Tank tempuratures/PH

L

lmcnutt

All,

I'm in the process of setting up a 90g with a 35g sump. The sump will be located in the garage. Has anyone had experience with the temp fluctuations doing this?

I currently have the sump running (empty) with S/W circulating within itself to acclimate myself to the whole sump setup. I have, again currently, a mag 12 in the sump doing the circulation. When it was cooler earlier this week, I had no trouble keep the temp at 78.5 using 1 200w heater. Now with the temps going up outside, the sump is fluctuating between 81-83 degrees.

Is this strictly due to the ambient temp of the garage or possibly the interal pump. Note, I have the pumps flow retarded a bit. Is that generating heat too?

I realize I'll need a chiller to pull this off in the summer, but I didn't expect it in 75 degree weather.

Also, the PH seems to be on the rise everyday. There is no lighting currently in the sump (again it is empty), but the PH is at 83.3. It has risen from 81.5 in the week I've had it running.

Thanks for your help, sorry for the long post.
Larry
 
The garage is going to very hot in the summer. I have seen our garage get to 120 during some hot days with the sun shining on the garage door all afternoon. I think you are going to have major heat issues during the summer months.
 
The pH is up because you have fresh air in the garage, especially as you open and close the garage door several times a day.

A retricted pump will increase its heat, but the heat and humidity will be what is the real problem.

Putting a fan blowing down on the surface of the water will help, but like Rick said, this summer you'll have to use a chiller with the garage that hot.
 
Another thought about having an open sump in the garage you need to be aware of. Just like the pH going up because of the fresh air raising the O2 levels in the water and lowering the C02. You also need to be aware that any airborne contaminants in the garage will quickly find their way into the tank water through the open sump. Be extra carefull about spraying ay pesticides, paints, or other toxic fumes in or in the facinity of the open garage. That would also include the carbon monoxide exhaust from any car left running too long.
 
I've considered the contamination issue as well. The sump is in a 4' wide cabinet that is 8' tall. It has doors as well. This won't necessarily stop the airborne stuff from settling into the sump, but it'll help. It does, however, contribute somewhat to the heat issue. I will definitely need to add ventilation.

So the PH is the fresh air. That's a good thing right? When I hook a real tank to it, this should, over time, come down? Is there something else I should do to compensate for the high PH?

Thanks!
 
I'm missing the "fresh air" as a cause of increasing pH.

I assume all of our homes have doors, which are opened on occassion, and windows, which leak air and are also often opened.

What is in this "fresh air" in the garage which is causing the pH to increase but does not cause the same (or does it?) when the sump is in the house with my tank?

If he means temp (given the numbers 83.3 and 81.5 - pH is 0 - 14 isn't it) I wouldn't put the blame on the fresh air, but on the stale air.

I'm sure I'm missing something but always manage to learn something new from your responses.

Thanks
 
The response has to do with the ratio of CO2 and O2 in a home versus outside/outdoors. By providing fresh air with a higher O2 and lower CO2 content across water, the amount of CO2 that escapes from the water is increased. As CO2 level is decreased in the water (due to it's escape), the pH rises (kinda the opposite effect of the process in the Calc reactor where you add CO2 to make the reactor water acidic - lower pH - to dissolve the media). By passing fresh O2 rich air over a tank, the pH should increase (all other factors being equal) :shock:

Doug
 
It's the same as today when I have all windows open on the house and cabinet doors open. It helps the cooling and my pH is up a little higher than in the winter when the house is all closed up cause it is cold. Or even in the summer when it is hot. And it only is a pH difference from when a lower pH is a result of excess Co2 from say a tank for a calcium reactor or a buildup of some other reason, alot of people in a closed house.
 
Ok - O is in the range of 210,000 parts per million (roughly 21% of "air" is O) - CO2 in the range of 350 - 370 PPM in the atmosphere (lets skip all the burning fuels, sea level variation, trees, water, cow farts, etc).

Doubling the CO2 PPM in a house is considered "bad air". Pushing CO2 to the 3000PPM range causes headaches and other physical ailments.

So 370 / 210,000 vs even 3000 / 210,000 would seem to contribute little to the variation of pH in 30 gallons of water.

Not sure what the difference in CO2 is between the inside air and outside air in the Plano area but I can assure you Drees does not build a "tight" house and with 3 children and a couple of dogs I get a great deal of mixture between the inside and outside (as my heating / cooling bill will attest) so do not expect the difference is 350 vs 3000.
 
