Dosing pump-safe carbón source?

[jbrady429]

Hey everyone,
I’m looking for a carbon source (I.e. vodka, vinegar, NoPox, etc.) that won’t destroy dosing pump lines and that I don’t have to keep refrigerated. I’m not interested in using pellets. Does anybody have any recommendations?

 

[Dkeller_nc]

The answer depends rather sensitively on the composition of the dosing pump lines. If they're silicone, you can choose any carbon source you choose - acetic acid (vinegar), ethanol, methanol, etc... About the only thing that silicone is susceptible to is concentrated basic solutions (such as sodium hydroxide).

If the tubing's clear vinyl (i.e., clear PVC), the answer's a bit more complicated. PVC (rigid) itself has poor chemical resistance to acetic acid and ethanol. However, clear PVC tubing has a bit better resistance. And dilution of the substance typically improves resistance. I haven't tried it myself, but I suspect diluting ethanol to an effective concentration of 20% would prevent microbial growth and protect your tubing. That's drinking ethanol, btw - ala vodka or everclear; never use reagent ethanol, which is always poisoned to prevent its untaxed consumption by us humans.

If you find that 20% ethanol over time causes hardening of the tubing, switching to silicone airline tubing is easy and cheap.

 

[jbrady429]

The answer depends rather sensitively on the composition of the dosing pump lines. If they're silicone, you can choose any carbon source you choose - acetic acid (vinegar), ethanol, methanol, etc... About the only thing that silicone is susceptible to is concentrated basic solutions (such as sodium hydroxide).

If the tubing's clear vinyl (i.e., clear PVC), the answer's a bit more complicated. PVC (rigid) itself has poor chemical resistance to acetic acid and ethanol. However, clear PVC tubing has a bit better resistance. And dilution of the substance typically improves resistance. I haven't tried it myself, but I suspect diluting ethanol to an effective concentration of 20% would prevent microbial growth and protect your tubing. That's drinking ethanol, btw - ala vodka or everclear; never use reagent ethanol, which is always poisoned to prevent its untaxed consumption by us humans.

If you find that 20% ethanol over time causes hardening of the tubing, switching to silicone airline tubing is easy and cheap.

That’s great information. I’ll check the tubing used in my dosing pump heads and get some silicone tubing. Thank you!