Comment by Steve Heitman on November 13, 2012 at 8:06pm

Interesting. Makes sense, but a question. So, I have hard well water as a supply. Naturally Ph will be high due to the mineral content.
So, why does Ph fluctuate from the 8.4 source down to 7.4 out of the tap, and then buffer back to 8.4?
Filtration?

Interesting about the RO water. I'm going to give that experiment a try tonight

Comment by ŦůRbö ۰ Ҏяѻ ۰ on November 13, 2012 at 8:57pm

I have well water as well. Yes, the filter. An RO filter fliters out the buffers, hence the RO cant hold a pH. An open container of RO water driven from the country to a big city will change pH along the way, get a higher pH in the city, and then the pH will lower when it gets to cleaner air. I have tested this. RO has no buffers, Water that has buffers will "remember" its original pH.  The pH can and will change depending on things; like co2, rocks, filters, substrate, air quality,... but remove those factors and the water will return to the pH it first "remembered." This is why I say to just work with what you got. My well water is around 7.8 from the tap. In my tank with co2 it is 5.8, but since co2 leaves water instanly and the pH will bounce back to the normal ( in the tank this takes time, the time is depentant on the gallons, and th ewater movment, still water takes longer while movin water makes the co2 leave faster (like shaking a soda, it'll lose co2 faster if you shake it.) My 36 gallon will take an hour to get back to normal so no harm to the fish ) But if one uses the bucket and add tank water method of acculimating fish the pH will change the second the water leaves the tank. So if you are not aware of this you'll acclimate your fish to the normal pH instead of the lower tank pH. You have to turn the co2 off and let tank staibilize pH, acclimate the fish(es), add them, and then turn the co2 back on and the pH will slowly lower without harm to the fish.

Comment by D r R on November 14, 2012 at 12:22am

The reason your tap water is 7.4 is from co2 saturation. It stays at 8.4 in the tank because it has gassed off most of the co2. If you're not adding co2 then the tank is only getting so much co2 from surface agitation.

You can also see a change in ph if you test during the photoperiod (middle to end should have the highest ph) and test again when the lights have been out for a period of time (right before the lights come on should test the lowest ph). (Assuming you have a decent amount of plants in the tank.)

Comment by Steve Heitman on November 14, 2012 at 3:14am

Thanks D r R!

I am in full agreement, and expressed this same answer to th OP's question earlier in the thread.

 

However, Turbo dismissed that answer with a statement that "flowing water gasses off CO2 immediately...if it even ever contained it", and then went into a lengthy explaination as to atmosphere, polution, and local is the reason the OP's pH differed out of the tap from what he was reading in his tank.

I'm always up for a good scientific discussion, and before I called B.S. on the atmosphere theory in this particular case, I directed that question to Turbo. I even gave him an out....Filtration?

To which he used, but in regards to RO water. And thus, never really answered my question. Actually left me with more questions about his theory.

 

Now, Turbo, don't get me wrong. I'm not trying to flame, or start an argument here. In fact I pretty much agree that RO water probably does change pH from place to place due to air quality, gravel, ect. However, I disagree as to the speed of the change that you allude to. I believe it's going to take some time...some gas transfer...agitation of the water. Hence, I'm going to run that experiment you proposed earlier. Besides that why would someone waste $200 on an RO filter if pH isn't going to maintained for a length of time? Other than removing pollutants, solids, nitrates, ect.

CO2 is heavier than O2, right?

 

Pat, sorry for highjacking. Don't bother messing with your pH. Chances are good that your Rams were captive bred which makes them more tolerant to a higher pH. Also, if the lfs is close to you they are probably using the same water source.

 

Now...don't go trying to put some wild Discus in that water

 

Comment by ŦůRbö ۰ Ҏяѻ ۰ on November 16, 2012 at 2:00am

Test it. I spent the 300 bucks for an RO system. (twice, at both my houses) I can fill a bucket with 1 gallon of RO water, test it right then, or test it out of the faucet, test the gallon of water an hour later and it will have gone up at least 2.0 to 2.5 pH. Now that's just a gallon. The time will differ depending on the amount of water. My ten gallon neon breeding tank filled with RO water, went form 5.8 to 7.4 in 6 or so hours.(No fish, no substrate, just a platic plant and a piece of driftwood & sponge filter) Test the gallon every hour and you'll see. I'll even make a video on this. I'll even do it in the lab at school so you know its real. I even tested this with a towel over the bucket, so that lowered the amount of air that was in contact with the surface. Still went up. Let me know when you test it.

I was referring to well water. Well water will leave the well at lets say 8.0 Potential Hydrogen go into the holding/pressurizing tank(at least my does) then through a filter system before entering the house, it'll come out of the tap at a lower pH; due to the filtering, and then bounce back to its original pH.

I cannot answer your question on why someone would buy an RO system.

Besides, how many poeple know that RO doesnt hold pH? You didnt.

I bought mine for lower Gh (not pH), lower metal counts, and saves me from having to buy a ton of water conditioner.

Co2 is heavier o2, yes, very good. But seeing that water is heavier than Co2...

A 2 liter of soda, once opened, and resealed will lose Co2 in 2 to 3 days. Thats in a sealed container. Explain that? The Co2 is still in the bottle but not being absorbed by the soda?

fast flowing water doesnt loose Co2?

Not here to argue, or prove I know what I'm talking about. I run my tanks the way I run my tanks, and I havent failed a bio class. So yeah. Oh and time will very on air quality; but at least 12 hours and the RO will bounce its original pH (normally the pH of the tap water).

 

Comment by Steve Heitman on November 17, 2012 at 9:32am

32 hours with little change.
RO out of the tap 6.8.
3 - 1gallon samples now read 7.0
Samples placed: outside, kitchen, and garage.

Tap water 7.4 out of the tap
8.0 after 12 hours
8.4 after 24 hours
8.4 after 32 hours
(Guessing that this might explain why when you release the pressure on a coca cola bottle and it still goes flat even after you put the cap back on. Because you released the pressure the liquid was under)

Comment by Steve Heitman on November 17, 2012 at 9:46am

Starting a new test today with my tap water.
Filling a 1 gallon container with tap water. To which I will add a drop checker with 4dKh solution and bromothymol blue.
Problem is that these results are not instant, but 12 hours should be enough to detect if there is any CO2 present in tap water.

Comment by Steve Heitman on November 17, 2012 at 9:55am

Due to the 1 point swing in the pH of my tap water(7.4 to 8.4) in 24 hours I can expect co2 to be roughly 20-30ppm straight out of the tap...which will be detected if the solution shifts towards green.

Comment by Steve Heitman on November 19, 2012 at 11:45am

All samples still read 7.0 after more than 72 hours.
My drop checker test was inconclusive. Color of the solution did shift, however it did not go green enough for me to say there is x concentration dissolved co2 in tap water.

Comment by Steve Heitman on November 21, 2012 at 11:19am

Finally reached 7.2.
Ending my experiment because I got my answer.
Untrue??? No, because the science is there. I believe if I wait long enough it will eventually get back to 8.4...maybe.

Scientific theory that was over-simplified for the sake of argument??
Absolutely.

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