All I can tell you with my tank (just inside the garage door leading to the house), I struggle with the PH constantly being low. I've even posted on here about it. I install a sump in the garage, 10 feet from where my tank currently sits, and the PH is 8.35. On the high side for sure.

One of my follow-up questions was...should I do anything about this high PH or will adding an actual tank in the house with all that goes on there, bring it down naturally?

Larry
 
Personally I would suspect measurement variation based on statements such as the one below from Omega.

Temperature Compensation does not compensate for all factors in pH measurement. Unless your home is maintained at the same temperature/humidity year 'round (and your instrument temp isolated, consistently cleaned, no finger oils on any section of the probe) each measurement includes a number of variables. Tthe instruments we use at this level yield a "best guess" at the given temperature.


From Omega:

The actual pH of the sample can change with temperature due to a change in the hydrogen ion activity in the solution, because ionization of compounds and hydrogen ion activity in the solution may be temperature dependent. Temperature compensation does not correct for this, and is not desirable, because an accurate pH measurement is desired at that particular temperature. Temperature compensation only corrects for the change in the output of the electrode, not for the change in the actual solution pH. Temperature will also affect the glass membrane's impedance. For each 8° below 25°C, the specified impedance approximately doubles. Depending on the original impedance of the glass membrane, the meter will have to handle a higher impedance at a lower temperature.
 
Is this sump sitting in a hot garage and it is not connected to anything?

Is water evaporating?

When you say the tanks in your house have "low" ph, what is low? Does the pH continue to drop? Bio-load? Top off water parameters?

I've only been back in this hobby for a couple of years. I have 6G to 100G tanks. I just don't see wild variation in pH in any of them. Salt? Sand? Load? Rock? I'm missing why I'm not seeing issues unless my yardstick is shorter than everyone else's.
 
Mark

I think that was the point. 350PPM atm and some multiplier higher indoors (usually way higher in offices, schools, malls).

While it is also true O2 % may also drop in a closed up home I'm still not seeing the ratio variation as sufficient to impact the pH of even small amounts of water.

Enough said. I'm not sure why his is creeping up or down. All of mine stay reasonably consistent with temp variation as my answer (and water chagne time) for why I might see a .1 .2 swing.

When the indoor temp is consistent, so is my measured pH.
 
The garage is not necessarily hot right now, but boy just wait.

Yes, it is in the garage and not connected to anything. Just circulating.

Water is evaporating at I'd say 1 gallon/day.

Tank in the house has been as low as 7.8 (at least by my guess on that crummy tester). Today I think it's at about 8.1. It's 29g and has plenty of rock, sand. 5 fish and a shrimp, assorted clean-up. I've always attributed the low PH to fresh air. I don't have a good skimmer on it either. It's a simple Red Sea air stone type.

Thanks for the great discussion.
 
I heard that on the crummy tester. $100 does not go as far as used to and I can't make myself buy a $500 Hanna or Extech like we used at the power plants. Someday maybe.

I don't know how to verify it is location specific without moving the sump into the house where the air isn't fresh (not the bathroom, somewhere like the tornado hidey hole).

Adding the pH Up/Down chemicals is just outside of my realm. I have a difficult time adding any chemical - even the stuff I know the tank needs. Something wrong when "living better chemically" extends to my tanks.

More discussion of what is causing it than how to fix it. Probably not too helpful in the long-run.
 
My wife just got home from work and is wondering why I am trying to heat the house to 120F.

I don' think she is finding the experiment at all acceptable.
 
I think that was the point. 350PPM atm and some multiplier higher indoors (usually way higher in offices said:
Since RC yanked my graphic (grrrrr), the image was of pH vs. alkalinity for two different ambient levels of CO2 - one for 350ppm (outside air) and one for 1000ppm (a common indoor number). The image I linked to is in this article about a quarter of the way down the page:

