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Consistant pH of 7.5, can't raise it higher


Admonition

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So looking at that, how would I set it all up?

 

Would I run airline tubing from my Tetra Whisper pump into the BRS air filter (which I've filled with the CO2 absorbent) and then plug in airline tubing at the other end of BRS air filter, and then attach my airstone to the end of that tubing, and place that airstone into my tank? Is that what your suggesting?

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I can only assume so. You would connect the air filter to the air intake on the pump so the air the pump is pulling is being scrubbed of the co2. Google diy co2 scrubbers, you may get some ideas and how to's for set ups.

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Fishtachio: will the kalkwasser raise my pH for longer than a few hours? I dose two part and my pH rises for a few hours but then drops (of course, the point of my dosing two part wasn't for a pH bump) Also, is there a way to add kalkwasser (mixed in RODI of course) as a dose straight into the tank manually? Instead of in my ATO? And what do you mean by buffer it?

 

I spoke to BRS about their air filter and CO2 absorbent and this is what they said:

 

Your question:

How exactly would I set this up for my tank, which has low pH possibly due to a tightly sealed house (CO2 built up)? I have no reactors or skimmer. Would I run airline tubing from my Tetra Whisper pump into the BRS air filter (which I've filled with BRS CO2 absorbent) and then plug in airline tubing at the other end of BRS air filter, and then attach my airstone to the end of that tubing, and place that airstone into my tank?

 

Response:

Hi Christopher, That would be about the only way to do it with your setup. That said though, I don't think it would be very effective as you wouldn't have anywhere near the gas exchange a skimmer does. Most of the air exchange that happens with an air-stone is actually from the surface agitation it causes, because the surface is exposed to your normal high co2 air, it would likely mitigate the effect of the reactor. Without the skimmer I don't think you would get much out of your investment. I would first make sure that your pH is actually at a point where its going to cause problems (below 7.7) and if that is the case, you would likely be better off looking at adding kalk to your top off.

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On a side note, frustration led me to have a duh moment, and I decided to test my tank water with the test kits I used prior to my Neptune Apex with Lab Grade pH probe.

 

So to start with, my Apex had my tank water at a 7.47 pH. Now comes my test kits, both of which don't expire until mid 2015. I ran two tests per kit (API and Salifert). Both times I got a reading of 7.8 by API (although it could have been 7.9 if I really wanted to nit pick). And both times I got a reading of 8.0 from my Salifert kit. Neither of these test kits were anywhere near the color for a pH of 7.4. The Salifert has a yellow reading for 7.4 and API has a light orange, and my results via these kits were NOWHERE near those colors.


I subsequently decided to recalibrate the Apex pH probe. I let the solutions of 7.01 and 10.1 sit in my tank water for 15 minutes. I then followed the commands of my Apex display to setup the pH. I even 'rinsed' the pH probe off in RODI water whenever I took the probe from one solution to the other. After calibration was over I put the probe back in each solution (making sure to 'rinse' between). Immediately after calibration the probe was reading was 7.01 steady for a period of thirty seconds in the 7.01 solution (perfect), and it read 9.99 steady for a period of thirty seconds in the 10.01 solution (very good). I then tried to replicate this result once again, and got a steady reading of 6.99 for a period of 60 seconds in the 7.01 solution, and a steady reading of 9.91 for a period of 60 seconds in the 10.01 solution. Assuming these values are still very close to the solution (and taking into account the constant swapping between solutions and RODI water rinses) I figured the probe was calibrated for sure. I subsequently placed it back into my tank and waited 15 minutes for the probe to get settled in my tank after calibration.

 

Fifteen minutes later I checked my display module and see that the probe is reporting a pH of 7.42 (remember, it read a pH of 7.47 prior to this whole re-calibration). So, while its definitely keeping a consistent reading even between recalibration, I just don't understand why its report such low values when compared to my test kits. I'm definitely more confused than before =\

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seems like you would just need to peel a seal off one side of your front door or window or somethin so a little bit of air can seep in.

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jedimaster1138

CO2 converts to carbonic acid in saltwater and lowers the pH. Carbon dioxide build up inside of newer homes/apartments is a real problem. Adding additional surface agitation or a skimmer will not help as you are just mixing more air with elevated CO2 into the tank. Open a window or figure out how to get air into your tank from the outside.

