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pH and water quality

Posted by chadg (My Page) on
Mon, Mar 3, 08 at 9:17


I got my floating raft system setup in the basement this weekend. I also have the lettuce seeds started and hope to transplat them into the hydroponics system soon.

My pH is high. Like 7.8pH and 250ppm at 59 degrees. I used our tap water and i know it is pretty hard.

I got some pH down from the aquarium store (was easier then driving an hour to the nearest hydroponic store) and added some of that (said two drops per gallon). It seems to bring the pH down to 7.5 last night, but when i checked it again this morning it was back up to 7.8.

Do i go buy bottled water and not use our tap water?
Do i need to get better pH down solution?

Follow-Up Postings:

RE: pH and water quality

I would definitely let the tap water sit out for at least one if not two nights. I also aerate the water with a air pump/stone while it sits out. While there may be similar or better products, I use Ionic Grow Hardwater as it seems to keep the PH stable. By the way, my tap water is around 300 ppm 7.8 PH. I do use half reverse osmosis and half tap water. Using the Ionic nutrient, I don't have to add any PH down.

RE: pH and water quality

Thanks for the infromation!

I read up on the Ionic Grow Hardwater and it appears to be a really good product. I will pick some up and give it a shot.

RE: pH and water quality

You can use ordinary white spirit vinegar to lower the pH. Use a 5cc syringe to dose at 1cc/g for a full point down. This may vary depending on the composition of the water. So try it out first.

RE: pH and water quality

Vinegar, lime juice and etc do not control Ph well in nutrient solutions.

RE: pH and water quality

willard3 / anyone,

Do you know how PH is controlled in an "organic" system? Is it just a matter of keeping up with it more often by using citric acid or something, or how is this done? I'd love to compare and see how this is done without a chemical in hydroponics.

I know that Earth Juice has a PH adjuster but I haven't used it and the guy at the hydro shop said you'd need to use a lot of it - I don't know, I have no experience with this but would like to know for the future.

Also I am currently using phosphoric acid and it seems like I have to add more than the bottle says per each point drop - I don't know still trying to figure it out.

Here are some links about the Earth Juice products:

The PH adjuster (Natural Up and Down):



RE: pH and water quality

The Earthjuice pH adjuster is probably an organic acid (such as: vinegar, citric acid or tannic acid). Tannic acid is sometimes obtained from oakleaf extracts.

Phosphoric acid is excellent as a hydro pH adjuster, but in my country it is difficult to obtain in smaller quantities, hence I use bicarb and vinegar as up- and down-adjusters. Been doing this for 6 years now.

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