# [Wet Thumb Forum]-PH Crashing, and I don't know why.



## TheDude (Feb 17, 2003)

I made a post about 2 months ago about DIY CO2 through a 5 gallon carboy. Well, yes, it was overkill. I've since switched over to 2 2-litre bottles and my PH has crashed. I use a powerhead and gravel vac for diffusion, which works well. I've had the same problem with 1 2 litre bottle on the same tank. I added the second bottle because I wanted to stagger them, so as not to disrupt the PH more than I needed to. The tank is 37 gallons. 

No inhabitants...I removed them

I am using Aquarium Pharm's test kits for both PH and KH - 

Tap PH: 7.7 - 7.8 (verified with water supplier as well)
KH: 6

Tank PH: 6 - the lowest reading of the kit, bright yellow. This is constant througout the day. I've tested at lights on, and lights off.
KH: 6

I'm new to this. Could I simply be injecting too much? If my landlords use a water softener (which I don't know) could the test results be incorrect as a result? My plants only pearl before I go to bed, or 1 hour before lights out. With the carboy it was constant. I expected a crash with the carboy, not with the smaller set-up. What gives?

Thanks all


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## TheDude (Feb 17, 2003)

I made a post about 2 months ago about DIY CO2 through a 5 gallon carboy. Well, yes, it was overkill. I've since switched over to 2 2-litre bottles and my PH has crashed. I use a powerhead and gravel vac for diffusion, which works well. I've had the same problem with 1 2 litre bottle on the same tank. I added the second bottle because I wanted to stagger them, so as not to disrupt the PH more than I needed to. The tank is 37 gallons. 

No inhabitants...I removed them

I am using Aquarium Pharm's test kits for both PH and KH - 

Tap PH: 7.7 - 7.8 (verified with water supplier as well)
KH: 6

Tank PH: 6 - the lowest reading of the kit, bright yellow. This is constant througout the day. I've tested at lights on, and lights off.
KH: 6

I'm new to this. Could I simply be injecting too much? If my landlords use a water softener (which I don't know) could the test results be incorrect as a result? My plants only pearl before I go to bed, or 1 hour before lights out. With the carboy it was constant. I expected a crash with the carboy, not with the smaller set-up. What gives?

Thanks all


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## imported_Mark (Mar 4, 2003)

On a 37 gallon tank? Shouldn't be too much. I was running a similar setup on my 45 and never had my pH dip below 7. What's your GH level? If there is no or low GH, your water won't have any buffering capacity. KH 6 is fine, but need to know other parameters. What kind of substrate do you have? You might want to look into adding some dolomite to stabilize your tank if it turns out the GH is low. I had a similar problem in a 29 gallon. Stuck some dolomite gradually and eventually the PH topped out at 7.


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## TheDude (Feb 17, 2003)

Tap GH: 6
Tank GH 10
Substrate is 2 inches of gravel with Flourish tabs.

110 watts PC - 2.9 wpg

I'm confused. I thought KH dictated buffering capacity, not GH. Ahhh well. This leaves me wondering if the kits are bunk. If I go with what the kits *ARE* telling me, where should I go from here?

Thanks


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## EDGE (Feb 28, 2004)

how old are your test kits? they could cause a problem if they are too old.

water softener will make the result incorrect as well.

what is the plant load like in the tank?

I have never did find out if lack of nutrient will slow down the useage of co2 in return cause a huge build up of co2 in the water. Can anyone answer that question?

75 Gal, 4.6 WPG MH 10 hour, pressurize co2 /w controller, Fluval 404, ph 6.8
Mike's Canadian Aquatic Plant Page
A Canadian's Plant Traders website


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## Rex Grigg (Jan 22, 2004)

kH is the buffering ability of the water.

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## imported_Mark (Mar 4, 2003)

Well my bad, I was under the impression they went hand-in-hand. Anywho, I would agree with EDGE about the age of the test kits. Might want to swing by your favorite LFS to get a second opinion on readings.


