Two things have been consistent up to this point with the PH problem.
any aeration in the rez made the PH go up. More aeration = faster PH rise.
Putting the nute mix under pressure also made the PH go up. It went up even faster if there was trapped air in the system.
Im now wondering of its the same mechanism working in both situations.
What if aerating the rez made the PH go up because it was making or letting the zombie crap grow faster? That faster growth equaling faster PH rise for what ever reason.
The same mechanism may have been happening in the pressurized parts of the system. Any air trapped in the system would super saturate the solution, and maybe that was enough to make it grow faster the same way it did in the rez?
Thats the best thing I have been able to come up with so far. Actually, the only thing that even remotely fits the facts and seems vaguely plausable.
Wow. Some good news on PH for a change. Im not sure how to act!
Its been 12 hours since I set the PH in the clean rez to 5.6ā¦ This morning all parts of the system are STILL AT 5.6!!!. Actually, I think the rez is starting to climb just a bit - it took the meter close to a full minute to stabilize at 5.6 and it was flickering to 5.7 for a good part of that time. I have been expecting that though - both Mega Crop and Advanced nutes both climb some even when sealed in a mason jar.
It occurred to me that there is another piece of āevidenceā in support of my theory on aerating zombie algae.
There have been several times when the rez was doing well and being somewhat stable, but when I drained some of the accumulator tank water back into the rez, it started to climb in PH again. This was very strong when the accumulator tank was climbing fast and not so much when it was stable. I am now thinking I was re-infecting the rez by dumping infested water from the accumulator tank back in.
Im considering adding a second UV light to the rez. I bought another one of those cheap UV lights to have as a spare because it seemed to be helping keep the PH stable in the rez. But Im wondering if it wasnt quite keeping up with re-infection.
Im going to wait and see how this goes and how lng the PH stays down, then decide. Im 90% sure Im going to keep up the low dose pool shock treatments, but I am hoping I wont have to.
The UV lights have the potential to cause iron issues, but the chlorine kills fuzzy hairs if its too strong - so I dont want to go over board on either if I can avoid it.
Good to know. Iām headed out into the room shortly to do some more cleanup and install more goodies ā perhaps Iāll change up and just do a few hours of flushing the accumulator. I guess I should bring in all of the John Guest fittings and soak them in a good strong solution for a bit before reinstallation.
Glad to hear you seem to be solving the ph issue! Iām getting much closer to starting back up now too, hopefully with a lot less problems this time aroundā¦
I have had to put my PH up to 6.0-6.2 in an attempt to get my plants to absorb Mg. When I did, the humidity increased so I am hoping that is a sign of healthier, more vigorous growth.
They have been at that PH for about 4 days so I am giving them 12 hours at 5.4-5.5 and then I will slowly ramp it up to 6.1-6.2 over 24 hours then let it sit there for a few days then repeat. Two cycles of that, which should take a couple of weeks, and I will refresh the tank.
Interesting. Im glad you posted that. For some reason, I have been thinking that Mg was best absorbed at lower PH ranges in hydro - 5.5ish or so has always been what I have read from growers. But - I just looked at the chart again, and its actually much higher - 6.2 seems to be about optimum for a good balance of all nutes, but Mg likes it even higher.
In fact, looking closely at the chart, I dont see why anyone would want the PH to be as low as 5.5.
Iron, manganese, boron, copper all seem to be better at 5.5ish range, but all the others prefer higher ranges.
So, why have I been fighting so hard to get the PH down?
I know Iāve said this before, but I really feel itās about riding the drift. For me that was an upward drift so I always started at 5.5 then rode that until it was close to 6 then dropped it back down. It just happens that drift time was usually a week, so I only had to lower once then the next week it was res change time and I could reset it.
