Muratic acid to kill rock

ecam · Dec 17, 2017

Hello all...

Im getting ready to kill some rock for my rebuild.... I wanted to know if muratic acid will kill and etch the rock at the same time. Or do i need to do the bleach to kill organics and acid to etch?

thanks in advance for the advise

Randy Holmes-Farley · Dec 17, 2017

Muriatic acid will kill organisms and etch the rock, but may leave some organic matter stuck to it.

Bleach will kill organisms and degrade organics (if enough bleach and enough time, most will dissolve).

ecam · Dec 17, 2017

how long do you recommend leaving the bleach? and also at what ratio will it do the job?

And after the bleach... will vinegar successfully etch the rock (if so... at what ratio).... im really hesitant to you the acid.....

PatW · Dec 17, 2017

Of course, Randy is a better source. I have had good luck with bleach at a bit more than a cup a gallon. Put in a powerhead and run for about 24 hours. Drain, clean off the rock with a hose. If it still looks funky, repeat.

Muriatic acid is a strong acid. It will convert the dry rock to CaCl and CO2. You could try a 5% acid solution. Or if you want to get aggressive go 10%. Just remember, you will lose some rock. When you do this, the rock will fizz. I would try the first run at 5%. If you want to get more aggressive run it again or do 10%.

Vinegar is a weak acid. It will etch the rock a little but not like muriatic will. You could run vinegar at pretty near 100%.

ecam · Dec 20, 2017

so... i just finshed bleaching my rock for the past week. I will be switching out the bleach for de-chlorinated (Prime) for the next week. im torn between using RODI and Tap for this process. My tap is registering .31 PPM phosphates. if i use tap... will i just be introducing phosphates back into the rock?

Randy Holmes-Farley · Dec 21, 2017

ecam said:
so... i just finshed bleaching my rock for the past week. I will be switching out the bleach for de-chlorinated (Prime) for the next week. im torn between using RODI and Tap for this process. My tap is registering .31 PPM phosphates. if i use tap... will i just be introducing phosphates back into the rock?

Yes, you will. It's not the end of the world, certainly, but some will bind that will only come off later in lower phosphate situations, like the tank setup. Maybe put some lanthanum chloride in the rinse water if you use tap.