pH constantly rising?!? WTF? Advice needed, please!

[Boylobster]

Here's the score: I just put newly rooted clones into their DWC buckets with a mild, pH balanced fert solution. Within a day, the pH had wandered up from 5.7 to 6.8! Today, I dropped the pH back to down to ~5.6-5.7, and now, just hours later, it's back up to 6.1 in all three buckets. :worried

What could be causing this? I used 0ppm RO water cut with maybe a 1/4 volume of local spring water to make a solution that started fresh at maybe... 80ppm. The buckets are brand new, straight from the store. The airstones are brand new, high-quality ceramic diffusers. The nutes are Flora Nova Grow one-part solution...

Can anyone tell me which of these factors could be the culprit and why? This is very alarming, 'cause I obviously can't just keep dumping acid into the solution... they're only babies, for the love of god!!!!

 

[hererisssh]

Don't sweat it too much bl. PH swing is a good thing within a reasonable range. 6.8 is high but 5.5 to 6.5 and everything in between is fine. Are you using PH controlling solutions?

 

[cell]

If mine aren't fed a consistent 5.8 they start to bend funny.

I would consider the ingredients in your nutes, which can raise/low the ph of your medium. Local spring water? Tap? My tap is highly alkaline, which I will never use. Distilled for me.

 

[Boylobster]

*pant, pant* ....you seem to have my back quite a bit man, thank you. What's meant by a "pH controlling" solution? I use GH pHUp and pHDown to tune the pH, but that's all. Do you mean something like a long term buffering agent?

Cell, thanks for the addition - I think I mentioned my h20 mix in the first post, but I also tend to write too much... :itwasntme ...I can see how you'd miss it. 1/4 local spring water, 3/4 pure RO water. Starting ppm was about 80-100. I've used the spring water straight for DWC buckets before with some success, so I figured cutting it with RO water would surely increase the stability of the solution, if anything.

:headbang ....rrrrrr.... These aren't the kind of mysteries I like...

 

[leadplant]

"...Do you mean something like a long term buffering agent?..."

IMO, thats whats needed. Tap or well water can work well as a buff agent. Some use calmag for that too. I'll bet the tds of that local spring water is still pretty low so you are basically using pure water which is very reactive. Its probably OK for watering but when adding ferts, things will start swinging around. Maybe I'm missing something, but I'm shocked when I see ferts being used with pure water unless that fert mix was blended to be used that way. They usually arent.

 

[Boylobster]

Maybe I'm missing something, but I'm shocked when I see ferts being used with pure water unless that fert mix was blended to be used that way. They usually arent.

! Well, it's *supposed* to be suitable for hydro or soil, but it's an all-purpose nute, and certainly not specifically made for hydro.

The spring water 'round here unfortunately has an EC about ~.3, or 300ppm. Pretty high... so I diluted it as described, added the nutes, and then pH balanced the solution with GH pHDown.

Are you saying that the nutes may not be pH stable in solution??? W.... W.... WTF? :P

 

[Stackin Paper]

When i ran waterfarms and any hydro set up for that matter i always found the ph would rise for the 1st 3 days after res change anyway,

as you already stated the 1st time round it raised from 5.7-6.8,

then the next time it went from 5.7-6.1,

i bet after the 3rd time it will start staying where you want it to be at roughly,

You said you have the ph up and down also,
never use the ph up and down at the same time, it wont do your plants any good, if you go too low accidentally with the ph down then either make a fresh batch up or add water to raise the ph then re'adjust the nutes to right ppm or ec however you're working.
if i was you i would ditch the ph up tbh. I've never personally had the ph go down unless i make it go down, always rises and i grew in farms and nft for 4-5yrs.

I will also add that my tapwater ec is 0.4ec and ph 7.9, i only ever ran my nutes at 1.2ec, 1.4 maximum andf thats in full flower, you don't need a lot of nutes to grow in these sytems tbh, don't know if he has threads at any other sites but check out a grower called Heath Robinson, he is a hydro master.

Hope some of this can be of any help to you bro.

 

[Boylobster]

Already is, man. Many thanks - I loooooooooove information. Hey Stackin, don't suppose you know the mechanics (well, chemical mechanics... :itwasntme), of *why* combining pHUp and pHDown is such a bad idea? I've heard that before, and it's not at all that I question your advise - quite the opposite; I just like to know the particulars whenever I can.

Good gravy, this forum is great! Y'all are great! :clapping :heart Stackin, I'll see if the pH stabilizes over the next day or two. I have a feeling that you're dead on with that, and I'll report back with further developments.

 

[FastForward]

If it's still aggro, try replacing the airstone with a waterpump - to keep the water moving and aerated. You should see more stable pH....that's what I'm doing....(recirc pump in my dripper setup instead of airstone, pH is rock solid....spoke to a mate also in a shitty hw area....he does the same with his flood and drain, no pH probs).

 

[hererisssh]

Yes bl I meant PH down/up though I try to use as little as absolutely possible. SP's got your back there and is dishing good advice.

 

[Boylobster]

Pfew.... I think SP nailed it; pH in all three buckets seems to have done exactly what he predicted - rose just a *sliver* higher, and stopped at about 6.2. I knocked it back down again just a lil' bit, and I expect that that's probably where it'll stay until I change nutes again.

Good lookin' out, SP, FF, herer, everybody... I'll be putting up a grow log soon that'll feature the Canna Aqua line of nutes, and I'm really, really stoked to see how it performs.

Thanks again guys; I don't anticipate more of this particular problem, but you can bet I'll have another question soon... :D

 

[cemchris]

Ph swing is your plants adjusting the solution to fit there needs. If you have problems in the future Silica will help level it out some. Keeps mine rock solid for more then a week and maybe jump a point or two. Also Temp has a big part of your ph. Temp swings will cause it to jump around.

 

[udub]

Wash those hydroton rocks good, at least 3 times. The dust on them raises ph

 

[Boylobster]

Word... I'd wondered if something like that could be at play. For example, the airstones I used to use where plain aquarium grade, and would deteriorate pretty rapidly in nutrient solution. Where would that stone material go, I wondered, and what effect would it have on pH, if any?

Anyway, yeah, I'll be more vigilant about rinsing the hydroton in the future; if nothing else, having that dust in the bottom of the res just annoys me. :)

 

[samino]

Also Temp has a big part of your ph. Temp swings will cause it to jump around.

My thoughts exactly, when temps are high they tend to drink more water and less nutes. Causing PH to rise! If you haven't already, I would shoot for temps around 75 degree mark.

 

[samino]

A good solution would be, adding as rez and pump for the buckets. And create a recirculating system. That would really help stabilize PH, and you get a lot of other benefits in the process.

 

[Boylobster]

Well, this is an older problem by now, but temps in the veg chamber were both stable and reasonable - in the low 70s.

Switching to a proper hydro formula (i.e. Canna Flores) has worked wonders for pH stability, and the plants seem to be diggin' it. Thumbs up for Canna's hydro line! :yes

 

[Boylobster]

samino, I'm working on an extra-special res and pump system that I hope to debut here soon... if I don't go on vacation first, that is! :D

 

[astro]

When possible I control my ph with nutes and water. Need ph lower add nutes need ph higher add water. Try not to use ph up and down unless totally necessary.

 

[Boylobster]

Hm... sounds good, but none of the nutes I've ever used seems to bring the pH below 6.2, even at high concentrations. Any suggestions there?