That looks to be a soil chart. Have a look at the one @SuperiorBuds posted, it has both charts on and if you look at the hydro section, you will see that there isnāt really a single PH point that will provide all your plants need. At least not in the ratios that allow maximum growth anyway. It also shows the P and K lockout in hydro if you let your PH run too high. Also, as mentioned in one of your links a zinc deficiency can happen if you have too tight a grip on PH and donāt let it swing. N, P, K, and zinc all prefer 5.5 over 6, but Mg and Calcium prefer 6 over 5.5ā¦
Years ago I used to run at 6.5, or slightly higher, and I never had any signs of deficiencies and the quality of the end product was very good. Since lowering my PH though, I have seen yields improve, still with no deficiencies or reduction of quality. Only since starting RO have I had any issues, and then it seems only with Mg. Yield and quality are still unaffected.
I have a growing suspicion that the form of Mg in the tap water is bioavailable over a wider PH range than the stuff I can buy in a bottle. I may start doing something I have heard from a few sources now, that being to put 10-50% (the number advised varies greatly) tap water in the tank when I fill it to have a background level of a wide spectrum micronutrient solution.
Duh. I was looking at the wrong chart! I dont even have a good excuse. I wasnt THAT hi, and Iād had my coffeeā¦
Thanks for getting me back on track guys!
Yeah, pretty much everything Ive read says do the drift thing.
I was wanting to build that feature into my planned PH controller - a forced PH swing if it didnt drift on its own.
think part of what got me confused was @MicroDoser said he was raising his PH to improve Mg absorption. You usually see folks saying to lower your PH to fix an Mg deficiency.
Most of the time I see folks talking about the drift happening over several days or a week. It sounds like you are doing a much faster drift up, then sitting at the hi end for a while. Are you seeing significantly better Mg absorption at the hi end then? I assume changing the PH that fast isnt causing any issues?
My entire system is still holding at 5.6 after 24 hours. I can hardly believe it, but its looking like I may have to induce a swing manually. Im debating how fast to force the change - if it doesnt start on its own.
In my case, I dont think I should do something be adding tap water. Im pretty sure its got a lot more of the zombie algae crap in it than can deal with.
You made a comment earlier in the thread about using a cal mag that didnt add excess nitrogen. That sounded like a good idea to me, so I got some CalMag made from Calcium hydroxide and magnesium carbonate. Im not sure I like it. I have no real reason not to as far as the plants go, but two things bother me a bit. For one, it doesnt raise the EC hardly at all when I add it to RO water. I can add 2 ml/gallon and the EC barely changes. However, also unlike the old CalMag, this stuff lower the PH a good bit. A lot more than I remember the GH CalMag doing.
I cant remember seeing any research about different types of calmag being more or less effective, but it seems reasonable that there may be a difference, depending on the chemistry.
It occurs to me that my situation is different from most guys who re-circulate.
When you raise the PH in the rez in a re-circulating system, the roots see that change immediately.
In my system, and to a similar degree in @SuperiorBuds system, when we raise the PH in the rez, it could be many hours before the roots see any change at all. On top of that, they will only see a small portion of the change.
This is because our rez does not directly feed the roots. The nutes are stored under pressure in the accumulator tank. In my case, the rez is 18 gallons, but the accumulator tank only hold about 3.5 gallons of nutes at a time. The reason for the slow PH change at the roots is because the pressure switch kicks on and re-fills the accumulator tank after only 0.5 gallons gets used. So, every time the pump kicks on, its only adding back or replacing about 1/6 of the total volume in the accumulator tank. So, if the PH in the tank and rez starts out at 5.6, and I change the PH of the rez to 5.7, it might be several hours before any of that new solution gets pumped into the accumulator tank. Then only about 1/2 gallon gets replaced each time, so 1/2 gallon of 5.7 gets mixed into 3 gallons at 5.6. Then, its another several hours before the next 1/2 gallon of 5.7 gets mixed in.
I suspect it could take several days before the accumulator tank goes up from 5.6 to 5.7. By then, it will likely be time to re-fill the rez.
This is a whole different animal than what I have been dealing with. I suspect Im going to need to do larger changes at a time in the rez than 0.1 PH. If I raise the rez 0.1 PH per day, that means I go from 5.5 to 6.2 in seven days, but it might be another 3 or 4 days before the roots get up to 6.2. But the rez will be empty in about 5 days at current flow rates.