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## TheDude (Feb 17, 2003)

The kits are only about 3 months old. Who knows how long they were sitting on the shelf. The only plants I have are Sunset Hygro, Hygro Difformis, and Lilaeopsis Bras. The tank is too new, and I keep messing with things to try and keep any other plant at this point. They are however, very happy plants. How many times has this been asked...what test kits are good for KH, GH, and PH? I thought these were the easiest to test for.

Thanks all


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## anonapersona (Mar 11, 2004)

First, if the KH of 6 is correct, with the pH at 6 you have 180 ppm CO2 in the water, which is almost off the edge of the charts, a massive overdose and it's good there are no fish in the tank. 
You say your plants only pearl very late in the day, this would seem to support a theory that the CO2 is building up unused though I've never seen such a theory proposed. Hard to imagine at the indicated CO2 levels. This makes me wonder about nutrients, both macro and trace and those unknown elements that we supply through water changes and fish. What do you add to the tank for plant nutrition?

Wild guess, without fish, you have eliminated water changes. If so, then even if you were adding most of the needed stuff, the missing elements might be from water changes. 

Second guess, you top off the tank with tap water to replace evaporation. And you do this rather frequently. The tank GH is higher than the tap GH. This suggests that while elements are being added, none are being subtracted by water changes. Along with the concentration of the tank water, plant released chemicals might be building up, slowing the plants.

Third guess, you have used pH regulating chemicals in this tank and they are still in the tank. I have been told that other things can be read as KH that are not actual buffers, though this has been laughed off when I've repeated it. If some large portion of your KH reading was not a carbonate buffer, like phosphates from some pH controlling chemicals, and your true KH was lower then the whole thing makes much more sense. I've recently read that some bottled waters can be high in phosphates.

Experiment: Take some tank water and let it sit overnight, aerated if possible or maybe a power head to mix it well. Measure the pH and KH, on the charts in the Library here determine what the CO2 content is. It should be at ambient CO2 levels, like 1.5 to 3 ppm. If it is any higher, then part of your KH is a false reading. Determine what that false portion is by what the KH would have to be at CO2 of ~2 ppm and the pH you measured. If you real KH is like 2 or very low, then you need to raise it to a true KH of around 5 or so to stabelize the tank. It is possible that you have burned up all the true KH in the tank with the high CO2 doses you started with.

anona, playing detective


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## TheDude (Feb 17, 2003)

Anonapersona - I dose Yamato Green and K at water changes, which are 25% weekly. I've got a healthy batch of copepods and amphipods, not that it matters, but they are interesting little critters. The tank is covered, so evaporation is not a factor. No PH regulating chemicals are used. I'm eager to try your experiment and will do so tonight. I'm hoping that this is the case, thanks for the help. I'll get numbers up here in the morning. 

Happy Friday


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## anonapersona (Mar 11, 2004)

Well, I was guessing! 

anona, still learning


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## Vicki (Jan 31, 2003)

Take a cup or two of tap water and add 1/2 a tsp. of baking soda to it, mix well, and then test the ph. If it still reads 6.0, throw out your ph kit and get a new one. If it reads 8.2 (or rather, 7.4, which is probably the upper range of your kit), I'd proceed with the KH experiment and see what happens.

http://www.wheelpost.com


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## TheDude (Feb 17, 2003)

Sorry for the dely in response, ISP problems. My PH test kit is fine. My KH test kit on the other hand, always reads 6dkh. From the tap water, from the tank water, and from the experiement water. So, I guess the kit is bad, damn!

thanks


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## EDGE (Feb 28, 2004)

Some of the LFS will gladly test your water. bring a sample in for them to test and see if there is a different between your kit and theirs.