http://www.reefkeeping.com/issues/2004-09/rhf/index.php

While it is also true O2 % may also drop in a closed up home I'm still not seeing the ratio variation as sufficient to impact the pH of even small amounts of water. said:
Common misconception - ratio of O2/CO2 doesn't really have anything to do with pH in the ratios they occur in the atmosphere. Henry's Law states that the solubility of a gas in a solution is related to the partial pressure of the gas above the solution. Assuming a pressure of 1 atmosphere, we have partial pressure of O2 (pO2) staying almost constant in terms of % change, while partial pressure of CO2 (pCO2) changes tremendously (300% of its original value compared to 350ppm). So dissolved O2 will remain essentially unchanged, while dissolved CO2 will almost triple. Once in solution, CO2 combines with water molecules to form carbonic acid, H2CO3. Carbonic acid dissociates into H+ and bicarbonate (HCO3-), lowering the pH of the solution. Tripling atmospheric CO2 levels = tripling carbonic acid levels. Blowing off this excess CO2 is difficult and is the reason why people who run calcium reactors (which use carbonic acid to dissolve calcium carbonate) tend to run with low pH. Likewise, kalk reactors require the absorption of atmospheric CO2 in order to make the hydroxide from the kalk (calcium hydroxide) dissappear in the carbonate/bicarbonate system. Since equilibriation with atmospheric CO2 is slow, kalk reactor systems tend to run at high pH (since that excess OH- just pushes pH up until it finds some dissolved CO2 to react with).

(I'm an amateur chemist here, so take all this with a BIG grain of salt).

Now, none of this really means anything with regard to the original question. All we know is that his pH and temp went up over the course of a few days.

The temp I would totally attribute to the mag 12. Those things run at over 100w, and unless ambient temp went over 80 degrees, there's no way your sump would break 80 degrees (granted I have no idea what temps have been like in DFW or your garage for that matter - I'm in Bryan at the moment). Heat always flows from hot -> cold. If your garage is at 75, then your sump is heating your garage, not the other way around. Humidity, airflow, etc is not a concern.

The pH I have really no idea about. If it had excess CO2 in solution, as it might have had if the water had been stored indoors before being moved to the garage, then blowing off of the excess CO2 in the lower-CO2 containing outside air might explain the increase. But given that it's relatively fresh salt mix, it might just be the salt mix itself aging and equilibriating. So long as it sticks around 8.3 I wouldn't really care what it does.

Now about the temp - I'm not familiar with pH fluctuations in seawater based on temp. I understand that seawater pH is a little more complicated than freshwater pH. But I would very much discount the influence of water temperature on pH regardless. In pure water, H2O dissociates in to H+ and OH- to a very small extent.

H2O
<hr class="bbcode_rule" />
> H+ + OH-

How much dissociates is dependent on the equilibrium constant, K, and is given by this equation (things in brackets denote molar concentrations)

K = [H+] * [OH-]

K is dependent on temperature. As temp rises, K increases. As K increases, so do the concentrations of H+ and OH-. Now, a neutral solution will remain neutral as temp rises, since there are equal concentrations of H+ and OH- ions. But, as temperature rises, pH actually decreases (since pH = -log[H+]). So it is entirely possible for neutral water to have a pH BELOW 7.0. In fact, neutral water only has a pH of 7 at 25 degrees C (77deg F). At all other temperatures, neutral water has a pH that does NOT equal 7. Not really germane to the conversation, but an interesting factoid nonetheless.

Now, this increased dissociativity of water into H+ and OH- wrt temp is really really minor. This minor increased dissociativity is what Omega is talking about when they say

The actual pH of the sample can change with temperature due to a change in the hydrogen ion activity in the solution said:
Now when Omega is talking about this:

Temperature compensation only corrects for the change in the output of the electrode said:
they're talking about how the actual meter responds to temp, not how the solution pH responds to temp. It sounds like the meter's response wrt to temp can change a lot (something I did not know :))


Again, amateur chemist here and all, I am no Randy Holmes-Farley, so anyone feel free to correct me in case I am horribly wrong somewhere (which I may totally be - I dropped O-chem twice :))
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I'm just a hobbyist, but I've read enough of Randy Holmes-Farley's articles to know that excess CO2 in the water drives down pH levels. Providing fresh air removes excess C02 from the home, and thus from the tank as well. Fresh air is drawn in via the skimmer, for example... instead of more CO2-laden air.

Easiest test: Take a cup of tank water, measure the pH. Take it outside, hook up an airstone to a pump for 30 minutes to aerate the water, and test the pH again. Typically it is higher.

I know one of Randy's articles he tested CO2 in the room based on several factors, including just leaving his dog in the room to see what would occur. Then he had a room full of people, and the numbers really increased (CO2-wise) and pH plummetted. When no-one entered the room, the pH stayed higher.

Btw, it is pointless to debate this with me, because I'm not the expert. All I can share are my own personal experiences and those are these: Whenever the home can be open to fresh air (12 weeks a year, I'd guess), pH is higher in my tank (around 8.2 to 8.3) and the rest of the year it is 8.1 at the peak of the day. I've considered running some air from outside into the intake of my skimmer just to provide fresh air year round.
 
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