Backyard Aquaponics
A place to discuss aquaponics

Was wondering about that myself, most plants prefer < 7pH and fish are 'safer' and under 7 as well, dont know any reason for keeping it above.

just for the fish eh?

I'll review the previous post, can someone please poke holes in the following theory-

given a larger biofilter area to account for reduced efficiencies of nitrifying bacteria, plants will grow better (generally better trace element uptake) and fish will be safer (from the effects of toxic ammonia) in a system where the pH is less than 7.

http://www.backyardaquaponics.com/forum ... .php?t=133

check out the ammonia toxicity on this thread in the chart. Supports your comment that ammonia is much less toxic at lower ph levels

Yeah read that, it follows what we learned.
If you keep your pH under 7, toxic ammonia will 'never' a problem. I've got some study notes like the attachment, but showing the grid at .1 pH and .5 temp, will find and post it later.
I assume there must be a good reason to keep the pH above 7, just want to know what it is

* never doesnt actually mean never...

Check out bacteria growth under about 6.5 I think from memory it suffers pretty badly, could lead to a crash

So i guess you would want an oversized independant bio if you wanted to take advantage of the above

In my mind which aint always so good yer cycled systems wont have any ammonia and
bacteria like a ph of 7.5 - 8.6
fresh water fish 6.8 - 7.2
all from some fish site
By keeping the ph around 7 you keep every thing happy and if your well buffered can avoid crashing the colony by swinging too low as Stu states.
So I'd guess its for both the fish and bacteria, while not being so concerened with matching ph for the plants you plan to grow.

Dont know about the fish prefering basic, i know of a system that has run silver perch (with a working bio) at low 4's. It was unintential and soon rectified but the fish were still feeding well.
Are those bacteria figures a preference for effiency? Anyone got any specifics on how much the drop is below 7?
Id be interested in running < 7 for the safety factor (you're right, a good system should have no ammonia, i dont assume Im going to have a good system for a while) and want to know if im going to loose that much bio efficiency

I think thats the prefered range for them.
Its my understanding the perch can handle 4.6 - 9.5 but handling and loving it are two different things. When the problem was rectified what ph did they strive for?

the system usually runs at 6-7, but it is an aquaculture only facility with large biofilters

Food for thought, seems like it would take longer for your bacteria to grow by running a lower ph and there by take you that much longer to ammonia cycle your system.

Yeah, maybe start at 7.5 or so and bring it down over time, although starting the cycle is going to be the only time you actually want ammonia in the system.

It's all a balancing act really. I think a series of comprimises will see us with well balanced and stable/mature systems

I agree, its just easier to balance on a wide beam vice a narrow ledge. I have no idea what I am talking about either, just wish my worms breed faster so i could feed my perch properly. Nite all.