75 Gal, 4.6 WPG MH 10 hour, pressurize co2 /w controller, Fluval 404, ph 6.8
Mike's Canadian Aquatic Plant Page
A Canadian's Plant Traders website


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## TheDude (Feb 17, 2003)

Neither of the local lfs had KH test kits, and neither could test it for me. So after an hours drive north, where I originally bought the kit, I am told that nothing is wrong with it. I kept telling them that it's been reading steady at 6dkh, on anything I test. At any rate, it was very dis-heartening for me, I just don't believe this damn thing! My PH is unreadable below 6, still, after 2 water changes in one week. So I bought a different kit, the Tetra kit, which seems to hail as king supreme in the el cheapo category. Here are the numbers at 9:00pm:

Tap KH: 4
Tap PH: Unreadable or darkish blue, but water source says 7.8 - 7.9

Tank KH: 4-5
Tank PH: Unreadable below 6.0

This means that I have 120 - 150 ppm of CO2 I'm getting discouraged...


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## Rex Grigg (Jan 22, 2004)

Let the tap water sit overnight and then test it.

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## Kathy (Feb 2, 2003)

I see YOU aren't adding phosphate to the water, what about the water company????? High phosphate can affect the KH test. Don't know how high it would have to be though.

I am still not convinced there is KH in your water. What happens if you test distilled water? Have you contacted your water company for a water report? I don't seem to have the link bookmarked for water company water quality reports unfortunately. Have you repeated the adding baking soda to your tap water test to check for a change in KH?

Only thing I have read about water softening is they are mostly set up using sodium to exchange for calcium. I have no idea if softened water has a different pH than unsoftened water from the same source. I did test Brita softened water at a very low pH a couple years ago though. That's a carbon filter, I think.

I have no clue why the pH test is acting so strange. My AP test is so easy to read, blue to yellow, never had any purple color using the low range test. If test is blue I use the high range test which goes from orange to purple, get the pH fine. If you mix half tank and half tap the pH ought to be somewhere between too low and too high, right? Try that. 

Do a pH test of tank water and shake that test to see if the color changes, mine goes from bluishgreen to straight blue indicating pH of 6.8 then 7.4, the change is the CO2 that has been driven off. Test the tank right after a water change, should be more than 6, less than 7.8, right? Compare that test to the one mixing half tap and half tank. Test every hour for a while. This is a junior high school science experiment going here!

I had a question about some test kits I bought. An email got me a quick response. Bet you can find out how old your tests are from the company too.

If your inverts are okay that is a good sign anyway. Your plants are fine also, that's great. Low pH or weird water isn't good for them either. This may all be a water testing problem.

What happens if you stop the CO2 going into the tank? Do you have any interesting algae problems in the tank? What is in the tank? Wood, plants, rocks, type of gravel? 

Summary, get water quality report from the water company, public property- your right to know, they have to give it to you. Looking at phosphate, calcium, carbonate, magnesium, nitrate and organic acids. Anything interesting in there hope somebody who knows something about chemistry chimes in!
Test tank water before water change.
Test tank water after water change.
Test tank water and then shake it to see if the pH changes. 
Repeat the water + baking soda test on tap and tank water to check KH test.
Take CO2 off tank to see if pH goes up over period of 24 hours.
Contact water test manufacturers for expiration date and any other information they might have.


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## TheDude (Feb 17, 2003)

Ok these are concrete numbers now. I am certain. I just tested PH at my girfriends lab.

Tap: 7.75
Tank: 6.48

Tap KH: 6
Tank KH: 5-6 

I know this little deviation in tank KH is significant. In Chuck's calculator it's the difference between 49.67 and 59.67 ppm CO2. But it's still too high. What are my options?

I am cetain that the KH reading is correct, I have used 3 different kits in the past week, all with the same readings. 

Thanks


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## EDGE (Feb 28, 2004)

The most effective method is to lower the output of co2.

I wouldn't go and reduce the output with some sort of valve. DIY pop bottle aren't design to take pressure build up.

