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Discussion Starter #1
First some back story..

I recently decided to check my Ph after playing around with my reactor. Anyways, I tested my Ph (in order to get gauge on the CO2) and it was way high (7.6), I figured it was something to do with the reactor, so I checked my other tank.. also 7.6.

Hmm, I thought the Ph test was faulty, I bought a new one. Tested both tanks again, 7.6 again. I wondered what the water out of my tap would test at. I tested it (with both kits).. 6.6/6.4, way down from what it used to be a couple months ago.

Now the question(s)..

I assume that my Ph tests are giving me a false positive when testing the tank water due the a lower Ph in the tank than what the test reads? Is that how the Ph test usually work? If I start at 6.6 and add CO2 it will go down, no?

If this is not the case how could I possibly be getting a higher Ph reading that what is coming out of the tap? I am adding CO2 @ 50BPM into an inline reactor, with little to no surface agitation. I have not added anything to either tank that would effect water chemistry (I have not added anything to either tank period). Kh remains at 4-5. Plants pearl in the one tank, not in the other. Growth seems normal. Fish seem happy in both tanks. I really don't get it.

Any help for my troubled mind is greatly appreciated.
 

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Vinlo said:
I have not added anything to either tank that would effect water chemistry (I have not added anything to either tank period). Kh remains at 4-5. Plants pearl in the one tank, not in the other. Growth seems normal. Fish seem happy in both tanks. I really don't get it.

Any help for my troubled mind is greatly appreciated.
1. pH test kits don't tend to go bad - the chemicals used are very stable and the solution is ethanol-based, so microorganism growth is unlikely.

2. Tap water pH readings must be taken after 24 hours - with a kH of 4-5, your pH should be >7. Let it rest, then test.

3. You are not adding anything to the tank except CO2?? That will be a problem real soon! Maybe the plants in the tank with no pearling are starved for nutrients!

4. Have you looked at a pH/kH/CO2 chart to determine what your target pH should be?

Kevin
 

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You are not adding anything to the tank except CO2?? That will be a problem real soon! Maybe the plants in the tank with no pearling are starved for nutrients!
I am pretty sure he is fertilizing. I think he means he isn't adding anything to alter the water chemistry.

Did you try taking some water to the LFS and have them test the pH? I would give that a try, in addition to letting the tap water stand a day before testing that.

Mike
 

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Discussion Starter #4
Indeed, I meant adding stones or whatever that would change the water chemistry (kh, gh, ph, etc). I do fertilize - NO3, PO4, K, etc...

I will let some tap water sit for a day or so, see what happens.

Do you guys really think my tank water could be at 7.6? It has never been that high ever. It was always around 6.6-6.8 (what the charts say it sould be).

I have not taken the water to the LFS.. yet. Don't really trust any in this area.
 

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It is only a test.

I know some folks at the LFS can be pretty incompetent, but it is only a pH test...right?

Mike
 

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Vinlo said:
Indeed, I meant adding stones or whatever that would change the water chemistry (kh, gh, ph, etc). I do fertilize - NO3, PO4, K, etc...
The pH/KH/CO2 table is assuming that you only have carbonate buffers in your system. If you are dosing phosphate you tank may by running off the phospate buffer which would result in a high pH. I have not done the math to prove this though. You can test by running CO2 into a jar of aged tap water with known KH/pH etc and seeing where the pH is at saturation.
 

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No, the phosphate levels we keep do not affect pH appreciably. You need high phosphate levels for it to start showing signs of being a buffer.

Well your kits look fine to me. The CO2 of your aged tap water is around 3-4ppm, which is right where it should be. The fact your pH kits responds to the lower pH from the tap is a good sign. And as Kevin already pointed out pH kits just don't go bad b/c they use very stable chemicals.

Seems to me something is wrong with your CO2 system or reactor. Leaks?
 

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Discussion Starter #9 (Edited)
No leaks, I am putting 50bpm into the reactors with no unddisolved co2 coming out. This is a strange one. I guess I will try an old internal reactor that I know works. If the pH drop using that.. then I know where the problem is I guess.

-edit-
Hmm.. I tested my water in my bubble counter. ph6.0. Crappy. That means something is messed up with my reactor. That's pretty crappy.

Now the thread changes. The only thing I have changed it I put in bioballs instead of plastic practice golf balls last weekend. Hmm.. maybe I put in too many? What makes no sense is that there is no undissolved CO2 coming out but there is Co2 in the reactor. Hmm.

Has anyone built an inline reactor that doesn't work? If so how did you get it work?
 
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