Dosing tubes in water or above?

[J Rog]

So this maybe a dumb question but I have always had my dosing tubes for Alk, CA, and Mag in the sump under water.. Been doing it as long as I had it (2011).. But Im wondering if others keep there tubes under water or just above the water.. Is there a difference? I do notice after some time there is a little alk that hardens and blocks up the tube.. Im wondering if its because its being dispensed under water..

 

[veselym]

I keep mine out of the water...it could back siphon and make it harder for the pumps

 

[mike007]

I keep mime above the water so that If something goes wrong they will not siphon the water out.

 

[cdness]

If my alk tube falls into the water, I see the alk precipitate a bit. Then it looks like the precip will actually move up the pipe. I do my best to keep them out of the water.

Back siphoning is a good reason to do that too...

 

[J Rog]

Aww looks like im alone on that one. lol I will move them out tonight. Thanks for the advise guys!

 

[ARVERLY]

above the water

 

[DRThompson]

I use to dose mine above the waterline. I would get a build up on my return pump.

Now, they are in my bubble trap in my sump (under water) I've found that I get less build up on my return pump

 

[Randy Holmes-Farley Verified Community Expert]

They should be out of the water. The reason is that you do not want tank water to enter the tubing and precipitate calcium carbonate in the high pH, high alk, or high calcium setting.