Backyard Aquaponics
A place to discuss aquaponics

Ok, begs the question then guys... it's been raised before in several threads for one reason or another....

Do you think there is merit then in removing "some" solids from the system by using seperate "bio-filters" or skimmers and regular small water changes??

By doing this you are also removing the good stuff that the plants will grow from - and remember that biofilters will not remove any solids unless you flush them.

It really depends what you are trying to achieve. I want a no waste system. ANy water removed will be for use in dirt gardens.

Goes without saying...

meant in context of pH fluctuations, or do you think the use of buffering agents (pH up / shell grit etc) has more benefit, and/or is just as controllable?

simple answer?

NUP!

i got no probs with adding shells all the time.............whats the point in growing high calcium foods when there ain't no calcium for 'em to uptake?

i've tarted collecting my egg shells, amasing how quickly they build up!

First, I am confused. Steve said a while back that the formal member systems were for systems where no more posting would be done. But obviously, some very active topics are here. Can someone reiterate what the criteria is and what I misunderstood?

Now to the topic. When I visited Dr. Savidov this summer, one of the things we discussed was system pH levels. He is doing things different from the accepted practice on pH. He is running at 6.5 on purpose with tilapia and basil. He said it had very good affects on the basil and the rest of the system worked fine. The bacteria would prefer higher pH, but are 90% efficient at 6.5. The ammonia is less harmful at that pH. He said the iron enters plants much more efficiently at this pH and no chelated iron is necessary in his system. The veggies love 6.5 and the tilapia are OK with it. Do some other fish find this pH stressful?

I am very interested in this and I startup my system in a few weeks(hurrah!) . My well water is pH ~8 (meter on order). I will let it sink to whatever it will naturally (at least to 6.5). Perhaps my system will do fine without pH alteration. The makeup water will always pull it up and the bacteria will pull it down. It is great when we can let things run naturally. We will see if this is a good idea. Again, I want to leave my system unattended for multiple days (weeks?). No pH adjustments is one more step in that direction.

What do you all think?

"Formal" means we're not supposed to banter. "Completed" are ones that are locked so no one can put any posts. The "Completed" threads have been cleaned of banter.

Different fish have different tolerances for a range of pH. Tilapia are particularly tolerant of a wide range. With the except of Rift Lake cichlids though, I think most fish could handle 6.5 pH easily as long as their introduction to it was gradual. I would test your water parameters to see what you're working with for pH and buffering, consider putting crushed shell in to pull pH up and increase total buffering capacity if needed, and then leave the pH alone as much as possible. If you can run the system at 6.5 - 6.8 without excessive toying with the pH, go for it. The veggies should love it, the fish and bacteria will be fine. The thing you don't want is to bounce your pH all around trying to force it low. (Been there, done that, killed a lot of fish.)

Thanks Janet. I appreciate the info.

My well water is very buffered. It is amazing how hard it is for me to lower it. Perhaps I will find that my system will not go below 7. We will see.

So if My water is 7.5 ph, it is good for the fish and bad for the veggies? Might explain some of my problems with veggies.

DT, Yes, your veggies would appreciate a lower pH, but let your system mature a bit more. It will drift down over time. I'd hate for you to get fuzzy fish again by trying to force the pH.

I run my pH at 7 or below.....usually 6.8.....and I find that I can more effectively avoid the consequences of ammonia spikes. Ammonia is less toxic at lower pH (see Ammonia in Important Information section).

My perch seem to have no problem with PH of around 6 and the bacteria is clearly working with 0 ammonia and very little nitrite this morning. I might aim for PH of 6.5 like Savidov. Thanks for the info Doug.

6.5 would be better for the plants, but two points come to mind

1) it doesn't leave a HUGE amount of down shift lee-way

2) it is very easy to buffer to 7.0 and not check it for months............what would you use to buffer your system to 6.5? And if its not buffered then it WILL drop further.

These are the specs in the info section that i found about nitrifying bacterial, although yes, there probably are different strains.

At pH levels below 7.0, Nitrosomonas will grow more slowly and increases in ammonia may become evident. Nitrosomonas growth is inhibited at a pH of 6.5. All nitrification is inhibited if the pH drops to 6.0 or less. Care must be taken to monitor ammonia if the pH begins to drop close to 6.5.

VB, this might explain why with your heavy feeding the bacteria could not increase in colony size, but could still process the ammonia once you dropped to your usual feeding. Wha u think?

Maybe - time will tell. Haven't got out there to do a test tonight. I will definitely add more shells cause I do want a buffered system.

Did the tests tonight. 0 ammonia, 0 nitrite. PH is still low so I am continuing to add a small amount of bicarb of soda each morning and night.

Fed the fish a decent serving of pellets tonight.

VB, is bicarb of soda ok with fish?

Aussieponic