Hey all, I am not a first time grower. I have successfully had bubble bucket grows in the past but I am by no means seasoned. But this one has me perplexed. I am about a month into my grow and what I usually do is drain and flush my reservoirs every weekend and fill back with fresh water and fresh nutes. I dont know if this is typical or even a good/bad idea its just what I have always done. Anyhow... what I have noticed the past few weeks is when I change the reservoirs the plants immediately perk up, the leaves reach for the lights and they look really good. By about 4-5 days in between water changes they start to relax and droop a bit. So I decided to investigate... before I changed out my reservoirs I took a sample and I found that the pH of the water was almost 6.6!!! I fill at roughly 5.0 to 5.2 so clearly something changed.... continuing my investigation I just changed out the nute solutions yesterday and here is what I have found I filled 2 reservoirs at 5.1 pH Reservoir 1 - 5 month old plants - pH is 6.45 Reservoir 2 - 1 month old plant and 3 seedlings - pH is 5.6 I have a high quality pH meter that I made sure to recalibrate and verify these readings. So there is not an instrumentation error. So its a fact... in about 30 hours one of reservoirs increased pH by almost a full point and a half. Wow So FINALLY.... to my question. What is causing this pH rise in my soltuion? Is there some biological condition that accounts for this? Do I need to be concerned? Or if, I can do better, then how? Any help is greatly appreciated. THANKS! P.S. I dont know if this helps. But my water here is VERY alkaline, comes out of the faucted at a high 7 or 8 usually, one time it got up into the low 9s. So I have to add quite a bit of pH Down to get to a pH of about 5.1 (usually about 1.2 mL of pH down per gallon water). And no im not using water straight from the tap... its filtered and then allowed to sit overnight I mix up a nute solution.
Are you using hydroton? If so do you rinse them, and I mean good? Did you soak hydroton and air stones in ph'd water? I had the PH rise issue and did none of the above. Once I did them my PH stayed in range. I also believe you want PH to float from 5.8-6.5. I am by no means a pro. Just sharing my experience. Sent from my LGLS740 using Tapatalk
When mine spiked like that it was right before bad bacteria caused root rot. What is your res temp? I wash and boil my hydroton between grows so I ruled that out And yes keep ph around 5.8 in hydroponics
There are many different approaches to topping off reservoirs. I personally have found it most effective/efficient to top off daily with ph'd nutrient solution. For instance: I first test my res solution and compare it to where it was the day before. If TDS rises more than 50-75 points, it signifies that the solution is too strong and the plant's taking up more water than food - a subsequent drop in ph may also be exhibited due to the plant taking up more water and further concentrating the solution (there are other factors, such as ion exchange but we shouldn't get into that just yet). So if my reservoir is say, 5.4/850ppm (.5 conversion tds meter), I'll make a gallon of solution at around 6.5/500ppm to raise the ph and lower the tds. You'll have to experiment with different topping mixes depending on the size of your reservoirs etc.. When I'm done I always take a finish reading (wait a few minutes for the res to balance), and compare it to my reading on the next day. This will show you what the plant is doing in terms of water and nutrients, and help you to decide on the parameters for the next topping. As I briefly touched on, ph swings are a normal part of hydroponics. If more nutrients (than water) are taken up by the plant, the base water's ph will become more apparent and ph will rise, while TDS will fall. If more water (than nutes) is taken up, TDS will rise, and ph will commonly drop as the solution concentrates. This all leads to one goal, finding the "sweet spot" for each plant you are growing. The sweet spot is the optimal TDS value for the particular variety you're working with. When you're at the sweet spot you will have slow/small rises in ph and small drops in tds as the plant takes up water and nutrients at a more equal rate. Keep in mind, strains will differ, and even phenotypes from the same strain will differ in terms of their "sweet spot." I noticed that you said you change your solution weekly; only because of the weekly changes have you gotten away with not testing ph more frequently (daily until you really know the strain you're working with). With the method I use (I surely didn't invent the method, many others on here use it), you don't have to change out the res except for transitional periods (veg to flower, flower to flush), and maybe once halfway thorough flowering if you're having any issues with decomposing root material causing swings in ph (3 res changes total- for the plant's entire life-cycle). Also keep in mind that temperatures will play a role in uptake as well. For instance: a plant that's growing in an 86F degree environment will take up much more water than one that is at 76F Degrees. The higher temps will also increase the chances for nute burn due to all the solution that it will be using (use a weaker solution). Light intensity will have a similar affect. I hope this wasn't too confusing, and helps you out some.
btw: I think you mean it rose by 15 points? Keep in mind 5.1 to 5.2 is 1 point. It sounds like your solution is too weak (see above explanation). What's the tds reading (ppm or ec)?
