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Hi All,

In another discussion, some of us are trying to determine the ranges of PH for best growth of different crop grown. This can become a general guide for maintaining specific PH levels to suit the crop you choose to grow.

So, what is your average system PH and what plant (plant doing the best) do you notice thriving at this PH level?

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Hi Nate,

Very interesting approach using RO. Whether the geography, all source water can be "virginized" and manipulating the PH  becomes more manageable. I've noticed some people besides TC, on this site using well water and experiencing problems with nutrient imbalance affecting their AP, I think many can benefit from utilizing RO to treat system water.I can also see the relationship here with commercial growing.

I think how you cycle a system and the amount of bacteria you create is important when running at consistently low PH's to effectively utilize nutrient uptake. Thanks for sharing.

Nate I really like the RO concept for me. My well is is 7.8 to 8 and when in full summer mode I am adding about a 150 gal a week in my 1000 gal system. This will always keep my ph higher than desired. In your experience how much does  the RO drop ph. Can you recommend a good RO for about 300 to 400 gals a week. This RO will have to handle about 2500 gal system when completed and be able to keep it in top off water.
Nate Storey said:

Hi Harold,

Yes.  While source water can deliver some nutrients to your system, relying on source water for nutrition is just not worth it.  All of the plant nutrients you need can be found in your system with proper feeding and pH management.  My pH is low primarily because my nitrifying bacteria are really happy and I have almost no carbonates in my system because I use RO water as source water.  Basically, getting the carbonates out allows me to tightly control pH instead of loosely managing it.  It makes for a much more stress free life.  :)

I know there are a wide variety of ways to get things to work.  I can definitely see how rain water and RO water could make "control" easier.  I will however, keep experimenting with ways to work with hard well water as well since it is a very common situation.

 

And I have an even more powerful test tool, a system full of shells which generally keeps the pH up around 7.4-7.6 even during the rainy season.  Despite the extreme over abundance of calcium carbonate, this system still grows lots of plants.  It has it's problems but it still works and I never have to worry about the pH taking an extreme plunge.

 

Anyway.  This is an extremely educational thread, I've learned several things already and I expect this will keep going for a while.

Hi All,

Some information on buffering with KOH. In my country its very expensive even though we are among the large world manufacturers of KOH or potassium hydroxide or the common name caustic potash. Here its available in 50 lbs bags but I'm now trying to source it in smaller quantities.

Hi David, I think that you would eliminate a lot of your headaches by using an RO filter.  Our RO water comes out around 7.3 or 7.2. . . Down from the high 7s.  However, the benefit of RO is not initially dropping pH, but removing carbonates, allowing the pH to drop without being buffered up.  So essentially the benefit is that the water becomes much more obedient to your management.  TC, you're right- these systems definitely work in your pH range- I ran a system between 7.5 and 8 for two years without RO. . . .it worked but serious nutrient management was difficult.  Now that I'm on RO, my nutrient management is so much easier, with really rapid responses to nutrient introduction, and I've never had my pH crash.  Anyway, it's an investment of a couple hundred bucks for something that made my life a lot simpler.  Dave, there are quite a few RO filters on the market for cheap.  I've heard AquaticLife makes a nice RO filter that could give you a couple hundred gallons per week for cheap.  So long as you avoid flooding/whole-system refills, small filters will work for topping everything off. . .

Harold, maybe you could go in with someone on a 50lb bag and then just split it up?

Thanks Nate I needed that advice.

Nate Storey said:

Hi David, I think that you would eliminate a lot of your headaches by using an RO filter.  Our RO water comes out around 7.3 or 7.2. . . Down from the high 7s.  However, the benefit of RO is not initially dropping pH, but removing carbonates, allowing the pH to drop without being buffered up.  So essentially the benefit is that the water becomes much more obedient to your management.  TC, you're right- these systems definitely work in your pH range- I ran a system between 7.5 and 8 for two years without RO. . . .it worked but serious nutrient management was difficult.  Now that I'm on RO, my nutrient management is so much easier, with really rapid responses to nutrient introduction, and I've never had my pH crash.  Anyway, it's an investment of a couple hundred bucks for something that made my life a lot simpler.  Dave, there are quite a few RO filters on the market for cheap.  I've heard AquaticLife makes a nice RO filter that could give you a couple hundred gallons per week for cheap.  So long as you avoid flooding/whole-system refills, small filters will work for topping everything off. . .

Harold, maybe you could go in with someone on a 50lb bag and then just split it up?

