PH keeps rising

[Lathund]

Hi.

What acid do you use?

If you use little or no nutrients, nitrogen based pH-down may effect your NO3-NH4 relationship. That will again effect your pH.
In your case i suspect to little NH4 in your solution compared to NO3.

Found this information on the topic.

Read this: https://www.cannagardening.com/how_ammonium_nitrate_ratio_affects_your_plants

Note: If you grow cold, pay attention to this:
"At lower temperatures, ammonium nutrition may be a more appropriate choice, because oxygen and sugars are more available at root level. Additionally, since the transport of nitrate to the leaves is restricted at low temperatures, fertilization based on nitrates will only delay the growth of the plant. The effect of the substrate temperature also depends on plant species."

And:
The effect of ammonium and nitrate uptake is especially important in soil-less media, where the roots can affect the pH of the medium more quickly because their volume is relatively large compared with the volume of the medium. To prevent the pH of the medium from changing too rapidly, an appropriate ammonium/nitrate ratio and substrate temperature are essential, according to the plants growth stage.

Hi!

Acid as in PH regulating acid? I use Biobizz PH down. I've tried finding if it's nitrogen based but the only thing I've found so far is that it contains lemon acid.

Thanks for the link, I've read through but can't say I actually understand all of it. What would my best course of action be at this stage?

I realise I'm asking a lot, hope you guys have the time to help a newb out.

 

[Lathund]

I found the ingredients to MaxiBloom here:

https://www.hydroexperts.com.au/General-Hydroponics-MaxiBloom-1KG-Powder-Nutrient-Food-for-Flowers

Does it help knowing the ammonia and nitrate ratios?

 

[superpedro]

Hi.

No, my guess was based on you using a nitric acid not citric. If nitric acid is used with low amounts of nutients in hard water, it can cause the pH to become unstable because of the NO3/NH4 relationship.
Do you know how cold you water gets with the light off?

 

[SuperBadGrower]

Citric is very unstable, weak acid. Phosphoric or sulfuric will perform much better.

 

[Douglas.Curtis]

When I did go with just warm water I felt that the nutrient didn't dissolve well enough, leaving a powdery residue on the bottom. Might not be a problem though and will possibly dissolve over a longer period of time?

Yes, it will dissolve over a short period of time unless it's a 'precipitate' from a combination of something in your tap water and the Maxibloom.

The hydro reservoir holds around 70L of water. I mixed 20g of nutrients in to around 1-1.5L of water before I poured it in to the reservoir. Is this a large enough solution?

And to be extremely clear, I need to purge the entire reservoir before starting over I guess?

Thanks again!

Without knowing what's really going on, purging the entire reservoir is definitely recommended.

That should be enough water for 20 grams as long as the wait time is short. 20 grams in 1 liter will drop the pH very low, and over time this can cause elements to combine and balances to be upset. 45 liters of solution is about right for 400w of HID lighting with DWC, and a flood table works well with even less. How many watts are you running and what size flowering area?

BTW: Maxibloom is usually around $15... that link is a ridiculous price, especially if they hit you with shipping charges as well.

 

[Lathund]

Hi.

No, my guess was based on you using a nitric acid not citric. If nitric acid is used with low amounts of nutients in hard water, it can cause the pH to become unstable because of the NO3/NH4 relationship.
Do you know how cold you water gets with the light off?

Citric is very unstable, weak acid. Phosphoric or sulfuric will perform much better.

I don't know exactly how cold, but too cold. Below 10C. I do realise that this is far from optimal, the grow area went colder than I thought it would. Right now it's not really about growing, it's about maintaining the plants until the warmer months come.

Yes, it will dissolve over a short period of time unless it's a 'precipitate' from a combination of something in your tap water and the Maxibloom.


Without knowing what's really going on, purging the entire reservoir is definitely recommended.

That should be enough water for 20 grams as long as the wait time is short. 20 grams in 1 liter will drop the pH very low, and over time this can cause elements to combine and balances to be upset. 45 liters of solution is about right for 400w of HID lighting with DWC, and a flood table works well with even less. How many watts are you running and what size flowering area?

