high pH

[Dale]

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

[Ron]

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

[coldandwet]

why not use vinegar to lower ph?

[GpsFrontier]

Originally Posted by coldandwet

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.

[Luches]

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.

[coldandwet]

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.

[Luches]

Originally Posted by coldandwet

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!

[GpsFrontier]

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

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).