75 Gal, 4.6 WPG MH 10 hour, pressurize co2 /w controller, Fluval 404, ph 6.8
Mike's Canadian Aquatic Plant Page
A Canadian's Plant Traders website


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## TheDude (Feb 17, 2003)

Ok, so I am perplexed beyond belief that my DIY rig is overdosing the tank. But it must be. I have 2 bottles on it right now, I'll take one off. In the meantime, I ordered a regulator and it should be here this week sometime. It's going on my 45 gallon tank. I'm feeling ignorant, I have this picture in my head that you need a certain amount of CO2 going in to benefit the plants. But if I need to down the amount being injected, which it's obvious that I do, won't this end up being useless for the plants? If just lowereing the amount being injected is all I need to do, while at the same time still giving my plants the needed amount of CO2, then I will do exactly that. I think my view of this is skewed.


Thanks


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## Vicki (Jan 31, 2003)

Just relax and accept the numbers, Dude. One 2-liter bottle should be enough to supply ample CO2 to a 37 gallon tank, and your numbers confirm that; you have about twice as much CO2 as you really need. Solution: remove one bottle. End of problem.

http://www.wheelpost.com


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## TheDude (Feb 17, 2003)

The Dude abides. Guess I'm reading too much into it.


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## imported_Sicklid (Feb 27, 2003)

Just out of curiosity, what recipe of yeast/water/sugar are you using? Also, I'd recommend reducing the amount of yeast (assuming its too high) in each bottle instead of just eliminating one of them.

_*BlackMesaDesigns*_


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## TheDude (Feb 17, 2003)

I'm using the recipe from the krib. 3/4 cup sugar, 1 Tsp. Yeast, 6 cups of water. I'm using Montrachet Champagne yeast and a Tsp of FERMAX, which is nutrient a supplement for the yeast.

Just so you know, I mixed up another 2 liter last night and hooked it up to my 45 gallon tank. The PH dove again and the fish are a little stressed, not too bad, but still to the point that I disconnected the CO2 and threw an airstone in.


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## imported_Sicklid (Feb 27, 2003)

I have two alternating bottles on my 55 that give me co2 rates of 23 mg/l. My recipe is 6 cups water, 2 cups sugar, between 1/3 and 1/2 tsp. yeast, and 1/4 tsp baking soda. By using less yeast and more sugar my bottles put out a steady amount of co2 for a lot longer (up to three weeks before they start to decline). 
I also use two bottles with 1/4 tsp yeast for my 29H, and I get the same levels for the same amount of time. Though I change bottles for both tanks every 7 to 10 days. It sounds like you are using double to three times as much yeast as you need for your 37 gal.

Plus, I've never used champagne yeast, and I don't know anything about Fermax, but all my regular baking yeast needs for plenty of co2 production is the sugar. Your yeast is having an all-it-can eat smorgasbord, no wonder your co2 is so high.

There are lots of recipes all over the web for DIY co2, you have to find a starting point and then experiment to find the one that works for your set-up. Variables include: room temperature, age/type of yeast, sugar concentration, water properties of water used for co2 mixture, and diffusion/delivery method.

_*BlackMesaDesigns*_


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## gsmollin (Feb 3, 2003)

OBTW, maybe I missed it, but what kind of lighting are you using? Plants need lots of light when they are CO2 enriched. Its strange that your plants only pearl late in the day when there's so much CO2. Maybe you need more light.


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## TheDude (Feb 17, 2003)

Sicklid - Yes, I guess that would be my next course of action. Since the 37 gallon tank is still going to be DIY, I think I'll have to tweak things. I'll try 1/2 tsp yeast, no fermax and keep everything else where it is. Maybe this will give the output some stability. A single bottle lasts me about 3 weeksbefore I get paranoid that it will stop. Then I change it out.

gsmollin - I've got 110 watts on the tank. 2.9 WPG

1 10,000k pc
1 6400k pc

11 hours a day


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