ATI Doser DP-6 - tube keeps pulling in air

Happyschneider

New member
Hi all,

need some advise, not sure I am in the right forum. I got myself a DP-6 dosing pump from ATI. In theory it is all good if somewhat noisy but I get over that.

My issue is with the fact that the tube sucks in air where I have it and the bubbles rise in the tube and basically prevent future dosing that just keeps pushing the air around. I tried by cutting the end of the tube differently, putting the pump itself above the outlet (I don't have a sump so now the pump is on top of a shelf with tubes hanging between the tank and the shelfing unit. Today I thought I try to add one of these auto drip nozzles from the watering system for the garden at the tip as I thought it might help if the outlet is smaller.

None of these hacks seemed to help. Still, as soon as I have removed all the air from the tube, the liquid (alkalinity from 3 part dosing) starts dripping out of the tube and the bubbles rise (about 3 inches in). So the pump is just pushing air around for the next few dosings and I don't really have small dosages. I would highly appreciate any ideas that could help me.
 
The hose has to be @ the bottom of the container submerged.
If it pulls air like this there is a hole in the tubing.
You could put a fitting through the bottom of the container & do it that way also.
 
That's a very common problem with most dosing pumps. When the head starts moving, it also sucks a little air, and the air slowly rises inside the tube.
That's why some more expensive brands come with their own check-valves, that should be put in the last part of the tube. I.e, my Kamoer pumps.
It has nothing to do with putting the tube touching the bottom or not. It's just something to do with the movement of the head.

For example, Jebao dosing pumps are known to suck air. I had one of this and I had to put check-valves in the last part of the tube, and the problem was solved.
The check-valves you should use must have no metal, the CO2 plastic check-valves for planted tanks are perfect.
 
Duna - when you say check valve is to be put at the last part, do you mean the input end that goes into the dosing container or the output end that goes into the tank/sump.
 
Ok, the tubing is pretty tight on the connection bits. I won't get it on any better than that. The end in the container is completely submerged, so no air comes in there.

I can observe that at the end over the tank, a drop forms after the pump has stopped and falls into the tank. The air bubble then rises to the highest part of the tubing and keeps accumulating until I have about 5 cm of air in the tube.

It does not happen all the time but defeats the purpose of the dosing pump somewhat if there is a lot of alkalinity going in the tank attached he same time and then nothing until the dose has pushed out the air bubble and then a lot at once again.
 
But thank you everyone for the input. The way I see it, is that it is a problem of surface tension. I will try to put a needle at the end over the tank and see if this helps.
 
Hi

At which end have you put in the check valves - both or only the output end?

Not both, only at the end part of the tube, the part that goes from the pump to the tank. You can put it next to the pump or at the end of the tube, it doesn't matter.
 
How has the ATI DP-6 held up for you?
Does it keep it's calibration long?
I am planning on using a doser on one of my tanks.
There are really no reviews on this ATI DP-6, maybe because it's a rebranded jebao.
 
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