Backyard Aquaponics
A place to discuss aquaponics

Just to be clear on what i understand. Dont add any chemicals to adjust PH? Just let it come down over time as mine is 8.2??

Ive no fish in system , so would i damage plants by adding an agentvto bring PH down?

>> I've no fish in system , so would i damage plants by adding an agent to bring PH down?

don't add any commercial or aquarium products to a AP system to bring pH down.

It is discussed widely on this forum - search on hydrochloric acid or muriatic acid (same thing)

basically you need to treat water out of the system and then once stable add it to the system.
Do this by getting stock standard HCL (hydrochloric acid) from Bunnings etc and adding it to the water and allow to stand for 24 hours, then test. Hydrochloric acid has no side products other than NaCl and water. Fish can handle the small amount of salt produced. Do not add the acid direct to the system.

Initially you will need to work out how much acid to use. Initially it may appear to come down and then come up a bit - hence the 24 hour wait. Once you know roughly how much then you can dose new water quite efficiently.
Keep in mind that water supplies do vary over the year and may be higher pH in summer when coming from groundwater and lower in winter when more dam water is available.

As you have no fish you could drop the water you are adding quite a bit to say pH6.5, however when you have fish the chnages in the pH must be kept small as pH changes will stress and kill them.

You are in Victoria, but if in rural area then you may have chlormines in the water.
(check with you water suppliers web site - not as common in Australian cities as US etc, but is used).

p.s. to above. I note on previous page you have posts that suggest an added buffer.

you can also take water out of system treat and put back, as you don't have fish probably wont matter much if you do a big chunk but best outside of the system. And keep pre-treating any top up water.

But you need to keep an eye on the system generally as it will still drift back to the system pH until the buffer is sufficiently used up. (this presumes it is not media and just water). If it were me I would initially just focus on dropping the system to around 7.6 or so and getting it stable there first and then maybe get some fish back in.

we are moving to winter and typically that is a time when pH often drops naturally anyway.