BTW: Maxibloom is usually around $15... that link is a ridiculous price, especially if they hit you with shipping charges as well.

I'm thinking I'll switch out the powder nutes to GHE liquid nutes, Flora Micro and Flora Bloom, as the Lucas formula was originally intended. And get GHE PH down as well, wich is based on phosphoric acid, those two should work well together and that would hopefully eliminate the reservoir issues. What do you guys think?

--------------------

Before you tell me that the grow area isn't working, I know it isn't. I didn't expect it to be as cold at it is, ironically when the warmer months come I'll battle the heat instead. Right now I'm not trying to grow, I'm just trying to maintain until warmer months.

Next winter I'll tear everything down and rebuild the entire grow area. Insulation, temperature control, the works. But I'll have to make due for now.

Thanks again!

 

[SuperBadGrower]

Honestly, what I would do is buy the 3 types of PH down and and see what works for you. Nitric, sulfuric, phosphoric are common ones in bottles. If one works much better than the others, great. The worst that can happen is that you will have 3 bottles of ph down which probably work a bit better better than the citric.
Phosphoric acid is the most common one and countless people use it full cycle. To really understand what these things do you need to be a chemist. you can spend hours browsing about it on the internet and still be none the wiser. Better to let it go a bit

 

[Douglas.Curtis]

I suggest an aquarium heater set at 20C to maintain water temps. Colder than 18C and you'll have nutrient uptake issues.

The next bit of kit you'll want is an r/o unit, so you can quit bonking around with your tap water chemistry. pH is rock solid predictable when you use clean water. You'll also need pH up because you won't be fighting the mystery elements in it and nutes drop pH like a rock in a pond.

 

[Lathund]

Honestly, what I would do is buy the 3 types of PH down and and see what works for you. Nitric, sulfuric, phosphoric are common ones in bottles. If one works much better than the others, great. The worst that can happen is that you will have 3 bottles of ph down which probably work a bit better better than the citric.
Phosphoric acid is the most common one and countless people use it full cycle. To really understand what these things do you need to be a chemist. you can spend hours browsing about it on the internet and still be none the wiser. Better to let it go a bit

I went out and got the nutes today, along with GHE PH down. Hopefully this will work. I definitley hear you, you can dive head first in to it all but when it's all said and done I'm definitley not skilled enough to actually understand it all and take it all in to practice. And honestly, not that interested in all of the micro details.

I kind of landed on common sense, nutes and ph buffers of the same brand should be designed to work together. I guess I'll find out soon enough!

I suggest an aquarium heater set at 20C to maintain water temps. Colder than 18C and you'll have nutrient uptake issues.

The next bit of kit you'll want is an r/o unit, so you can quit bonking around with your tap water chemistry. pH is rock solid predictable when you use clean water. You'll also need pH up because you won't be fighting the mystery elements in it and nutes drop pH like a rock in a pond.

Thanks for the suggestion! At the moment I don't plan to add anything more gear wise, quite simply the budget doesn't allow it. I'm a multi diagnose patient (the reason for me to grow in the first place) and I don't exactly roll around in money due to my situation haha!

I definitley want to get a r/o unit down the road, probably when I do the major rebuild. I'm already sketching it all up in my head, big plans, will definitley ask for advice her before I go ahead with any of it though! I need to keep it pretty stealth though, so that's a big consideration for me to keep in mind.

I appreciate all of the help here, it's worth so much to me! I'll let you know how it goes after I've purged the reservoir and got it up and running again.

Thanks again!

 

[Douglas.Curtis]

Awesome and you're welcome.

I hear you on funding, it's been a constant nightmare here as well. If I didn't follow legislation I'd be selling cannabis at $65/8th and wouldn't have any budget issues. As it is I struggle with moronic plant limits, unaffordable permit and taxing structures and many other stupidities of legislature. Wheeee!