Hey folks. Currently in a new, larger setup and wrapping up the first grow- three ladies in 5 gallon pots. Also have a larger container garden with fruit and veg outdoors this season. Generally more plants than usual. A very welcome change With more plants comes more water. Instead of correcting each gallon I've began to correct 5-10 gallons at a time in two plastic buckets, and fill my watering can/sprayer as needed. The plastic is type 2 HDPE, very unreactive to harsh solvents and water. Supposedly. Apparently HDPE is acceptable for long term storage of -drinking- water as long as it's "FDA-approved, food-grade, BPA-free virgin polyethylene resin, that is also: ANSI / NSF 61 approved for potable water applications". Those could simply be liability statements or there could be underlying chemical reactions occurring. Anyway, here's how my readings change pretty significantly over a few days to a week in storage. Tap pH/ppm out: 5.5/100 Corrected pH/ppm: 6.3/200 pH/ppm after storage: 5.5/180 Now keep in mind, I add pH up prior to filling container, and take readings immediately after and an hour after mixing. So.. what the fuck? CO2 and O2 can both dissolve in water. Oxygen is not very soluble at all and once dissolved, takes a very long time to associate back into O2. CO2 is more soluble and is notoriously effective at acidifying water. But what would be in my water to do this? The acidity/alkalinity of water is determined by the concentration of H+ and OH- ions. Since my water is acidic, and is actively reverting back to an acidic state, something is present to donate more and more hydrogen atoms. The reaction between K2CO3 and H2O results the production of OH- ions. Something is reacting with the OH- to create water and an extra hydrogen as a result. Water as a byproduct could decrease the TDS within the solution also. Another possibility is that I'm inaccurately reading pH and TDS. I think it's unlikely, but I'm buying a new meter to be sure. I doubt there will be a significant change in accuracy. Perhaps there are molecules that take a long time to fully dissolve in the water. I'm thinking it may be plastics from the bucket. But there's also a possibility it's heavy metals from the pipes in my building. This is what I fear the most. Suspended particles of heavy metals that take a long time to react with the water in their respective molecular states (since most don't dissociate into elementary ions in water). When I moved into my place, I was notified that there may or may not be lead pipes in my building. Not really sure why they don't have to test and confirm this, but I'm worried. I learned that lead (and other heavy metals) form carbonate compounds which can acidify the water. Having a low pH can also make it more solute than neutral water would be. Good fucking God. I already filter my drinking water but it's going to be expensive to manually filter tap water at the rate I need it. Speculation aside, what do you use to store your water? Do you notice TDS and pH changing over time? Have you experienced anything like this?
hey.. make up 3 gal for 3 days at a time and let it bubble overnight (air stone). I have to add ph down most times (not always though) and notice the next day, I get a higher pH and EC. I imagine that the carbonate takes time to react (increasing the pH over time) and that some of the water evaporates, but maybe somethign else going on. Also, pH 5.5 will breakdown your building's pipes. I would recommend adding some calcium carbonate (or dolomite lime) to increase your water's pH, maybe even grab some filters. You can now re=mineralize your water after RO, which would be adding the carbonate. pH 5.5 should be unacceptable for drinking water, it will dissolve your metal pipes over time (as you suggested).
Thanks! Why 3 gallons specifically? Shouldn't I be fine with my two 5-gallon buckets? 5.5 is absolutely breaking down my building's pipes. Drinking it is terrible, turns my insides to fire. I don't know how it's legal to be honest. One look at the Bay tells you how much Maryland cares about quality of environment. But the TDS out the tap always reads 80 to 100 ppm. Absolutely strange. At that point I don't think there's many minerals in the water to begin with. I use pH up which is potassium carbonate, any reason you recommend the calcium carbonate over it?
Oh I was just saying for me I use 3 gallons each 3 days for the one plant and reported back the numbers. I imagine KCO3 is fine, as long you keep a 4:1 ratio of calcium:magnesium otherwise you could face some calcium issues down the road. I thought I was using KOH for phup, might be a better way to deal with dropping ph later on when u introduce bloom nutes. The new filters that are out, sure they don't last as long, but they are pretty cheap (>$100) and can really eliminate a lot of unwanted crap from the tap without needing to waste water through an RO. That's the main reason I don't use my own RO system, but if I do upgrade, I will be using the special pumps to decrease. 5.5 ... I would be outside their main office protesting. On the other hand, if you ever decide to go hydro, you will be set (since the pH of hydro plants is 5.5-6.1 range. Also, I run my coco at ~6.2, but the runoff is horribly low sometimes depending on what nutes I use. Last thing I can add, instead of using pH up or remineralization, you might consider changing the nutes and using somethign with more ammonium in it (for a nitrogen source). I will attach a relevant .pdf for you to look over.
I'm still using the pH up I mentioned in the last post you helped me with mate, just trying to work with what I have at the moment Dude, wow. Cornell consistently fails to disappoint. What a great source of info, I've already downloaded it lol. So nitrate is better stored, raises pH, water soluble. Ammonia base lowers pH and is (mainly) responsible for plant damage in excess. Fascinating. I see what you mean about the 3 gallons thing. Thanks for clarifying. Also, is the filter really necessary if my ppm out is 80? Okay, maybe not necessary considering the plant's a bloody weed and will thrive in most conditions, but I think you know what I mean. I've always been under the impression that 80 is low for city tap. In fact I've been worried about micro def's because of it. I also ran a little experiment on the water. Kept a glass jar of straight tap water, a glass jar of pH'd tap water, and the big bucket of pH'd tap water. Took readings last night and this morning. The pH'd water changed from 6.3/6.4 to 6.0/6.2. Regardless of container material. So you'd be entirely right in saying the K2CO3 takes a bit to react. I'm actually surprised, not only did my hydro store lie to me (yet again) but I totally underestimated the rate of reaction. I'm so tempted to send my water off to a lab to get spectro'd. At this rate, I might as well go to hydro. I've been avoiding it but it'll probably be something to consider in the next year or two.
no it shouldn't need anything, although I would still use ro/distilled/mineral water to start plants (and seedlings). you should be able to access the Water Quality Report from your municipality's records. Mine are posted online, but you can just call {your waterworks company} and ask them for it for free. I have less problems in hydro than soil and coco. Once people in hydro, I don't see many go back. Can start easy with some bubblers to get the hang of it. Maybe check out my aero thread, kinda innovative and good to get some ideas from.
