DIY Manual Quick Doser

**TKS7011** · 1st Jul 2009, 13:46

To reduce time and make manual dosing a little bit more convenient, I have this idea of a 'quick doser' in mind for my 5ft planted tank. The attached diagram explains the idea. When tap is on, holding tube could be filled in 2-3 second to desired level. Though some will drip away from nozzle during the process but the amount should be negligible (as compare to 10-20ml dose for my case). Fertilizer in the holding tube takes few minutes to drip and dispense into tank water.

I am building up a prototype and will post the outcomes when ready. Comments are welcome

**Shadow** · 1st Jul 2009, 13:54

why not add electronic valve and timer and automate the whole thing

**TKS7011** · 1st Jul 2009, 16:37

Originally Posted by Shadow

why not add electronic valve and timer and automate the whole thing

Well, that was the initial plan but due to cost (good reliable digital timers are not cheap), I'll go for 'wireless'

for now and see if I find it convenient.

**BFG** · 1st Jul 2009, 17:53

You could use an opened syringe without the plunger and placed it where the plastic tube is located in your diagram. Make it easy to see how much you are dosing.

**TKS7011** · 1st Jul 2009, 18:16

Originally Posted by BFG

You could use an opened syringe without the plunger and placed it where the plastic tube is located in your diagram. Make it easy to see how much you are dosing.

Thanks for your feedback. Good idea! Will proceed with whatever available material first. And improve further if it works.

**TKS7011** · 2nd Jul 2009, 23:04

Hi,
Completed a prototype consists of 2 dispensers (1 for macro and 1 for micro).
Took 3-4sec to on and off tap per dose. More or less meet my expectation, quite happy

Have to monitor further for its performance.
Thanks for reading!

**Alvin Koh** · 3rd Jul 2009, 01:40

The construction of your prototype is very solid! Almost looks like a final product.

Your idea got me to thinking about another method - which is commonly used - the pump bottle. However, perhaps the bottles can be encased within a large PVC cyclinder with a timed weight/downforce above the manual pump which will perform one pump each period (e.g. 3ml fixed dose).

The downforce can be triggered perhaps by a small powerhead which fills the top container (with a wastegate) with water which will pump the container. Once the top container finishes draining, it will go up again. However, the force required is approximately 1.5kg based on the pressure I tested with an inverted digital scale.

To automatically pump 15ml (5 x 3 ml), we set the common 3-pin plug timer to go off/on at every 15 min interval for 5 times.

**TKS7011** · 3rd Jul 2009, 13:03

Originally Posted by Alvin Koh

The construction of your prototype is very solid! Almost looks like a final product.

Your idea got me to thinking about another method - which is commonly used - the pump bottle. However, perhaps the bottles can be encased within a large PVC cyclinder with a timed weight/downforce above the manual pump which will perform one pump each period (e.g. 3ml fixed dose).

The downforce can be triggered perhaps by a small powerhead which fills the top container (with a wastegate) with water which will pump the container. Once the top container finishes draining, it will go up again. However, the force required is approximately 1.5kg based on the pressure I tested with an inverted digital scale.

To automatically pump 15ml (5 x 3 ml), we set the common 3-pin plug timer to go off/on at every 15 min interval for 5 times.

Wow, nice illustration and interesting idea

I think it may work! Pls share your findings if you are planning to trial it out. Thanks!

**Alvin Koh** · 6th Jul 2009, 12:02

Originally Posted by TKS7011

Wow, nice illustration and interesting idea

I think it may work! Pls share your findings if you are planning to trial it out. Thanks!

I went to Daiso over the weekend and checked out the various pumps. The downforce required to pump the bottle is very high and may not be possible without high space requirements to house such a big load. The springs inside the pump mechanism need to be modified to reduce the force required - will update again if I have any findings.

**Shadow** · 6th Jul 2009, 12:45

my suggestion, drill hole on the pump bottle, connect air pump. Use the airpump to inject air into the bottle. that will push the fert out. Just idea, not sure if it is really work

**TKS7011** · 7th Jul 2009, 09:00

Originally Posted by Shadow

my suggestion, drill hole on the pump bottle, connect air pump. Use the airpump to inject air into the bottle. that will push the fert out. Just idea, not sure if it is really work

Would be good if it works! But I seriously doubt airpump can build enough pressure for this purpose... Anybody has spare CO2 bubble counter and airpump to test it out?

**fireblade** · 7th Jul 2009, 10:19

think your nozzle should not touch the water surface...
algea might formed there and you will have another equipment to clean

**TKS7011** · 23rd Jul 2009, 22:52

Originally Posted by fireblade

think your nozzle should not touch the water surface...
algea might formed there and you will have another equipment to clean

That was the initial idea to keep the nozzle above water. But there will always be some fertilizer residue at the nozzle and may cause it to choke when dry up. Putting it below water to solve this problem. So far so good, no sign of algae.