Backyard Aquaponics
A place to discuss aquaponics

I suppose the key point is that food grade is mentioned, but I doubt those sold at aquarium shops are food grade.

Sory guys i meant to write sodium biphosphate, not bisulphate where are those damn glasses . .

biphosphate is harmless to humans in low quantaties, but now i read up on it, it is used as an antibiotic . .hmmmm
i may just go see if there is any correlation between a spike in my ammonia and adding some in...
fyi it is also known as Methenamine

There's so much stuff added to food that's "supposedly" safe... it's hard to know just how safe "safe" is.... any the more studies that are done... the more "unsafe" a lot of things appear to be...

That's one of the reasons I like AP so much... you don't really have to add that much that isn't natural.... to produce abundant food...

I would recommend being careful how much you use of sodium biphosphate, the phosphate gave me grief with algae blooms for a couple months until I had changed enough water to get it down to more reasonable levels.
Before I tried dropping the ph the algae had been minor.

Yep, thats a very good point... that's exactly what happens in our town supply dams, and rivers generally, after rain.... phosphates, from fertilisers, runoff into the systems and trigger an algael bloom...

Well personally I am cycling a system right now, stocked very lightly and I have not bothered checking the pH.

To me over time, the pH will drop and the next battle would be keep it up so that the test kit can provide good reading.

As long as the system shows signs of the cycling process, the bacteria is growing. Possibly not in the ideal conditions but nature will find its way. Swinging the pH could actually have adverse effects on the bacteria strain that has already established itself and possibly prolonging cycling.

And if I am reading it correctly, Rupe's earlier advice on lowering the pH is not because the pH is high on its own, but it is because the ammonia levels, temperature and pH combined makes ammonia toxic. Lowering the pH will make ammonia less toxic.

Spot on Ivan... pH will drop as the system cycles and matures... although adjusting the pH might help with the "cycling"...

But you read it correctly... I was suggesting moving the pH to bring the ammonia toxicity within acceptable limits...

just out of interest (and sorry for all the spam hillsy ) what do you keep your ph at? mine sits on 6.4 - 7

Rob,
Yeah gravel did come from the soil place in Ellenbrook. Can't seem to get the PH below 8, normally sits around 8.2.

I actually bought some PH down which is sodium bi phosphate yesterday as I thought it would be safer then HCL. Gave the tanks a dose yesterday and again this arvo before reading the previous posts and already can notice the tank has gone a little green around the sides. Covered with some extra shade cloth for now and will monitor how it goes. Guess that was another waste of money then should have stuck with the cheaper HCL option.

Hillsy,
I will let you know how I get on with the HCL. I have not found large traces of Limestone or Dolomite in my crude test with vinegar, so may only be temp. issue.

Cheers Rob.

depends on what you are growing. different plants grow better with different PH.
in general 7 should keep everything happy but I'm pretty sure a slightly lower ph has been proven to have the best effect. No lower the 6.2, but some where between 6.4 and 7 is ideal.

Regards
Matt

Since adding the pH down all my cabbage, broccoli and cauliflowers are looking really sad. I added a dose of PH down on Wednesday and again on Thursday, and managed to get the PH down to about 7.8. Nitrates/nitrites were still through the roof so salted the system on Friday (about 1ppt). They are the only things I have added to the system and since then my PH has come back up to around 8, the water has gone green and I have some sad plants. Tomatoes and beans etc still look fine and I have spring onion and carrot sprouts starting to shoot up but cabbage, broccoli and cauliflowers were looking really good a couple of days ago, now the look pretty bad.

Any ideas? Fish still hiding in the corner behind the tank outlet. No deaths but getting hard to see them again in the green water. Thinking of doing a few water changes using water from the lake down the road rather than dosing up the PH with tap water again?

hillsy im not expert on plant diseases but that might be a mildew on your broccoli . .

Few more pics

Freoboy,

Yeah I have no clue when it come to the plants but don't think its mildew. The leaves have actually dried out. Did have a few hotter days maybe they are sun burnt?