Tropical Fish Forum
Tropical Fish Keeping => General Fishkeeping Chat => Topic started by: Helen on April 08, 2018, 11:43:04 PM
-
Does the temperature of the water affect the pH reading? My vague chemistry understanding suggests yes, but does it need to be significant to be visible?
I ask because my tank pH is a little higher than I'd like it. I'm still getting to grips with calibrating my Seneye, so I'm not certain that this isn't the cause. But I've also noticed, this evening, that the average temperature on my tank has gone up by about half a degree.
I know that this kind of accuracy is only possible because of the Seneye, so I'm not really worried about my fish.
What I have wondered is whether it is the first sign that my heater is on it's way out. My worry is not helped by the realisation that I forgot to turn off the heater when I did a 40% water change yesterday. The Seneye trace suggests that I may have got lucky and the heater didn't turn on while the water level was low, but the two units are at opposite ends of my tank, so it's not an overly reliable source of information.
So back to the original question, if I tweak my heater down half a degree, will that make a difference to my pH?
-
I can't answer that with any authority H, but it would be hard to imagine a 0.5 degree difference having any bearing...
-
Well, knock me over with a feather... Just found this:
Temperature plays a significant role on pH measurements. As the temperature rises, molecular vibrations increase which results in the ability of water to ionise and form more hydrogen ions. As a result, the pH will drop."
Taken from: https://www.westlab.com/blog/2017/11/15/how-does-temperature-affect-ph
Still can't imagine half a degree Celsius making a measurable difference, but ya never know...?
-
I actually had the concept of ions at the back of my head, when I initially wondered about temperature.
But my half a degree is definitely not correlating to my pH. My pH is higher than expected. According to that snippet (which makes sense to me) my pH should be lower.
I have to say, that although I love the detail that the Seneye gives me, having it has significantly increased my stress levels! I see patterns and variations that I never saw when I was reliant on my analogue stick thermometer and liquid tests.
-
Just had to dash off to Google to see what the Seneye is... Hadn't heard of that before... Looks great, although I can easily imagine that unwittingly increasing stress levels... Was it expensive Helen...?
-
My Seneye was a gift. But I don't think they are cheap. I keep looking at the webserver and WiFi unit so that I can have it permanently hooked up to the web. (I can check my tank from work or my bed!). But I am struggling to justify the +£150 price tag for what is, essentially, a nice to have. At the moment, I upload the offline readings every so often (every 1-2 weeks, unless there's something going on). There are lights on it that tell me if the readings are outside the parameters I've set, without having to connect it to my laptop.
Really, the only readings I use are the temperature and the pH. The ammonia has too little visible variation (as you'd expect for a mature planted tank) and the other chemical readings are calculated, rather than measured. Except for the light. As I have LEDs, the colour temperature readings don't work and my lights are on timers, so the total lumens doesn't really tell me anything I don't already know. And I don't consider it a disaster if my lights don't come on. The thing that is interesting is how low my light levels actually are. But my plants are ok with that, so I don't worry.
-
For what it's worth, I'd say this: with having a love for fine wine, I think spending that sort of money on something that represents a passion for you and especially with having an analytical outlook, is easily justified... There's no doubt you would enjoy it (stress aside, lol) and more importantly, would use it/refer to it frequently...
-
Temperature does affect pH but not significantly enough for us to detect in tanks. By the time we could measure a difference in pH the temperature change would have killed the fish. We work in a very narrow temperature band.
-
From the Seneye readings in my ‘pond’ it appears that my pH rises with an increase in temperature. This seems bizarre to me as I also assumed the pH got lower as the temperature rises. The NH4 levels seem to abide with the rules (pH rises NH4 levels decrease). Free ammonia readings, however, are stable at 0.001 ppm.
I’ll grab some screenshots of the readings later so you can see what I mean.
-
These figures are for pure water, though our tanks are not pure water:
20oC - pH 7.08
25oC - pH 7.00
30oC - pH 6.92
In chemistry, every parameter is quoted at STP - standard temperature and pressure. Pressure is 760 mm mercury and temp is 25oC or 298o absolute. This is why the pH of pure water is always quoted as 7.0 - that's the value at 25 C.
Using just test kits, liquid or strip, the variation is too small to detect. i have no idea if Seneye is sensitive enough to detect this small a variation.
-
Here are the screenshots of my Seneye readings from the pond. I have included Temp, pH, NH3 and NH4.
I have used the last 72 hours as the temperature has been increasing with the sunlight. The heaters haven't "kicked in" either over this period.
-
I’ve just had a horrible thought. The Seneye is quite close to the water surface and angled towards it. I’m wondering if bright sunlight has been affecting the sensors. I have moved it lower in the pond in order to rule this out.
-
I wouldn't have thought that the sunlight would effect the Seneye unless the sunlight actually has a thermal effect on the water. I think this because the Seneye has light sensors in it. I don't know whether the software for the pond version will have these turned on or not.
What is really interesting to me is that your trace looks rather different to mine. Do you have it connected to the internet all the time or do you upload offline readings?
-
Yes it’s permanently connected via a Seneye Web Server. It was originally in my planted tank but I relocated it to the Pond as it’s more susceptible to problems.
-
Seems sensible to put it in a new 'tank' when setting it up. Especially something like your temperate pond.
Do you have the WiFi unit with the webserver, or have you been able to hard wire it?
-
Yes Helen, I am using the WiFi unit. It’s a standard adaptor (Edimax N300 range extender) with a single network port.
The SWS was originally connected to a spare network port on my router until I relocated it to the Pond.
I would say the SWS would be better hardwired directly to the router if that’s feasible.
I have the occasional dropout using the adaptor, but it’s a fair distance from the router (about 50 feet).
-
After doing a bit of research it appears that photosynthesis is the main cause of increases of pH in Ponds. The increased plant/algae growth due to natural light depletes the CO2 causing a rise in pH.
If this is the case shading the Pond during peak sunlight hours should help alleviate this or increase the stocking level to produce more CO2.
I must admit that I can’t really see that this is the cause in my case. I haven’t got a profusion of plants.