The new rez will start at 5.5 again, and lower the PH in the accumulator tank back down over several days. Its going to take some trial and error to find a good change rate to match the rate I empty the rez.
I havent done the math on @SuperiorBuds accumulator tank, and pressure differentials, but Im guessing he should have roughly double the re-fill volume I have when the pressure pump kicks in. So, his system should transfer any PH change to the roots faster than my system does. Plus, his higher over all flow rate (more nozzles and more plants) will also speed up how fast any PH changes get to the roots.
Thats a long lead up to say Im increasing the PH in the rez from 5.6 to 5.7. Im going to watch the nozzle PH every few hours to se ehow long it takes to show the change - assuming the system remains stable.
Well, I tried that initially. For me, there is no lower PH value that lets my plants absorb Mg well enough. Looking at the chart, anything under 5.8 is red so from the chart and confirmed by my experimental results, higher values are suggested so I put my PH right in the middle of the green bar at 6.1-6.2. I also doubled the amount of Mg in the dosing bucket that holds it so the ratio is double the suggested value.
I was reassured to do this by the MG thread where precipitation only happened at much higher PH values.
My only concern is limiting PK availability.
Regarding the slow change of your accumulator tank, is there no way to have a bypass valve that recirculates some of the nutes in the accumulator with the rez so your changes happen in less than a day rather than more than 5?
I filled and flushed the accumulator nearly 10 times last night while testing. Luckily for me there seems to be nothing left in there ā I was getting the same PH/EC out as I was feeding in. Whew!
I discovered that I didnāt have a bad solenoid like I thought ā my dumb ass didnāt look at the arrow last time apparently and had the tester installed backwards.
And I also rediscovered (the hard way) that water at 100 psi will launch an unsecured hose and spray the room like a 2 year old boy learning how to pee. I needed to wipe down the walls, but damnā¦
I am using a 2.2 gallon accumulator and 12 of the higher flow nozzles, Iāll see if I can get the math worked out today myself. I am hoping to refill the accumulator a lot more often, especially since any runoff is getting caught anyways. (Though as you found I want to ensure thereās plenty of dry time between the cycles still.) Ugh, I canāt wait to get back to testing.
We all make silly mistakes now and then. At this point I stopped blaming the weed and just started blaming my age.
Thatās a really interesting idea. @anon32470837 ā you already have a secondary set of timers, correct? (High and Low zones in the growbed I think?) It would be kinda interesting to see if you could have a solenoid that just dumps a bunch of the pressurized solution back to the res for a ācycleā.
Yeah, running at higher PH levels isnt the automatic death sentence some people would have you believe. I figure the roots in my system have spent more time above 6 than below since early in the grow - when the tank first got infected. The main issue I have seen is burning from over feeding, but there have also been some signs of Mg def - but not real bad. Purple stems mostly.
I can drain the accumulator tank bck into the rez manually, and have done it quite often. I have a T and a valve in the system between the pressure pump and the accumulator tank that I can use to drain the accumulator back into the rez. I have been doing that when ever I change the EC - especially lowering it - or when the PH has gotten way out of hand, etc. I also did it when adding chlorine or copper - to get the treated water into the entire system at the same strength.
The only down side to doing that is that my solenoid type pressure pump is noisy. Plus, when I drain the accumulator tank all the way down, it takes long enough to re-fill it that the pump gets kind of warm. Its still within spec as far as max temp, but it gets hot enough to make me want to be careful. So, when I do a 100% drain, I do the re-fill in two stages allowing the pump to cool in between. This is the main reason I want to change over to the diaphragm type pump when I can afford it.
In order to automate this you would need to start the drain cycle right before the pump turned on and run it long enough to drain a significant amount of the tank, but not long enough to drain it completely. I think that would require a second pressure sensor. I dont know how you would adjust a timer on the fly to run at the proper time. Well, I guess you could just run it long enough to do a partial drain.
