Excellent post. Thanks to all for the info, as I am about to by my first doser.

I use two Drew's Dosers from BRS for calcium and alkalinity, these dosers don't back siphon at all. I have them each hooked up to a digital timer. I use the Fauna Marin balling salts. I dose magnesium into my water change water, and am now just noticing this isn't keeping up anymore, so I should buy a third doser. These dosers aren't as cool as the Profilux with all the digital fanciness, but they are reliable and are much more cost effective than the Profilum SA dosers. I was looking at Profilux, but decided on Drew's Dosers because I couldn't justify the extra cost.

When comparing how much each person doses, keep in mind that people use different concentrations. I mix up a 5 gallon pail of each solution that I keep sealed to prevent evaporation. I have 3.5 liter jugs attached to the dosers, and I just use the 5 gallon pails to fill them up. I dose about 80 mL of each solution per day split into 3 doses. Calcium during the day, and alkalinity at night.

I don't get any sort of crust on the ends of the tubing, the ends are out of the water. I hooked up these dosers in April I think, I haven't cleaned them yet, and it doesn't look like they need cleaning.

Oh, and the "chambers" are just expensive containers to hold the dosing solution. I use Rubbermaid containers with a small hole drilled in the top for the airline tubing.

+1 to Myka - get the drew's doser or the BRS two part ones (may go back on sale on boxing day to 69.99 each as per black friday so hold off if you can. I dont believe doser's can back siphon just given their design (liquid is pinched out in one direction) It's not a free flowing tube so its not like the return line in your tank. I am going to use some snazzy VOGA wine bottles i have laying around as dosing containers;

http://i992.photobucket.com/albums/a...l/P1010110.jpg

All I have is a SA2.... Very easy to adjust:biggrin:.....I needed very little MG so I couldnt justify the extra cost to dose that little bit of Mg.....in hindsight(and I know I can add a pump if I wanna) the third(or fourth) can be used to drip a steady stream of phyto or how bout this.....us Zeoheads could come up with a solution containing all the Zeo foods(Extra CV SP AA and CS).....and dose that 24 times a day:spy:

Some dosers will back-siphon because they use fewer rollers. Dosers should have 4 rollers to prevent back-siphon. Some only have 3. Drew's Dosers and Profilux both use 4 rollers.

So I solved my crusty hose issue =)

I dose into my external overflow box and I had the outlets very close to the weir so water coming over it mixed with the dose. With the addition of the wavebox the water was actually washing over the pipe's end every now and then and this I think was causing the drip leftover at the end of the hose to skin over.

I'm a regular lurker on this site but I felt compelled to post on this topic. I bought an sa3 and I use the third pump for evaporation water instead of an auto-top-off unit. Works awesome and without the risks associated with ATO failures. I was always curious why no one seems to do this but I haven't found any downsides yet.

It isn't recommended because dosing pumps aren't designed to run that much. On a tank with a lot of evaporation the dosing pump wouldn't keep up anyway. If it works for you though, all the power to ya! :D

That's cool that you can pull that off with your doser. I evaporate about 8 gallons every 3 days so I could not imagine trying to run that much volume through the doser. That certainly would shorten the life of the motor dramatically. Also, the amount of evaporation varies from day to day. I would find that difficult to manage with a doser.

I knew there must be a reason people don't us them for evaporation. My tank is an open top 110 gallon evaporating a little over a gallon a day pretty consistently. I guess I'll have to see how long before the pump craps out but for the $100 to replace it I thought it was worth trying - might be a good solution for smaller tanks.