best ways to keep res. ph down?

[jacobgriis02]

i know there will be a lot of good opinions here, in terms of different acids to use, so i welcome all of it. I have tap water ph of 8.3'ish , tested by both a droplet kit, and a new meter, I am having trouble keeping ph of 5.8 in my reservoir even though I am dripping to waste, so no worries with recirculated nutes YET. bc i planned to recirc. in the future but we will see.

I have 2 setips side by side, one with maxibloom 5-15-14 only, one using heads modified lucas formula 6-9. I am using general hydroponics ph down powder, at the moment, and like I was getting at, am not happy with my res. getting back to a ph of 8 after ~ 3-4 days, is that asking too much? Are there longer lasting ph down products I could get?

Thanks people.

 

[Snow Crash]

I've found TechnaFlora Nitric Acid based solution to be a little more stable. I also found I used less.

The stuff is touchy. Go light with it when you get close to your target pH, drop by drop for sure.

Recently I've been experimenting with Fulvic Acid as a pH down. Even with the nutritional benefits aside this has proven to be a better choice. It has held a completely static pH for me for 48 hours before. I don't usually keep a reservoir much longer than that, but I mean the pH didn't budge. Blew my mind.

I have been using Humboldt Nutrients FlavorFul and I find I use about as much volume of the Fulvic as I would when using GH Phosphoric Acid based liquid pH down. Except, with the Fulvic I don't have to come back and balance the rez every 12 hours.

The only other thing I can think of is to remove any air stone you have. I didn't find any difference in the final solution, coco doesn't need it, and if you'd like to keep the solution "moving" then you can try a submersible water pump instead ($15 at petco).

 

[jacobgriis02]

OOOh yea, good reply and thanks for the quickness too man, you are awesome. I forgot to mention I wasn't running an air pump in the res, but I was too high to remember I meant to mention that! (Bc i bought one to use and just haven't hooked it up yet bc of the fear of it messing with my already unstable ph) So you would recommend just ignoring the air pump for a coco res? Did I understand that right? Maybe as long as I can pull off a stable ph first?

So I have no qualms about buying some nitric acid, and fulvic acid, and using both if they heelp me acquire a more stable res. ph? I guess I should cut the nitric acid later in flower bc of added nitrogen? or not enough to matter?

 

[jacobgriis02]

PS. Assuming I acquire more stable res. ph, Would it be beneficial at all even run the AIR pump only for say the 20 minutes leading up to, and before the water pump came on, for my one time per day? To maybe get that dissolved oxygen up right before its fed to plants? And then have air pump turn off right after the water pump does, so it affects the res. ph as little as possible?

 

[Snow Crash]

PS. Assuming I acquire more stable res. ph, Would it be beneficial at all even run the AIR pump only for say the 20 minutes leading up to, and before the water pump came on, for my one time per day? To maybe get that dissolved oxygen up right before its fed to plants? And then have air pump turn off right after the water pump does, so it affects the res. ph as little as possible?

From what I've read, using an air stone does more harm to the elements in solution than it does in benefit aerating the solution. Canna actually recommends not using an air stone in "standing" hydroponic reservoirs with their own nutrients. I'm no scientist but I've tried both and the biggest difference I see is less funk and crud floating in the reservoir.

With the fulvic acid, I guess it'd be okay to aerate directly after balancing, or say, for 20 minutes prior to feeding, but you probably don't want to run it all the time. I don't even bother anymore with all that. Just the act of scooping up the water, pouring it out, having it splash all over the coco, all that seems to do all the extra aeration that the media needs. There's also a kind of "suction" action going on when the runoff drains out that helps keep at least the upper part of the media very aerated. I just don't see the need for an air stone with reservoirs and this media unless they are organic and rely on the air for microbial action in the rez (which is going to miff the pH no matter what you do).

Something else I can mention is that I actually use a combination of Potassium Silicate (DynaGro Pro-tekt) as a pH up and the Fulvic as a pH down. The Protekt I can run up to 4ml per gallon, so I start with 3ml while adding the rest of the nutrients. Then I start adding the Fulvic acid to bring the pH down once it is all mixed. I can use up to 5ml of the concentration I have, but usually don't need more than 2-3 of that to offset the Pro-Tekt. The two seem to work in combination keeping the pH from getting more acidic, or more alkaline.

But like I said, I ain't no skyintest.

 

[jacobgriis02]

Hmmm rerry intrerestring. What ph are you starting off with where you can add ph up first? For me, starting at 8.3 or so, I would want to say ef that. Even tho I bet the added silica would be good, shew, i been wanting to add some of my fine powdered diatomacious earth to my coco to see if it added a silica source, but then again, i would have no way to compare results one way or another. with my already maxibloom vs lucas 6-9 going on.

 

[iscrog4food]

I think the whole airstone thing depends if you are running a live res or a sterile res. If you are running a live rez (with beneficial bacteria) Then I believe you need an airstone. If you are seeing your ph walk and dont wanna use an airstone try adding H2O2 to the res to keep it sterile. I am not 100% but my understanding is that with live bacteria and sources of carbon the bacteria will result in an anerobic state which means bad bacteria grow and take all the dissolved O2 from the water (not good). Again I am no expert maby someone else can clear this up?

 

[Snow Crash]

Hmmm rerry intrerestring. What ph are you starting off with where you can add ph up first? For me, starting at 8.3 or so, I would want to say ef that. Even tho I bet the added silica would be good, shew, i been wanting to add some of my fine powdered diatomacious earth to my coco to see if it added a silica source, but then again, i would have no way to compare results one way or another. with my already maxibloom vs lucas 6-9 going on.

My water starts off around 7.4pH. Then I add all my nutrients, and the Potassium silicate, and that takes me to around 6.5pH or so. Then I add the Fulvic Acid, maybe 3ml, to bring it down under 6.0pH. With coco, I'm just not as neurotic about pH as I have in the past. Between 5.8 and 6.0 is perfectly fine.

During flowering I actually prefer to bring the pH up a little bit to help make Phosphorus more available and nitrogen less available.