Other wise, if the drain cycle happens when the pump is running, you would just be re-circulating water that was fresh from the rez rather than water from the tank. The accumulator tanks only have a single in/out tap, so you can only fill it OR drain it - not both at the same time.
Im thinking this issue can be handled three different ways.
it could be automated with another pressure sensor/arduino setup, but thats down the road. Its not going to be a simple programming thing either. There are different degrees of hysteresis in different parts of the system to deal with. The rez will react pretty fast, but the accumulator tank will be a good bit slower, and the nozzles slower yet.
In the mean time, I can just keep doing it manually as needed. Rather than dumping large portions of the tank back into the rez, I think I can come up with a schedule to raise the PH in the rez so that the PH at the nozzles climbs at a reasonable rate, but I will have to play with that some more.
As a data point - I raised the PH in the rez last night at around 9PM. Its now 8AM and the tank PH is flickering between 5.6 and 5.7, so its gone up just a bit in the last 12 hours. The PH at the nozzles is still a solid 5.6. The pressure pump ran one time between when I did the change and now - about 3 am. It ran again just after I took samples this morning.
Thats another detail to track. If I take samples right after the pump has run, there will be fresh water from the rez in the lines and in the tank that will read the same as the rez until it has time to equalize with the water thats already in there.
Thats good news! Did you use any chlorine or anything to kill the crap or just flush? I have no clue if your gunk is the same as mine, so you may not need to kill anything.
That gets pretty exciting doesnt it I launched a nozzle across the room one time and had a heck of a time finding it!.
Is that 2.2 gallons the nominal volume or the actual amount it can hold? Atomizer said that most tanks only hold about 3/4 of the nominal volume. My tank is listed at a 5 gallon, but the spec sheet show an āacceptance volumeā of 3.8 gallons. By my calcs its actually closer to 3.7 gallons of real usable volume.
If that 2.2 is nominal volume, then your tank probably actually holds closer to 2.2 x 0.75 = 1.65 gallons. If you are running 80 psi to 120 psi, then that works out to about .49 gallons per re-fill. Thats almost exactly what mine is at the moment. The big difference is yours will cycle much more often than mine does. Your PH changes should propagate through your system much faster than mine.
I added a section to the spread sheet that does the tank math. Insert your actual tank volume, cut in and cut off pressure settings. It will calculate the volume of air in the tank and how much volume you actually get out between those two pressures.
On second thought, I think you guys are right - I cant leave the PH to swing this slow. I only have 10-12 gallons of usable volume in my rez. At my current flow rate, that gets used up in about 5 or 6 days, so I cant wait 2 weeks for the PH changes to progress through the system. Im going to have to do at least partial drain and re-fills every day or so, or I will never get the PH at the roots up to the hi end of the swing.
Im now trying to decide how to handle this at the end of the swing when the rez is empty and the PH is up at 6+.
Im reluctant to just jump instantly from 6+ down to 5.5. Im worried about PH shock from too fast a change.
It looks like the alternative is to start the rez at 5.5ish, then run it up fast enough for the nozzles to see 6.2ish after three days, then start back down until the rez is empty again? That seems kind of fast to me - having the PH go from 5.5 to 6.2, then back to 5.5 over 5 or 6 days?
The alternative is to go from 5.5 to 6 over the full 6 days, then when I re-fill the rez, start it at the hi end, and PH it down over the next 6 days. Im not wild about forcing the PH that hi to start. That means adding PH up from the beginning, then PH down to lower it.
hmmmmm. This probably isnt really as big an issue as it seems. Lots of folks have been doing HPA with accumulator tanks and they dont seem to be concerned with PH swingsā¦
I didnt like this idea at first. I didnt want to risk running the tank too low, but thats not an issue as long as each ādumpā is relatively small.
This would be a simple way to increase the number of cycles and reduce the time between cycles. That will speed up the PH propagation through the system. I dont have a spare timer at the moment, but I need to order at least one for a backup, and they are cheap enough.
