Sharing top-off return line with dosing line---Devil's Advocates???

FuzzySPS · Jul 10, 2015

Any reasons anyone can think of for NOT running a top-off line via a "Y" connector into an alkalinity (or, for that matter, calc or mag) line? I previously had problems (and read posts from others with the same issue) with the end of my alk line becoming clogged. Didn't matter if the end of the line was above or below the water line. Seems to me that using this "Y" connector scheme might solve the problem by having the top-off water flush the end of the shared line throughout the day as top-off water is required. It wouldn't cause any meaningful back pressure issues to either the peristaltic pump for supplements or for the pump in the freshwater reservoir, would it? I suppose it may cause a slight under dosing of the shared supplement (talk, calc or mag) if the pressure from the top-off line "prevailed" but this could easily be adjusted for over time by trial and error and observation/measuring. Am I missing anything or am I way off base in my thinking? Help, please...I'd test it myself but I am currently tankless and am diagramming my proposed set-up to return to the hobby. Any meaningful feedback is much appreciated. Thanks for your help.

P.S. I plan on going sumpless so this would also save me precious inches as I am trying to conceal heaters, dosing line holder, and Tunze Osmolator in a custom made "box" within the tank that I want to be as small as possible so as not to detract from the living contents of the display tank.

saltyphish · Jul 11, 2015

samba_dad · Jul 12, 2015

That is an interesting idea. I struggle with my alkalinity line clogging. The challenge i have is that my alkalinity source has largely become my freshwater top off as well. I think your concept works in theory though.

redfishbluefish · Jul 12, 2015

Y connectors aren't smart. How is whatever you are dosing going to know which way to go when they get to the Y? You will end up dosing your top-off reservoir.

I also what to be clear and make sure I understand your full concept.....you are not sharing this same line with all components. If so, the sharing of Alk and Calc will cause for precipitation from any residual left in the tubing. And again, the Y connector where the Alk line meets the Calc line would be plugged by immediate precipitation of carbonate. Again, don't believe you outright said this, but just wanted to throw out this though.

FuzzySPS · Jul 12, 2015

redfishbluefish said:
Y connectors aren't smart. How is whatever you are dosing going to know which way to go when they get to the Y? You will end up dosing your top-off reservoir.

I also what to be clear and make sure I understand your full concept.....you are not sharing this same line with all components. If so, the sharing of Alk and Calc will cause for precipitation from any residual left in the tubing. And again, the Y connector where the Alk line meets the Calc line would be plugged by immediate precipitation of carbonate. Again, don't believe you outright said this, but just wanted to throw out this though.

Top off and calc lines only would be shared; other components would have dedicated lines. Don't see why the concept would not work, especially if a check valve were put in the top off line slightly before the "Y". When the peristaltic pump calls for alk, it runs up the common line to the sump (or tank, in my case). Same happens when top-off water is called for. Once in a blue moon, they will be coincide and run up the common line simultaneously in which case the top-off reservoir's pump pressure would likely prevail. Absent that, I would think it would work for the reasons just described. Certainly not trying to be argumentative as I am by no means a plumbing guru and am very appreciative of your reply. Based on what I have said, are you still of the opinion that it would not work?