Not recommended. pH-up is usually potassium hydroxide (KOH), and pH-down is phosphoric acid (H3PO4).

In fish tanks you might use bicarb of soda as a pH-up, and filtration over peat/oak leaves to bring the pH down.

I had just the opposite problem. I have had to buy the Ph Up and Ph Down from Petsmart that was made specifically for aquariums.

I can't find it locally for hydroponics but I am only trying to balance 5 gallons of nutrients per day.

So Ph Up and Down do make a product specifically for fish and you can buy it at Petsmart for one store.

Connie

Usually in aquariums the ph has is always going down this is due to the fish and the good bacteria that filter your water giving of co2 in the form of carbonic acid. So for your genera aquarium you would only have to bring your PH up 7.0 -7.4 is a good range. A even simpler way is to have some sort of calcium carbonate source in your aquarium this can be in the form of sea shells this should dissolve when your PH falls and bring it back up again to around 7. You can also get shell grit (crushed up shells) from pet stores and put that in your filter, make sure you give it a good rinse first though.

Hope I haven't babbled on too much and confused you.

Cheers

Fil

I've used a butter knife to turn a screw on many occasions, but that doesn't make it the right tool for the job.

Whether it's fish or plants, best to use the right pH tool for the job.