First, 5.1 ph is too low. 5.5 to 6.1 is where I want my PH with 5.8 the sweet spot. Second, check the PH daily and adjust to proper level if it changes Third, weekly res changes are good I find ph increases are an indication the nute strength may be too high. Try cutting back till ph stabilizes. When I hit the right nute levels the PH remains stable for days
Guys... Thanks so much for the helpful responses. Let me take a bit to try ans answer all that I can... and I have a few follow on questions based on the responses. A. Yes I am using Hydroton and air stones (obviously on the last bit) and yes they were rinsed, and pH adjusted before use. I rinse about a gallon of hydroton in 5 gallons of water and flush 3 times and then perform a 1 hour soak with the airstones at proper pH, adjust again and let sit for one more hour. I think thats sufficient. If im in error please advise! B. As far as res changes go.... my experience has been (especially early on like I am presently) in the past to add nutes too often and create a burn and draw the need for a full flush etc. What I believe to have happened is that the nutes in the res werent fully consumed before I added more but thats only notional. I have no information thats what actually took place, but if perhaps my pH target was off one nutrient could have built up to toxic levels rather than being consumed. So this may explain the points made in reply, thank you. In any case, it has been easier (and safer) to make a fresh mix and start from there, albeit a pain in the ass. More on this with my questions later on. C. Yes Im not sure I spoke correctly about the pH vernacular. Sorry about that. D. I have been taking semi daily pH measurements and noticing an immediate rise the day after I changed the solution and a steady state in a few days. I havent taken any action on this because I am not sure of the cause. And i dont want to make it worse hence my ask for help Follow on info and questions.... This is a grow from collected bag seed over a period of time. So strain specificity is out. I havent even sexed them yet. I am growing 2 plants per bucket, they hold 14 gallons of solution each. My water that i use is carbon filtered (brita) but it comes out of the tap at about 500 ppm and 8-9 pH. I add nutes below what the manufacturer recommends because at those levels it burns my plants. However, it dosent change my TDS very much. For example if it comes out of the tap at 450 ppm and I add 20 mL of nutes to 7 gallons the TDS only changes to about 550 ppm. More on this in a sec. but if my starting water seems to be a big problem I can get a bunch of distilled and remix a new batch and maintain it properly. if thats the recommended approach please let me know Here are my questions: 1. Could light leaks cause a pH rise? In my scrutiny of the issue I found a few areas that may be a small light leak and blocked them. 2. How should a bubble bucket be properly maintained? I realize this is probably a long response. but I would really appreciate some input / guidelines. When do you drain / flush? How is it maintained properly? Add water when needed, flush weekly, flush at A B C, etc) Any feedback on this line is greatly appreciated. Certainly when to add nutes is key 3. Is there a guideline for TDS by age? 4. Tips for sexing the plants? Should I take a cutting and root it in an Aerogarden under 12/12 until it flowers? Or 12/12 the entire grow and reset back to an 18/6 veg. Ive done both before and havent noticed a benefit one way or the other so im not sure the best way to proceed
It sounds to me like you have infected roots already, the immediate rise can be caused by bacteria or algae. Light leaks will help the algae for sure. I'd start by adding some h2o2 to the res, it'll take quite abit to get rid if the problem if its an infection. Do you smell anything suspicious when you open the lid? My wife has a much better nose than I and has detected problems days before I could smell anything, so maybe you can ask for a second opinion on that one. I have really hard water and bacteria, before I started using RO I had endless problems with root rot, usually after a week or two, and no matter the reservoir changes, I was always re-introducing the problem...