pH Moderation

[Nate Storey]

It seems to me that pH moderation is constantly coming up as a  subject in just about every discussion.  Because it's such an important detail of all aquaponic systems, I thought that I'd start a discussion to let folks chime in on what has worked and what hasn't worked as far as controlling system pH.  I know that some of you will say that the subject has already been talked to death in other discussions, but I think that this will be a great resource for folks who don't have the time to wade through the other discussions to glean details.  So experienced aquapons (that means you- Aleece, Murray, Rupert, etc.), and anyone else with questions or advice:  let's make life easy for the newbies and share some pH knowledge.

[Lonny Harper]

This is a good thread.  I"m cycling my system right and experiencing the same issues Lori is having.  Nothing is registering.  I'm almost two weeks into it running.  Based on what I've read, I just purchased my Master tester.

 

[Patrick McKee]

I'll chime in... when the PH is not at the optimum for aquaponically grown plants the first problem we have is a lack of chlorophyll production, yellowing or chlorosis from a nutrient deficiency. One solution is to adjust the PH towards the plants. I adjust to about 6.8 to 7 a little more towards the fish. I supplement with an organic chelated foliage micro nutrient spray. The iron, manganese and other nutrients only go into the plants through the leaves not in the water column. The nutrients needed for plant growth and chlorophyll production may be there but are "locked" out because the ph is out of a range they can get into the plants through the roots. Chelated just means the nutrients can enter the plant through the leaves, this is good because once inside the plant they can do their job until they are used up and you can add more. I know we don't want to add anything to the system unless necessary. Fish alone do a pretty good job of providing nutrients to the plants but fish alone do not provide the exact levels of nutrients needed for optimum plant growth.

[TCLynx]

local water chemistry play a bit roll in what pH adjustment or supplementation might be required just as much as the fish feed used.

[Michael Brown]

very interesting discussion on ph here, i've read a couple of pages and noticed talk of using citric acid as a ph down.  fresh lemon juice, from a lemon... that wouldn't cause harm to the bacteria?  i'm just remembering reading in sylvia's book that citric acid should not be used due to a negative effect on the bacteria.  maybe i'm remembering incorrectly, any information on the citric acid would be greatly appreciated!

just to add to this... i have a 10 gallon "ornamental" system setup in my house.  my water source has been tap water since the start.  it has been a tough road since it's treated with chloramine and has a ph which tests off the charts of my test kit at 9+.  i started with five store bought molly fish, i've lost two in the process.  the system has been running for about four weeks and my ammonia/nitrites are 0, nitrates hovering around 30-40ppm.  my ph has been steady at 8, so my system has been doing a good job at bringing the tap water down from the 9+ whatever it may be.  the molly fish like the higher ph from what i've read and seem very happy.  so just a bit of background on what i'm dealing with.  would it be ok to add a bit of fresh lemon juice to a gallon of tap water in a bucket to drop the ph down slightly then add that into the system next time i do a water change?  also, i'm using a 10 gallon grow bed filled with hydroton.

[TCLynx]

Citric acid is antibacterial and not really recommended,

However some fresh lemon juice is not as strong and probably wouldn't hurt so much but I doubt it will be super effective for you and using acid to adjust your tap water or well water constantly long term is not the best option (it will simply be releasing more calcium into your water and will likely cause some issues with potassium lock out because of too much calcium.)

collecting rain water or perhaps using some RO filtered water would be a better choice.

[Michael Brown]

alrighty, thanks tcl.  the rain water route seems easy enough.  wish i had a system in place to do that already, guess that's my next project

TCLynx said:

Citric acid is antibacterial and not really recommended,

However some fresh lemon juice is not as strong and probably wouldn't hurt so much but I doubt it will be super effective for you and using acid to adjust your tap water or well water constantly long term is not the best option (it will simply be releasing more calcium into your water and will likely cause some issues with potassium lock out because of too much calcium.)

collecting rain water or perhaps using some RO filtered water would be a better choice.