Aquaponic Gardening

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Hello,

I have a question. My system consists of a 300 Gallon fish tank, 150 Gallon sump tank, 2- 3x6x1 ft grow beds filled with "Plant It" clay balls. No plants yet.

I am in the second week of doing fishless cycling with acceptable readings. My ammonia is steady at 4PPM. No sign of nitrites or nitrates. My KH is 3. My PH is 8PPM. Water temp fluctuates between 68F-80F. 

Here is my question. When I first started the system, I raised the PH from below 6 to 8. I also raised the KH to 3. After the first week the PH went back down to below 6. The KH went down to a 1. Why did this happen? The ammonia did not change and the nitrite, nitrate levels are 0. Is there some other bacteria, that does not convert ammonia, doing this?

Your thoughts please.

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first off,, the Plant It clay has been found to contain high levels of sulfur... which will drive the pH down

did you happen to smell matches when you poured the media out of the bags?

if you did get some of this, the pH may never be high enough,,, ive had folks that had to replace their media entirely.

i like to advise folks to keep the pH around 8 for the first month or so, and let the bacteria kick off real good. then after a few months the system will go acidic and drive its pH down on its own.

it sound like the low pH has your bacteria at a stand still..

PS,, the best time to use river rock is in a scenario like this.. you can add 30% riverock to keep the pH higher..

. using 70% granite and 30% river rock,, i havent adjusted my pH in over 4 years

best regards.,

rob

Hi guys...to be fair Rob, I happen to be cycling 2 AP systems roughly the size of Richards (and about 8 smaller systems running various different methodologies)...both (and all) of them use Plan It clay...and I only wish that they had had any effect on pH and KH. We used well water from 2 different sources. Source no.1 had a KH of dH7 and a pH of 8.3, while source no.2 had a KH of dH5 and a pH of 8.3. None of those numbers budged at all until well into the nitrite spike phase. (I might have just gotten lucky and got a good pallet...but I've burned through like 15-20, 45 liter bags of the stuff in the last month and a half with no pH/sulfur issues).

Richards source water, with a pH "below 6" is obviously very soft and aggressive...able to neutralize the alkalinity and hardness that Richard introduced (think of it as the 'ol pH bounce that occurs when folks try to lower their pH with acid...only in reverse).

Just keep buffering up your water until it uses up it's ability to neutralize alkalinity.

Good Luck!

I would agree with what Vlad said here, it sounds like it just took a while for your buffer to finish reacting with the acidic source water. What did you use?

Yeah, good point Ryan...What did you use Richard?

A  bi-carbonate alkaline/buffer will generally take effect quicker than a carbonate source, BUT a bi-carbonate (although faster acting) only has half of the acid neutralizing capability  than a carbonate source does (so it will get "used up" even quicker).

If your sulfur was high enough to lower PH you would smell it. Sulfur is one of the chemicals humans can smell in insanely low percentages. Id be surprised if the sulfur was the problem with the PH with out the bag smelling bad lol.

Rob Nash said:

first off,, the Plant It clay has been found to contain high levels of sulfur... which will drive the pH down

did you happen to smell matches when you poured the media out of the bags?

if you did get some of this, the pH may never be high enough,,, ive had folks that had to replace their media entirely.

i like to advise folks to keep the pH around 8 for the first month or so, and let the bacteria kick off real good. then after a few months the system will go acidic and drive its pH down on its own.

it sound like the low pH has your bacteria at a stand still..

PS,, the best time to use river rock is in a scenario like this.. you can add 30% riverock to keep the pH higher..

. using 70% granite and 30% river rock,, i havent adjusted my pH in over 4 years

best regards.,

rob

Thanks for the input.

Vlad, I have used Potasium Bicarbonate and Calcium Carbonate to get the Ph and Carbonate levels up.

Rob,  I do not smell any sulfur oders coming from the Plant It Clay Media.

I have used rain water to fill my system. The rain water has a Ph of 6.5. Although I have raised the Ph to 8 with Calcium Carbonate and Potasium BiCarbonate, maybe the rain water is taking the Ph down again. 

Thanks

i did not catch the fact that the source water was so low. ..i was thinking he went from the normal 8ish down to 6..

FTR- i have at least a truck load of Plant It and it has never been a problem.. i will check the shop that told me about the sulfur and see what the story is on this.

like Vlad pointed out.. its just a matter of getting past the break point ....if you will.

i recommend river rock.

My system has been running for about a month. Its an outdoor system in an unheated greenhouse. So I have been battling water temperature fluctuations, Ph fluctuations, and some Newbie mistakes like adding too much ammonia because I failed to wait a few minutes before reading the API Amonnia test. I would say that the readings of the past 2 weeks have been acceptable. Not great.... but acceptable. Everyone says Cycling takes patients. So, I battle the conditions and wait.

Thanks for sharing your experience with me.

Yup, that rain water is quite aggressive it falls from the sky pretty much de-mineralized (except for some common pollutants that it pick up along the way...one of the most common being sulfur based pollutants...which only makes the rain water more aggressive and acidic). So once you neutralize that with alkalinity and carbonates it shouldn't fluctuate as much. Hehe, but by then of course your bacteria will be producing acids all their own which you'll have to buffer against. 

A lime stone (CaCO3) containing 'river rock' as a portion of your media just might be the ticket (if you can hit the right balance)...unless you really like fiddling and buffering almost daily.

I'm running 3 systems: IBC and 2- 45 gallon aquariums. The IBC is the oldest and maintains a PH of about 7.4. The 2 aquariums have a constant low ph problem, as low as 5.0. If I raise it by water change it soon drops again. All the systems get 7.3 ph de-chlorinated tap water. I use the aquariums as seed starters and the IBC has constant veggie growth. Nitrites and Nitrates are good on all systems. So can anyone explain the differences in my ph?

The sulfur issue was with plant!t. Plant!t it had a bad batch that was lowering peoples PH via sulfur and while I didn't see it where i work I did hear about it from the guy at the local hydro store who had to send back a pallet to plant!t. As fast as i am aware it was only a few stores that had the issue and plant!t recalled it before it made it out to any retailers but i did hear that from the guy at my hydro store. 

Rob Nash said:

i did not catch the fact that the source water was so low. ..i was thinking he went from the normal 8ish down to 6..

FTR- i have at least a truck load of Plant It and it has never been a problem.. i will check the shop that told me about the sulfur and see what the story is on this.

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