Dosing Kalk - Line Size

[wake74]

Not exactly a chemistry question, but I know a lot of people in this forum have experience with kalk.

I've been toying with several freebie pumps to dose kalk but finally purchased a used Masterflex Pump (6-600 rpm, digital). Its one of the new models that takes multiple sizes of tubing with the same head. It is a for a mixed 65 glln reef with sump. Tank evaporates about 2 gllns per day. Pump works great for creating slow drips.

I purchased the LS13 tubing for the pump which has an ID of 0.8 mm, which is very small but gives me a good flow range. However, the tubing plugs within a couple of days of use. If I cut off both ends, I can only get another day or so, before the tubing is unusable.

A couple of questions:

1. What is everyone using for tubing? Specifically, what ID with what flow rate?

2. Are you discharging above the water, below the water, or below the water in a high flow area?

3. What materials are people using for their peristaltic pumps? The Masterflex name brand tubing is awful expensive, and I'm thinking about just trying a few from McMaster-Carr.

4. Any other secrets to reducing tube clogging?

Thanks,

Glenn

[Randy Holmes-Farley]

I don't use a peristaltic pump, so my tubing is unrelated to my delivery rate. That said, I use 3/8" diameter tubing (IIRC). It is pretty large, and even as is, it gets clogged over the course of a year or so with loose CaCO3/Ca(OH)2, so I run some acid through it once in a while.

You should discharge above the water line so it drips (IMO). The end clogs, but not as badly as if it were under water.

[wake74]

Thanks Randy for the follow-up. Your 3/8" tubing is over 10x larger than what I am using, so maybe that explains my clogging problems.

[Randy Holmes-Farley]

Yes, I think that is likely.

You're welcome and good luck. :)

[DrBDC]

What kind of drip valve are you using on the tube Randy? I'm getting the same problem but mine is my valve getting all junked up even though it is above the water. I'm using standard air tubing too.

[Randy Holmes-Farley]

No valve at all. I use a 3 gpd diaphragm pump (a Reef Filler) and the limewater just runs out the end.