Backyard Aquaponics
A place to discuss aquaponics

The pH has stabilised at 7.4 after only 4 days application.
The retiuculation will operate tomorrow evening so my readings (taken before the reticulation operates) should still be at 7.4.

More results tomorrow.

Good stuff Tony

Today we bought some phosphoric acid in the form of ph down from the hydro shop. 81% phosphoric acid, balance water.

We added 20 ml to an uncycled non offgassed 2000 litre tank of fresh bore water, with a drop from 8.2 to 7.6. We then added 5 ml to a nearly cycled goldfish tank (850 comets in 2000 litres), the result was a drop from 7.8 to 7.2. We feelthat the larger drop in the fish tank may be due to the large amounts of oxygen in the water ie there are lots of airstones, 3 airpumps plus return water from the biofilter... or maybe the hydrogen and sulfur gasses in the bore water effect the acid? Any thoughts? It will be interesting to see the reading in the bore water tank in the morning to see if the ph has come down any further.
Overall though, a successful operation, considering we have nute lockout now we can fix that problem

Measured the pH after the sprinklers cam on this evening. It was at 8.4 again, so I added another 200mL of the dilute HCl.

I will re-test pH tomorrow.

Tony, Why's the pH gone up again? did you topup with more bore water? or do the sprinklers sprinkle into the tanks?
What I'm asking is, if you haven't added water, what's making it raise.
Next thing I'm asking is why don't you set up a treatment tank, that you can fill with water, dump a heap of acid in to clear the ph, then add to your system.
forgetting the nitrate cycle here altogether, African Cichlids prefer a pH of 8 - 8.5
could I perhaps suggest getting Tilapia, since you're in WA?
Don't ask me about plants and nitrates at 8.5, it's not something I'm so ofay with.

Water with strong buffering will tend to return to the pH from whence it came. I had that problem with aquariums many years ago. I would add pH-Down, get the pH I wanted, and then the next day, it would be back up. pH is not good for fish. Be careful.

KP,
The pond is in the garden and gets a fair bit of water spray from sprinklers. While I have adjusted the sprinklers to minimise the effect, I still need to adjust the pH down after the sprinklers have been on.

The sprinklers were on yesterday and I added 200mL of my dilute HCl to the pond yesterday.
Today I have a pH of 7.4.
Nitrites are at 10, Nitrates 0.
If I can keep the pH around 7, I have a chance of cycling the system.

Janet,
That is why I chose a strong acid. It can deplete the buffering rapidly, even in a dilute solution.

Does anyone know of a suitable buffer to keep pH below 8.0?

Tony

nope.

maybe try incorporating some woody media?

does cocopeat also drop ph? i think its due to the tannins?

Coco peat/coir typically has a pH of 5.7 - 6.5 .....

there you go tony, put a bed of coco peat /coir into your system.

And expect your water to go black :-)

Tan

which is the colour it goes anyway in an aged AP

hmmm my water is already tan... I was trying to clear it by cycling more. It has had over a year of running (pumpless) with fish in it before I got going. Perhaps this is why my figures are so stable... So I shouldn't worry about the tannins?
I do dislike the tannin colour in my indoor FT... Need a metal halide to show anything up...

i quite like the tan colour of the muzza cod aquarium compared to my tropical one.

i think much of the colour comes from the food

yeah dark fish like large cats and murrays and other "mangrovey" (that's how I think of them) fish look great with low light and orangy brown water... but unfortunatley, that's NOT what DW wants in her lounge

beware the thumb KP it can only be effectively counteracted by the foot.