 

Nate said:  Harold, maybe you could go in with someone on a 50lb bag and then just split it up?

 

Harold says: Geeeeez! Think i left my brain at home! Thanks again Nate.

Harold- or you could get into the soap-making or biodiesel business on the side!  Just what you need, one more thing right. . . :)

 

Hi Nate,

I've done some research on these already, but AP over this time is forcing my thinking more along the lines of conservation and sustainability these days . We really need to take more care of what we have left, don't you think?

On the subject of RO and rain water, rain water and RO are almost the same(demineralized). I think the reason I moved away from rainwater was because of the low PH's that develop as a consequence of its use and the fear of bacteria crashes. Add to this the need for almost daily buffering to maintain a specific PH suited to my target crop. The higher level of buffering with lime because of this began showing potassium deficiencies(previously discussed). So this is the reason I abandoned the idea altogether. With the information you gave us in this discussion I can see now how to manage this type of situation.(Thank You)

While I note your point of RO giving more control with PH and nutrient supplementation and before we all begin rushing out to RO setups, this may not be ideal for the average backyarder who is basically looking for a plant it and forget about it type of AP. The almost daily PH adjustment necessary with demineralized water may be too time consuming for some.

Right now I'm trying, through the higher ups, to bring AP to my country as a necessary alternative for future agriculture(long process here) and I see that RO and rainwater will have a large role to play in this when it happens. RO and Rain water will be great for those who want to target specific PH's and nutrient more suitable to efficient growing of their choice of crop (especially mono culture or in a commercial setting)


Nate Storey said:

Harold- or you could get into the soap-making or biodiesel business on the side!  Just what you need, one more thing right. . .

 

"this may not be ideal for the average backyarder who is basically looking for a plant it and forget about it type of AP." How true...I didn't really care to re-take Chem 101 when I got into this. However, I find this discussion rather fascinating in a couple of ways. Out here in the wilds of north county San Diego we struggle with high Ph water that is just slightly less hard than the average brick. I have not done any manipulation of the ratios except to add water to my system and I am having great luck with my squashes and pickling cucumbers as well as lettuce. On the other hand the watermelon and pumpkin are struggling...(lots of flowers, little growth, no fruit set). I suspect this may have more to do with tempature and placement than water nutrient quality, however, I am the newbie. Thank you Harold for the tip on the Vitamin C. I think I will have to look at a small RO system or at least hit the local supplier (25 cents a gallon, what a deal!) for replenishment. I like what Nate said about this being a simpler way to deal with nutrient manipulation; it just makes sense. You start with a blank slate and write your own strory. (so to speak). Take care...



Harold Sukhbir said:

Hi Nate,

I've done some research on these already, but AP over this time is forcing my thinking more along the lines of conservation and sustainability these days . We really need to take more care of what we have left, don't you think?

On the subject of RO and rain water, rain water and RO are almost the same(demineralized). I think the reason I moved away from rainwater was because of the low PH's that develop as a consequence of its use and the fear of bacteria crashes. Add to this the need for almost daily buffering to maintain a specific PH suited to my target crop. The higher level of buffering with lime because of this began showing potassium deficiencies(previously discussed). So this is the reason I abandoned the idea altogether. With the information you gave us in this discussion I can see now how to manage this type of situation.(Thank You)

While I note your point of RO giving more control with PH and nutrient supplementation and before we all begin rushing out to RO setups, this may not be ideal for the average backyarder who is basically looking for a plant it and forget about it type of AP. The almost daily PH adjustment necessary with demineralized water may be too time consuming for some.

Right now I'm trying, through the higher ups, to bring AP to my country as a necessary alternative for future agriculture(long process here) and I see that RO and rainwater will have a large role to play in this when it happens. RO and Rain water will be great for those who want to target specific PH's and nutrient more suitable to efficient growing of their choice of crop (especially mono culture or in a commercial setting)


Nate Storey said:

Harold- or you could get into the soap-making or biodiesel business on the side!  Just what you need, one more thing right. . .

 

Hi Paul,

FYI this is what happens with citric acid in AP

http://aquaponicscommunity.com/forum/topics/rookie-mistakes-you-sho...

You guys are totally right.  If you have access to rainwater- that's a fine way to go.  Here in the high desert though. . . that's not really possible.  You gotta use what you got!

 

Good luck with the watermelons Paul.  I've been making myself sick on them lately. . . they can be pretty finnicky.

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