Is this citric acid safe?

[fishkeeprian]

Is this citric acid safe to use in my power heads?

What is the normal ratio to use?

Thanks

Sent from my iPhone using Tapatalk

 

[Vinny Kreyling]

Yes but you need quite a bit @ once.
I did 2 cups into a 5 gallon container about 2 gal. with 4 small Tunze PH in the water.
I used the magnets to hold them on the can & ran them for a few hrs. Came out very well.