Hi,

Temp is around 78 F. My tank is predominately softies and some LPS, so lower temperatures seems to be better for these types of corals. During the summer, I raise it to 82F because the weather automatically brings all of the tanks to 82 +/- 2 F. However, my corals are not so hot doing the summer and their growth slows down by half or more. There is a dependence on growth rate and temperature with some corals -- some do better at high temperature (I think some SPS) and some do better a lower temperatures (mushrooms). RC might have more in depth discussions on this topic.

Reef_raf,

Yes, pH is temperature dependent. However, the pH test probes (the ones based on Ag/AgCl -- most common type) also have temperature dependent errors. You'll need to calibrate the probes to see the true pH dependance on temperature. I don't remember which direction it is suppose to move...but I think it is lower pH for higher temperatures.

- Victor.

Victor, lower pH with higher temp makes sense. O2 is less soluble in warmer water, and I believe this gives CO2 the oppurtunity to "move in". Not sure of the salts used in my probe (probalby AgCL) but it is an ATC probe. Temp shouldn't need to be calculated for it. I'm just wondering if I drop my temp 2 degrees, will it boost the pH? Steve is going to "test" this for me.

Co2 and O2 don't displace each other.. lower temp water just allows more to be desolved in it.. sence O2 doesent affect PH the theory SHOULD be that PH will decrease with lower temps as it will be able to hold more C02.. but by the same tolken, colder water will alos alow more of other stuff to be adsorbed which could "Buffer" the water to some degree.

Steve

Alas, my young chemistry friend, that is why I asked you to test it. I'll expect results tomorrow, K?

Hey Stir- does this mean that if I had a temp. gain of 1 or 2 degrees on a really hot day, would I have to re-calibrate my pinpoint every time I have a temp. increase or decrease :?: :? :) sff

nope, they should be tempature compensated. they don't give you a real PH reading persay but rather a "adjusted to 60 deg" PH reading.. or what ever temp they are compensated to..so that means that if you use a test kit and a digital they can and most likely will be different readings as the digital will be temp compensated and the value showen would be the PH of your water at a spicific tempature where the test kit would show the PH at the tempature of your sample.

clear as mud?

Steve

Thanks Stir-I learned something new today :wink:

There's way too much going on in a reef aquarium to directly associate pH with the solubility of gases in the water as affected by temperature. For one thing, lowering the temperature of the water would likely cause the metabolic rate (the sum of the catabolic and anabolic reactions) of all of the cold blooded animals in the aquarium to decline - for example: aerobic respiration would likely decline, and if you consider that one of the primary components of aerobic respiration as well as photosynthesis is an increase in the H+ gradient which is used to fuel ATP synthesis, and that pH is a measure of the hydronium ion concentration, then it simply makes sense that the lower temp will have an effect on the metabolic reactions of the organisms within the aquarium, and thus have an effect on the pH.

Among other things. And I fully acknowledge that the above is a gross simplification of things (like the fact that cell membranes and their permeability would have significant effect).