Backyard Aquaponics
A place to discuss aquaponics

Hi everyone, I'm having alot of trouble with my ph. Made a huge mistake and dangled some egg shells in a stocking which only put it up more. ( was trying to put it down ) I know, pretty dumb, but now I understand the ph thing a bit better. I read I could add HCL acid which i did and it came down a bit but it just went right up again. Ill take some photos when the sun comes up. Could I Use a food grade 33% hydrogen peroxide? I dont want to kill my nitrates. I have no fish in it yet. My system is about 1600 litres. Its sitting at about 8.2 - 8.5 ph. A friend suggested throwing a bunch of oxy shells in there. I put one in and was going to buy more today but after reading that alot dont like them at all even for aquariums I thought I should ask someone who knows what there talking about. Please help, I'm so confused!

How long ago did you fill up the system? Is it cycled? The nitrification process drives pH down, so time and patience are key, people with mature systems usually need to worry about raising pH, not lowering it.

Your water must be fairly hard (unless its your media), ie it contains minerals that maintain pH at a certain level, probably calcium, which is why when you added acid the pH bounced back; the acid got used up neutralising/consuming some of the minerals, but didn't get rid of all of them.

Make sure your media, if you are using any, is inert, otherwise you will have to get rid of it all!

Hydrochloric acid is the one to use, i'm not a chemist but that's invariably the advice given here by the experts, I would steer clear of hydrogen peroxide. Still, you don't want to overdo it with the acid. An alternative could be to partially replace your system water with rainwater, if you can collect it, which won't be hard (the water I mean), just make sure it isn't run off from a galvanised metal roof (zinc) or is potentially fish-unfriendly for any other reasons.

Yeah probably best not to use any more oxy-shells. Most aquarium products are manufactured with the idea in mind that people will be replacing their water rather than using bio-filtration to treat all of it, only topping up with new water, and for this reason they might harm your bacteria.

I hope this doesn't confuse you more! I'm not sure I've written it in the clearest way, but feel free to ask more anyhow!

33% hydrogen peroxide will definitely kill your nitrates, it's is used for sterilization and cleaning the system not to alter pH.

To lower your pH you need Hydrochloric acid, mix it in a bucket and measure the pH before you add it to your system. Take your bucket of water down to a pH of 6.0 and leave it overnight before adding it to your system.

Your pH will come down naturally over time, if you keep bringing it down, you'll then be having to buffer it up in the future.

I wouldn't use Oxy Shells or anyother products from the petstore in your system.

A sudden change in pH is detrimental to your fish, and continued exposure to high or low pH is likewise harmful. Goldfish thrive at the 7.2 - 7.6 range. Goldfish are able to withstand variations in pH much better than other fish, but even so, an effort should be made to maintain their water in this 7.2 - 7.6 range.

And as Danny says: Make sure your media, if you are using any, is inert, otherwise you will have to get rid of it all!