I have humic acid in powder but it’s hydrophobic, and just floats around on the surface of the water.
The vinegar will keep the ph down for about 18 hours then it starts to climb again, and after a couple of days is back up around 7.5 to 8.
There is nowhere I know that sells sulphuric acid around here, I wish they did, I have several batteries I could bring back to life.
Yes, Humic acid is generally insoluble at any PH, however there is a nifty product called Black Earth DS-80 (DS stands for Dry Soluble) which is a soluble form of humic and fulvic acid, as well as added nutrients N and K. It is made by a company called Black Earth Humic, and is generally sold to large-scale farmers only, however you can find stores here and there that do carry it. There is also a product on Amazon called “Wow Soluble DS-80 Humic and Fulvic Acid Organic Fertilizer”, but I have never tried it, but it looks like it might be good and very similar.
Thanks for the info I will look into that, Cheers.
Fulvex is a humic/fulvic acid solution. I have used it along with cider vinegar to lower pH. I am guessing that the issue is pH drift in a reservoir?
yes, in a res or in a cloner the ph can drift dramatically depending on the buffering agent you use. Fulvex and apple cider vinegar do work, however the sulfuric acid is much cheaper and more stable so it’s less work and less cost to maintain. Also, as mentioned, the sulfuric acid provides added goodness that other fertilizer or watering programs don’t, and the apple cider vinegar doesn’t really add any trace elements that are needed by the plants, as far as I am aware. But, to each their own - whatever works for you is great.
well…in soil drift is not an issue. In containers it is a good idea to pH. Sulfuric acid is much more caustic than household vinegar. And it were cheap I’d likely go white vinegar. Then some make an organic supplement with crushed eggshells and brown rice vinegar.
But as you say-
Growing media pH can also drift up or down depending on the balance of many different things such as acidification of the medium by the plant roots, lime activity and use of an acid or basic reaction fertilizer. Contrary to popular belief, the PH of the water does not influence the pH of the growing medium - it is the bicarbonate and carbonate levels in the water (known collectively as alkalinity) as well as the buffer you use to correct it, the potential acidity or basicity of the fertilizer and the plant itself.
Look for battery electrolyte solution. That’s what it’s sold as in parts stores. If you have an advanced auto parts or autozone near by they should have it
Cheers for the tip
as @Daytripr69 said, and as mentioned in the first post, ask them at your local auto store, it isn’t something they usually have on the shelf. Ask for “battery acid”
The reason I said electrolyte solution is because when I asked for battery acid the morons at my local store looked at me like I had three heads lol I asked for battery electrolyte solution and he had an idea what I was talking about and found it in the computer. Got to remember the people behind the counter need year make and model for a distributor hold down on a small block chevrolet when the same piece fits every chevrolet engine with a distributor lol
In this recipe we are diluting the sulfuric acid to approx 1.65% so it isn’t really that caustic at all. I put the warnings on the recipe because people can be stupid. Also, don’t be careless with vinegar, it can be corrosive and may cause damage with prolonged contact as well.
If you’re getting it from the auto parts store then it’s already diluted enough that anything less than prolonged contact (10 min or more) only leads to minor skin irritations in most. I myself don’t when notice because of the calluses on my hands. Once diluted further it might cause irritation if you soak in it for an hour. If you’re worried about pumps and the like the nutrient solution isn’t going to be any more caustic than it already is
I’m using 96% sulphuric acid drain cleaner. The only thing I wished I had done earlier is to put it in a glass container instead of keeping it in the plastic bottle. After a few years it starts to gradually perspire through the plastic and now I have a ring etched in the shelf where the bottle used to be.
gobbledegook
If I failed to explain myself to be understood properly, I apologize. If that is the case let me know and I will be happy to try to break it down more clearly. I will also provide links supporting the information provided if you wish. If you have other thoughts, let’s hear your take on it, along with the science to back it up - I am always open to new ideas.
These threads are great, it’s like peeking behind the veil of all the fancy nutes we pay so much for. Thanks for doing them.
Is there something readily available that can be used for pure phosphorous?
thanks much, I am glad you are enjoying the DIY threads, and I hope that they help save you some money so you have more to spend on seeds 
As far as phosphorous, fertilizer/soil pH controls much of the phosphorus availability to plants, so the best way to keep phosphorous available to your plant is to closely monitor the PH.
The Hammerhead and MOAB are both PK boosters you can make yourself for pennies.
Interesting, thanks. The problem is I use mega crop which is already super high in K so when I add a PK booster I end up with way too much potassium and still not as much phosphorous as I’d like. I tried ‘treble super phosphate’, but it’s more of a lawn care type product and didn’t work for me. It seems hard to find just P without a bunch of K or N tagging along.
Colloidal Phosphate aka Soft Rock Phosphate is a great source of phosphorous for your plants, since they can only take up inorganic phosphates. Down To Earth has a 0-3-0 Rock phosphate.
https://downtoearthfertilizer.com/products/single-ingredients/rock-phosphate/