Backyard Aquaponics
A place to discuss aquaponics

have finally upgraded the sun roof for the FT.

and I also modified the solids filter from a straight radial to a swirl / radial

collects a lot more solids which I pour onto the dirt garden.

I would imagine carbonates would create carbonic acid. Which would temporarily lower ph. it would also make your water into soda, and be all fizzy like, but not in an oxygen rich manner. It would be fizzing co2, just like your favorite fizzy drink. Unless your favorite fizzy drink is Guiness, which uses nitrogen.

My favorite fizzy drink is beer. Now that would be something beer flavoured fish.

Your favorite fish recipe does not include BEER batter?

Seeing your tented pool makes me think of putting a deck over the pond part. with the grow beds on the far side of the deck. I would then put a wooden ramp down from the deck to the dry side of the pool to have a complete circular pool to skateboard in with a launch ramp:)

Absolutely,

Oil fumes is one reason for it being unsafe, the other is the poisonous gases Carbon Monoxide and Carbon Dioxide- both are produced by the hot compressed air oxidising the oil. Divers must use air compressed with oilless compressors.

getting back to the high pH and carbonates, in my research on carbonates there were hydroponic sites using sulphuric acid to lower pH rather than HCL which I and others have used.

It happens that I have 250ml of sulphuric acid in my shed that I really should dispose of.

obviously only going to use small amounts to gradually reduce the pH of my FT, has anybody tried using sulphuric acid or know why I shouldn't?

If you've got it... and are only going to use it for top ups.. then use it...

The "con" is the addition of "sulphates" to the system...

As Rupe Says the Con to sulfuric acid is Sulphate.
The Con to HCL is the Chloride

Deciding which is most appropriate might depend on what else has been or is likely to be used in the system and what you are growing. Too much of any one thing can often be a problem as this is all about balance. Some plants are very sensitive to Chloride (hence why in some situations it might be better to use Potassium Sulfate instead of potassium chloride and so forth) and if you have perhaps already salted the system for some reason, then avoiding heavy use of HCL might be appropriate.

Now Rupe, I know Hydro uses a lot more sulphure than Aqua, but would you share what levels of Sulphates would be a worry for the fish or perhaps share how to figure out how much sulphate would be too much?

The chloride is really not a "con" at all... it's an important element in plant growth... mitigates against nitrite poisoning.. and promotes slime coat production

Acid adjustment should only be done to top up water requirements anyway... and shouldn't really amount to anything significant even if the system is already salted... (in which case the existing salinity would be reduced with top up dilution anyway)


Sulphates aren't really that great a problem for fish... but can cause ademna in plants...

The use of sulphates in hydroponic nutrients.. particularly the original Hoagland mix.... is more for the pH modulation.... (personally I never used high sulphate mixes)

Using Sulphuric Acid for top up water isn't a real biggie... it's just that Hydrochloric Acid is generally more readily available, cheaper... and beneficial..

From http://www.lenntech.com/applications/ir ... -water.htm

"Injection of sulfuric acid to dissociate the bicarbonate ions (PH around 6.2) giving off carbon dioxide. It allows the calcium and magnesium to stay in solution in relation with the sodium content."

Well it's hopefully only until I get the liner fitted!

I may be able to borrow some fish tanks which would enable me to drain and refill with fresh water during the liner install, that fresh water would need to be de-chlorinated and neutralised.

or would it be better leaving say 2/3 of the water in Ft and only topping it up?

Then there is the stress (on the fish and me) of catching all the fish and putting them in a small tank.

This winter, with the rain we have had here I have pumped probably 3 or 4kl out of my FT so far.

BTW have not checked the rain water but the tap water is pH 8

That chemistry is true for any pH acid buffer addition...

Rain water is generally more acidic or at least devoid of most of the carbonates and bicarbonates so collecting and using rain water instead of your tap water would likely be a good way to bring pH down.

I've run into climbing chloride levels in my system last spring and the strawberries were not thriving. There is some chloride in my well water apparently and the use of hydrochloric acid to reduce the pH didn't help. I was very careful in that system to avoid adding any sodium chloride because of the strawberries but apparently the use of the HCL and a horrible lack of potassium the strawberries totally didn't thrive.

Can you let us know what some of the symptoms of ademna in plants we are likely to grow in aquaponics might look like? I'm actually looking at using potassium sulfate to bring my potassium levels up but I've had a hard time figuring out how to tell if my sulfate levels are getting "out of hand" and so far I've only found things talking about symptoms in ornamental greenhouse grown crops.