@Mr. Handy The pH of an aqueous solution will change as temperatures increase and decrease. The single only other thing that would cause it to change would be the type/quality of the storage containers. j
Well, fuck. After a nice fat dab and a little bit of garden maintenance I've now got some interesting reading material. If you don't mind, I may inbox you a few more questions regarding this stuff. Definitely going to check all this out. pH does change temperature but only nominally so. You also wouldn't be watering with freezing or boiling water. This: (Temperature Dependence of the pH of pure Water) gives a bit more of a breakdown, in which I would expect to see at most a .2 change in pH under my conditions. Also, as a control, I've taken pH readings with cold, room temp, and hot tap water, all with the same result. Only difference is the ppm roughly doubles between cold and hot. Temperature of water doesn't impact the concentration of hydrogen in the water, merely the effective rate of its reaction. At the end of the article you linked, the researchers acknowledged this and said that at 100 C, the pure water will have a 'new neutral' of 6.14. If I flushed with water that's 15C vs 30C (ignoring potential root damage) the pH of the medium wouldn't change because of this. I do like the comparison between water/acid/base with temperature change. Interesting that an acidic solution is more likely to remain acidic and a basic solution is likely to increase acidity with temperature. There's a few discrepancies which should be noted from these studies too. They used pure water, which is much more susceptible to pH fluctuation as it's entirely comprised of the base molecules that determine acidity and alkalinity. I always appreciate the scientific discussion, helps us all learn
I was calibrating my meters yesterday and double checked the temp/ph table on the packet and have to agree, there wasn't too much there for concern. But I will add that I think it should be considered when calibrating the pen, so I do heat the solution to 25C (ok I didn't check last time, but heated it a lil). Also, idk if this is true, but I use two cheap ph pens to measure, and I notice that they get flaky results sometimes. They will be within 0.1 range normally when I make up solutions, but when I check my cooler (~18C) reservoir, there is a greater delta difference, maybe even 0.5 and I've always wondered if its the temperature causing this difference. I should check (next time I calibrate). You can pm me anytime bro.
I can tolerate a .1 difference. Ideally my water will be in a safe enough region to handle a .1 variation. That's the grain of salt I take with electronic equipment. I'm not paying for lab grade stuff, but I don't need lab grade readings. However... 0.5 is definitely concerning. I agree with getting all the variables down when calibrating. Even though the cold res reads adifferent pH, have you ever noticed it changing your coco pH?
When all is calibrated the two cheap pens work fine, and 0.5 is maybe an exaggeration. The thing is though, its really important for me to use two cheap pens; can get some nice self-calibrating ones for cheap. If the delta starts to get too large, calibrate. But how would u know if you only have one pen? I've also marked a pen recently to be able to distinguish if one of them is going out more often, and then I can decide if its time for a new one, but these last ones I got seem pretty good, but I do calibrate them and store them in KCl sometimes (usually prior to calibration). I purchased one in Sep and one in Oct. note in CAD$ not USD. If I were to spend more for a pen, it would probably be an Apera or BlueLab.
I've actually heard a few bad things about BlueLab... enough to make me second guess buying one, despite its rep. I'd like to go the cheaper route and buy a meter that does both TDS + pH but it doesn't seem like there are very many. Probably just going to do what you're saying lol Also is KCl how you're supposed to store meters? I've never really known
If you add 225g of KCl (potassium chloride) to 1L of water (ro/distilled) you will have 3M KCl solution = storage solution, which should last you a lifetime or two. Can buy KCl on amazon. I don't always store it in there though, just before I calibrate seems better imo, since the K+ may differ in the probe (?) Oh, I noticed a 0.2 difference in the calibration of my reservoir today. It is ~15-18C. I also noticed this difference when making up my other 12L mix, but noted that I used cold water. It was not 0.5, that would mean calibration time.
Is your container ever in direct sunlight? Again with the plastic container... another consideration - do you NEED to store your water? j
just took this picture, idk how accurate any of that info is though. I can live with 0.2 delta error. I prefer it to be within 0.1 though.
I know, both articles are using the same data for distilled water. That's just the grain of salt I take when speculating on how drastic of a fluctuation I would expect from temp. I think that's the closest data we'd be able to find without breaking into the actual chemistry etc etc. Never in direct sunlight, just in a room. And do I need to? I'm honestly not sure, that's kind of what I'm trying to determine from this. I can use up to 20 gallons when I need to water all of my plants, usually at least 8 to 10. If my largest container is only 5 gallons, and I have two smaller 2 gallon containers, that's 9 gallons at a time if I'm avoiding storage. But usually some gets stored anyways since I don't use it all. If something is polluting the water and bringing its pH down, then I'd rather prep the water as needed. But if the buffer needs time to fully balance, then I know I want to prep water a day or so before using it.