high pH
 

my hydrponics farm is using about 20 gallons of water a day with the local supply averaging a ph. of 8.2! correcting this supply
down to under 6.0 is geting rather expensive! What do you know is the least expensive safe acid for this purpose? Thank you
for the web site and keep up the good work! Sincerely Dale

Sorry Dale
I pay about $30. a gallon for pH down. No cheep and safe way to get around it.
I am lucky that my well water isn't as high as city water.
Ron

ph
 

why not use vinegar to lower ph?

Well the simple answer is it's not stable enough. If you don't mind adding it every day. As far as I can tell it is OK in a pinch, but wont hold very long. Also it can also change the nutrient composition every time you add a additive. So the less you the add the better. There are thousands of types of "acids" and or "bases"there not all the same. The price difference is just not worth the headaches as far as I can see. In fact its much more expensive from my experience.

Citric acid (synthetic and in fine granular form, but not necessarily food grade) is both, well suited and cheap.

Other less expensive alternatives are acids in high concentrations (but they need to be handled with ABSOLUTE CARE and best knowledge of possible hazards): Nitric Acid, here the Nitrogen content has to be considered. Phosphoric acid, here the Phosphor content has even to be more carefully considered, as it may affect calcium uptake. Potassium phosphate Mono, is less potent, but not hazardous (needs to be handled with appropriate care though),but it adds notable amounts of both, P and K to the nutrients.

thanks for the input on geting ph down. my resivior is also near 8. my 70 gal.system is flood and drain type. I have it cyceling once every 3 hr. 24 /7.as Iwait for my seedlings. when I go to add fertilizer @ 1/2 strengh won,t the ph automaticaly drop a point or so? my nuit. are also heated to73 de f. and airated. any reply on subject greatly apprecieated.

The key to adequate PH is water with low mineral content, as hard water has a lot of basic (and neutral) components. Actually mostly calcium that is responsible for- and buffers high PH. In such case, week acids will be dissolved over night by the basic minerals and you need to repeat the procedure. Best is always to use neutral PH base water (7.x), or mix 50/50, RO, rain, or distilled water. It may solve all of your PH problems.

And yes nutrients are mostly calculated to lower and buffer PH down to nearly adequate (around 6). But this will (obviously) not be be the case with lower or half concentration. It's actually a general problem with growing seedlings or running low nutrient strategies with some plants. Then again, you may successfully grow seedlings in somewhat higher PH. Well, you can always try it with 2 different groups of seedlings, corrected PH (acid) and a bit too high PH.

You may indeed increase nutrient strength somewhat (for seedlings and maturing plants) to lower PH and getting a better buffer with ideal PH, but don't do it unless you have an EC-meter and actually know what you are doing!

I've thought about using this also, I don't know how well it would work. But it's not cheep for me, I get it at the grocery store in the spice isle (called, Sour Salt, it's 100% citrus acid) and runs about $2, but it's only 1/2 ounce. I use Earth juice Dry pH adjusting crystals, I got both my pH up and down (1 pound ea) for under $20. That's 32 times as much (32x 1/2 ounce=1 pound) for less than $10. It has lasted me almost a year, I still have some of each (up/down) left. I cant see anything else being much cheaper. The trick is learning how much to use, but you have that problem with any pH product (made for hydro or not).

I pay 2.50 $ (two) USD per kilo (around 2 pounds) for citric acid at my chemistry supply store, and obviously consider this as cheap.

5% citric acid is supposed to have a pH between 1.80 and 2.00

Dosing example for Citric Acid: 1 Gram of 100% pure citric acid powder per 100 Liter of nutrient solution = 1% would bring down the PH way under 6 (depending on acidity of the solution).

Hence 0.5-0.75 gr per 100 Liter of nutrient solution is a good starting point to bring down the PH to somewhat under 6. You may simply dissolve 5-7.5 gram in 1 Liter and use 100ml (equals 1/10 of 10 time smore) per 100 Liter. Respectively dissolve 10-15 gram in 2 Liter and use 100ml/100L as well.

PS: I am used to metric weights and volumes, which are actually much easier to calculate, as volume/weight has the same relation (1gr of water = 1 milliliter) hence 10 gr dissolved in 1 Liter equals 1%!

Disclaimer: Use at your own risk ;)

I would consider that inexpensive also, provided I could get the same price.
Considering that $10 lasts me over a year, I'm not really concerned with the price of using the right stuff. I also wouldn't recommend using something not designed for hydroponics either.

The disclaimer is about the dosage I recommend only.

Although citric acid isn't actually designed for hydroponics, it can be considered as 100% suited. It is among others even recommended as a fine acid buffer by a chemist who is actually working as a nutrient designer for a nutrient manufacturer.

Sorry I misread your disclaimer. Because I mentioned before that you will have the problem of dosage with any pH product (made for hydro or not), that didn't seem to be an issue to me. I know that citric acid is used in manufacturing hydroponic pH adjusters, It may in fact be the base ingredient with what I use (so it's has been guessed). But never the less. For anyone starting out in hydroponics, I cant recommend using a product that wasn't designed for hydroponics, at least until they have gained some experience and are willing to sacrifice the plants to experiment.

Citric acid is as good and as suited as any expensive product specially designed for the purpose. It's even less harmful for both, the user and the plants- than most acid based commercial products and therefor it can be used as such by anyone. Hence I don't see any objective foundation to not recommend it, or restrict it's use.

Furthermore I believe that anyone interested can truly take it from here by themselves :D

That's fine, I know that citric acid can be used by anyone, and I'm not restricting it's use, I don't have the authority to restrict it even if I wanted to. I am simply saying that as long as you are willing to sacrifice plants to experiments, feel free to use anything you wish. Hopefully they will post the results.

My quote is quite good, except for some people who actually didn't try anything I recommend, - but tried to discredit me instead with no reason or reasons unknown to me. :)

I can say exactly the same thing (if I wanted too).