 

Don't chase pH.. but you do need to do something when it's only 7.5 at the end of the day. 7.6-7.8 is about the lowest swing that I'm comfortable with. I'm at about 7.95-8.15 on my larger tank.

 

Quoting this for truth and reinforcement.

 

I don't live in Florida, but I have this exact problem in NYC. My apartment is sealed up tight and especially in winter the pH is dangerously low. By dangerous I mean it falls below 7.80 over night with the lights off. While I agree with everyone saying we should not chase pH, a pH below 7.80 is too low and needs to be dealt with.

 

Just to be clear and expand on the above - the low pH is caused by an excess of CO2 in the air inside your home. It has nothing to do with oxygen. It's all about carbon dioxide which you have an excess of in your home.

 

You can add an airstone, increase surface agitation or run a protein skimmer all you want, but the results will be the same, as each of those methods will simply put more CO2 in the water ...

 

... unless you find a way to pull air lower in CO2 into the tank and/or remove CO2 from the ambient air of your home. Obviously option 2 is difficult as it's summer time and the temperature outside is probably too hot to handle. In my case, it's worse in winter when it's 0 degrees out and I'll be flogged by my always-cold-wife if I open a window to change the air in the apartment.

 

My tank is ~30 feet from the nearest window, so running an air line for my skimmer is a non-starter. I tried the kalkwasser approach and it does help, but as others note, it's not going to be a major swing and you'll notice pH rise after dosing...then drop again slowly. Then you'll find yourself dosing a lot of kalkwasser, or doing so frequently... and then there's the other issue of having to keep a close eye on your dKH.

 

The one thing I can suggest is, and I have no clue if this is possible due to home layout and domestic harmony issues, is opening a window near the tank at night. It might not sound like much, but I noticed a change for the better when I was able to at least crack a window in the living room over night. The wife is asleep in the bedroom then so she doesn't notice the open window as much in my case (though I still get grief if she's up before me and has to close the window)

 

Other wise, if your tank is close enough to a window where you can elegantly run an airline out the window, get yourself a skimmer and run that airline outside. Again, it won't help a ton, but it will help a little. The combination of the new skimmer pulling air from outside and the open window and a reasonable amount of kalkwasser dosing will probably help at least get the CO2 concentration down somewhat, and thus your pH up. I don't think any one of those options will do it, short of being able to open a window fully for > 4 hours a day.

 

PS I did use the CO2 scrubber media in a reactor attached to my skimmer over the winter. It worked great...for about 18 hours. Then the media was spent and the pH crashed again. Good times. I don't know what I'll do this coming winter. I'm kind of avoiding thinking about the issue right now...

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Thank you guys so much for all the help and suggestions. After double checking my Apex readings against two test kits, I believe my problems may stem from the apex prob. I have a support ticket open with them in an attempt to see if the issue is with the probe, given the two other test kit readings.

 

I tested for stray voltage and EMI with negative results. That being said, I ended up cleaning the tip of the brand new probe, and recalculating it. They suggested i wait 24 hours and report the results in the morning. I took very careful, detailed steps while recalibrating. And after 6 hours my prob is giving me a reading of 7.64. Still not what i believe my pH to be, but definitly the highest its ever reported....

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Whether your pH changes from a value depends on the buffering capacity of the water. You buffer the water by adding chemicals like carbonate, bicarbonates, etc that can both accept a hydrogen atom and give off a hydrogen atom to maintain the current pH. Your soda ash from your brs kit is a buffer. The purpose of the kalkwasser is to raise your pH to somewhere between 8.2 and 8.4, being a strong base. When you add the brs soda ash, it's acting as a weak base accepting some hydrogen atoms from the water and that's why you see your pH rise slightly becoming slightly basic. However, it will not effect the same rise in pH as kalkwasser. Just from my observation with my tanks, the pH equilibrium of a closed reef tank seems to be towards pH 7.4-7.6 as you observed in your tank. It's probably due to a net effect of acidic reactions of biological systems such as nitrification and formation of organic acids from metabolic wastes as well as carbon dioxide in the air, esp. in a closed room.

 

To add the kalkwasser, you can place 1 tsp in a 1 gallon jug containing top off water and manually add it to the tank. Add 1/3 and check the pH. Remember to give the inhabitants of the tank time to adjust to the new basic pH before you add more kalkwasser. When you reach your target pH, then buffer the tank with your brs soda ash. I aim for 10-14dkH.

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