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PH down liquid or powder


I had bought a liquid PH kit that came with 2 small bottles of DOWN and UP. I literally used almost 70% of the PH DOWN just to get two 5 gallon reservoirs (buckets) to 5.8-6.0 PH which I had only put roughly 3 gallons of 7.6 PH water in each reservoir.

For 1 gallon of the liquid PH DOWN is $36 and I still don't think it would be quite enough and seems a bit expensive. However I come across 1 LB of NATURAL ph DOWN POWDER HYDROPONIC CITRIC ACID for only $10. Would I get more for my money out of the 1LB of powder or is there benefits to using the liquid version? Any insight would be greatly appreciated.


Member of the Month: Mar 2016 - Plant of the Month: Nov 2015
I second the new pH pen. I use about 1 ml per gallon to bring my tap water down around 6.0

Edit: Spend the extra dollars and get a quality pen like BlueLab or comparable. If you're going to check and chase pH you might as well make it as easy and accurate as possible.


My water starts out at 8.0 which seems kind of high possibly making me need twice as much. Went to lowes, walmart, and tractor supply yesterday in search for some PH down neither had any what so ever. Come home to order some online afterwards and after some more reading and googling before purchase I had come across someone mentioning sulfuric acid as a subsitute. Did more research on sulfuric acid and it seems like it's BETTER & cheaper then phosphoric acid. Supposedly for $7 (any auto parts store sells 33% sulfuric acid) you can make 4-5 gallons of PH down, 1 gallon of GH's PH down is $37 so it is significantly cheaper and suppose to actually be better then what GH (general hydroponics) uses (phosphoric acid).

Im going to try it out today if I can get my hands on it, theres not many lawn & garden shops near me but theres plenty of auto shops haha! Really can't believe it's the pen as it reads RO water at 7.0, isn't it just reading salts in the water which is a basic process? I believe it's this cheap PH down that is the culprit it's not even GR it is Atlas Scientific (off ebay) probably watered down to hell. In order to bring it from 6.2-5.8 I have to put 1-2 TSP just for 3 gallons of water.


Well-Known Member
That may be a kit used for spas or pools and does not play well with hydro. Get some liquid PH down from a hydro store and you'll be golden.
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