i secure mine just enough that it don't fall off. it dont matter how u do it.
i like to have a an inch or so out of the water. this is in case theres a back siphon which shouldnt happen but it doesnt hurt to take extra precautions.
Here are some pics of my setup, I've been using the dosing pump for about 2 months and love it.
The unit is mounted to the roof of the stand
The tubing is tied around the plumbing and the CA and ALK are tied together
Another view
My CA and ALK containers
I have the ALK and CA dose every hour for 5 seconds. They're on 15 minute intervals. The ALK goes first, then 15 minutes later the CA goes. This works great until there is a power outage and the Aqua Medic Doser loses the interval and you need to reset. They say it's on their list of fixes.
Fluidimagery....Really nice setup! Great use of space. I like the idea of have the tubes at the top and just drip down into the sump. I might have to copy your dosing pump setup.
Thanks guys, I'm open to questions if you have any. The only issue I have on occasion is that the alk portion gets built up on the end of the tubing. Every week or so I'll just clean it off and it seems good.
This is my 3rd tank and since adding the dosing pump I've never seen coraline growing like it is so fast. IMO a very worthwhile investment.
Nice set up! I would do the same thing fluid did. I think its a good idea to have it like an inch or two from the surface of the water so you can see the rate and make sure its working.