
Tank Kh - 8.5
Tap Ph- 7.6
Tank Ph-6.8

All advise is most gratefully appreciated.
Please let me know if any other tank details will be helpful.
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post #2 of 9 (permalink) Old 03-29-2006, 02:53 PM
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If it fizzes in vinegar i think you have a winner.
Do you have an AP Nitrate test kit ? Bittle #1 contains 41% hydrochloric acid - which is very good for testing rocks.
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post #3 of 9 (permalink) Old 03-29-2006, 04:28 PM
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Ouch indeed!

It sure sounds like the pea gravel is the culprit. You're probably better off in the long run just biting the bullet and getting rid of the stuff if you want CO2.

It's not quite so bad, though, is it? I mean, you don't have to do a total breakdown. You can probably scoop up most/much of the gravel off the top of the fluorite with a fish net, then carefully uproot whatever plants are necessary to get at the rest. I wouldn't think leaving behind a small amount of gravel that's worked its way down into the fluorite would be a problem,as long as you keep on top of things and do necessary water changes. You might even find you like running the tank at a bit higher KH.

Overall, many of the plants will have to go through replanting and recovery of course, but hey, just keep telling yourself it's an aquascaping adventure .

Best of luck.
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post #4 of 9 (permalink) Old 03-29-2006, 04:36 PM
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The only thing you might want to do is wait a few weeks and see if it subsides much like Eco reportedly does after a few water changes. Restarts are a drag to contemplate. But once you dive in it will be over before you know it. You can move the fish to a plastic trashcan with the same water, a heater and your filter for the day. I had to restart a 90 with bad substrate. At least you have I.D. the culprit.

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post #5 of 9 (permalink) Old 03-29-2006, 06:08 PM Thread Starter
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Saga continues....

More fiddling...
I've tried testing the Kh of straight vinegar: 0! My trial solution with my Mexican pottery also tests at 0. The trail solution with the pea gravel and vinegar after 3hrs soaking tests at.....25+ degrees of KH. After 25 drops I stopped adding the test regent because I did'nt want to blow it all! After the pea gravel has sat in straight vinegar all morning I strained it out, thouroughly washed it and put in back in a vinegar soak. Still loads of Fizz, fizz, more fizz. Many tiny bubbles but also some large glop..glop, bubbles to the surface.

It definately seems this gravel is a problem. Its begining to sink in the job that's ahead of me. I've also just spent 2 hours over in the substrate forum trying to figure what to use for a replacement.

Someday maybeI'll actually get ahead of this learning curve, have my tank stable & prospering then can go back to the rest of my life.???

Green is Beautiful,
I've several different test kits, a Seachem nitrite/nitrate and Tetratest Laborett. I haven't the one you mentioned.

Much thanks for the wishing of luck! Looks like I'm going to need it.
I don't understand what would be the benefit of running the tank w/ a higher KH. I 've read that high KH may actually bother fish more that Ph fluctuations and/or GH hardness. Of course there is so much information available my head often spins! I swear if I'd known I would be learning this much chemistry I might have just gone ahead and become a doctor!

I am very glad for your idea of using a trash can. When I stated this tank I had no fish. Now, however, there are many little critters for me to really worry about. I think I am almost as intimidated by the idea of trying to net these guys out to safety as I am with tearing up all the plants and hauling out 50# of gravel.

Thanks Again!
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post #6 of 9 (permalink) Old 03-30-2006, 07:41 PM
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Originally Posted by Rod Hay
More fiddling...
Much thanks for the wishing of luck! Looks like I'm going to need it.
I don't understand what would be the benefit of running the tank w/ a higher KH. I 've read that high KH may actually bother fish more that Ph fluctuations and/or GH hardness.
Hey, like Betowess said, once you jump in there, it'll be over before you know it. Plus look at all you're learning about substrates .

Regarding the KH remark, I didn't mean a really high KH, just more than your normal KH of 5.5. Mine runs around 7-8, for example (hard water). I wasn't aware of the fish angle about higher KH though. I'll have to look into that. I was thinking more just about managing CO2. With higher KH, you can put more CO2 into the tank at a lower pH (see pH/KH/CO2 chart), and CO2 losses, say from an airstone or from turning CO2 off at night with a solenoid, result in smaller pH swings. It's always a tradeoff though. Softer water is generally better for a greater variety of plants, or at least that's my impression from reading. I've still got a few hundred varieties/species to try growing before I'll know for sure .
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post #7 of 9 (permalink) Old 03-30-2006, 07:47 PM
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A lesson learned. Test the gravel BEFORE you put it in the tank.
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post #8 of 9 (permalink) Old 03-30-2006, 09:35 PM
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Is your water fairly hard and alkaline to start with? Vinegar is actually a pretty weak acid. Many times, lime containing rocks or gravel won't fizz with vinegar, but will with stronger acids.

I'm a bit surprised you weren't having problems already with rising pH and GH.

Very likely, removing the gravel will head off problems you might have had later, even if you hadn't added the CO2 unit. Think of it that way. At least now you know something bad might have happened in the future, and you're heading it off.

The pea gravel would be great for African Cichlids, though!
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post #9 of 9 (permalink) Old 03-31-2006, 01:29 PM Thread Starter
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Update-the Good news & BAD news!

Although I did not test the gravel, I used it on the recommendation of a co-worker who has run freshwater and saltwater tanks. She told me she purchased this and used it without problems. Oh, well, yes a tough and expensive lessoned learned! And to boot I can't really ream-out that co-worker too much because its my Boss!

The good news:
As I needed to purchase more aquarium safe, plant-friendly gravel I went to my favorite LFS: All Oddball Aquatics in Pittsburgh. Along with my bags of Flourite I scored some narrow-leaf Java Fern, Blyxa japonica and some Marsilea quadrifolia to add a little fun to this tank re-do.

The BAD news:

I was thinking/ hoping I could just skim off the 1- 1 1/2" of the pea-gravel top layer and then be back in buisness. NO SUCH LUCK! With the minimal re-landscaping I've done, and re-planting of stems, along with now up-rooting some 40 or 50 plants the bottom half of my substrate that was Flourite & Shultz is now pretty well a complete blend: Flourite/Shultz and all the small grains of that pea-gravel. Its now ALL coming out and I'm on my way across town to a local Lesco dealer for 50# of Soilmaster Select.

My back already aches/
the new mulch around the bird bath looks pretty!
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