In the mean time, I think I will try opening my drain valve that feeds the tank back to the rez so it just barely drips. I will see if I can get it slow enough to maybe double the number of re-fill cycles in a day and see how that goes.
That means more wear and tear on the pumps, but I dont see any way around that.
The roots survived the recent ordeals of getting saturated, then having the water off for extended periods and finally getting a shor dose of super concentrated chlorine. I can see brown areas near the nozzles where the chlorine did some damage.
Over all, the quantity of fuzzies is down a lot. Root still look pretty good, but its mostly regular hydro roots rather than fuzzy hairs. In the out of the way sections, and large parts of the lower chamber, there are still lots of fuzzy hairs, but fewer than before. Hopefully, the better PH range now will reverse that trend
Today is day 48 of 12/12. The earliest this strain of C99 is supposed to be ready is 50 days. Im pretty sure its not going to be ready in two more days. The trics are almost all milky, but still only a few amber ones, and the pistils are still at least 50% white. Im thinking it needs at least another week.
So, Im NOT proving that HPA finishes faster than regular hydro. Maybe they meant it was faster if you DIDNT stress the crap out of the plants??
Turns out I was right about being wrong about the slow PH change progression through the system. Turns out, its not an issue, or at least its not the same issue I thought it was, because the system doesnt behave like I thought.
I was picturing the fresh 1/2 gallon of nutes that get added to the accumulator tank every time the pressure pump kicks on, as mixing rapidly with the 3 gallons already in the tank - or at least mixing fairly quickly with a resulting PH between the two starting PH levels.
But, it doesnt work that way. Its because the accumulator tank only has a single in/out port. The fresh batch of nutes does not flow through the tank, it just fills up the bottom. It looks like there isnt that much mixing going on either.
So far, every time I change the PH in the rez, that same PH shows up within just a few minutes at the nozzles - and then stays the same for hours before going down slightly. This is while Im bumping the PH up in the rez.
Here is a simplified drawing of the plumbing. You can see how the nutes will get pumped into the tank, but it fills and drains from the bottom. It also fills pretty slooooowly, so there is no vigorous mixing going on inside the tank. Once the fill cycle ends, the nutes that immediately start to feed the nozzles are the same nutes that just got pumped out of the rez - so the same PH as the rez.
This is good because I dont need to go to extra trouble to get the PH at the nozzles to change quickly enough, but it has me a little concerned about the āoldā nutes left in the rez aging over time. This is probably not a serious issue either - unless there is algae growing in the tank. Still, I find it disagreeable to have āold nutesā hanging around that dont get mixed in or cleaned out within a reasonable amount of time.
Easy fix is to just drain the tank back into the rez periodically or toss it every so often. Like I said, as long as the system stays clean, I doubt this will be any problem. Im sure there is some mixing going on just through Brownian motion, so I think Im just being paranoid here.
As far as staying clean - this zombie algae crap really is UN-dead zombie crap! I just discovered some new algae strands growing on the end of the UV light!! It was right on the cord attachment point, and that spot is more or less blocked from any direct UV light, but this is still very concerning. The sealant I put on the cord has pulled cracked where I bent the cord, so Im guessing some algae started growing in there and then didnt get the full chlorine treatment last time. I may go ahead an add the second UV light, but I am for sure sticking with chlorine treatments at 2 - 4 PPM minimum.
After this grow Im going to have to do a super super super sterilization and then probably stick with sterile rez procedure. I just hope I can keep the chlorine low enough to allow fuzzy hairs next time around.
So far, there is still no sign of PH drift in the tank or the rest of the system - which is kind of surprising given the algae on the light cord.
Itās Exodus Psychosis. I am finally learning what it really needs. Only had it for more than a decadeā¦
It is a cross of exodus cheese made by the same guy that made cheese.
It does everything I want a plant to do. Vigorous in every stage. Heavy yielder and also high quality. Strong. Continues to put out roots deep into flower so you can switch very early and still get a good result. Very mould resistant (I can run at 90RH% with no problems). Very good growers plant.
It is the only weed I know of that people say they get a āweed hangoverā from smoking.
