# PPS dosing: resolution



## felis (May 17, 2005)

Hello,

I am currently using PPS for my 75G 256W CF w/pressurized CO2. Today I have finished putting together an autodosing system which pumps liquids to inline CO2 reactor using 3 channel medical infusion pump. The stuff works very well so far on test liquids (water). Before putting it to service I'm trying to figure out what resolution of dosing is practical in order to dilute PPS solutions accordingly.

The pump works the following way: you set the infusion rate from 0.1ml/hr up in 0.1ml increments. Then you can either set the dose in 0.1ml increments, push button and then keep pushing the button every day or say "infuse all" and let it pump the whole 2l bottle to which I can also add fertilizing solution on the fly without stopping the system.

In second case dosing can be done in 2.4ml/day increments. I'm currently using plain cooking spoon set for dosing so my resolution is 1.25ml and it works OK; SS and PF are 5ml/day stable week to week, I'm still playing with TE which is 5ml/day currently and raising.

So, I have 4 choices:

1) Use original PPS recipe and have 2.4ml/day play. With current dosing rate I will be able to run on a single 2l bottle approximately for a year and a half.

2) Dilute in half to get 1.2ml/day play. In this case I will need to refill the system every 7 months.

3) Dilute in 2.4 to get 1ml/day play. I could then easily compare my dosing with other people's (0.1 ml/hr on the pump will be equal 1ml/day) and run 5.5 months between refills.

4) Dilute in 24 to get 2 drops (0.1ml) resolution. I will have to refill my 2l bottle twice a month. I also doubt that this resolution is practical when dosing 75G.

I would greatly appreciate any comments. Thanks,

/felis


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## Edward (May 25, 2004)

Hi felis
Your system sounds exciting and quite complicated. I was hoping somebody with dosing pumps experience will reply to your post so we can learn more about it. 
Any updates?

Thank you
Edward


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## plantbrain (Jan 23, 2004)

felis said:


> Hello,3) Dilute in 2.4 to get 1ml/day play. I could then easily compare my dosing with other people's (0.1 ml/hr on the pump will be equal 1ml/day) and run 5.5 months between refills.
> 
> 4) Dilute in 24 to get 2 drops (0.1ml) resolution. I will have to refill my 2l bottle twice a month. I also doubt that this resolution is practical when dosing 75G.
> 
> ...


I'd go something in the month's range between refills, this is plenty of time and also does not allow for that much evaporation, thus concentration of the reservior supply or fouling from fungus etc.

While it's automatic, things can still go squirrlely, double checking it once every so often is very wise.

If you want, buy a graduated cylinder with ml measurements and a cheap plastic one will do and is cheap. Use this to check the mls dosed over the time alotted.

I would dose the traces early, say 1 hour before the lights come on. Macro's late in the day.

Reagdrs, 
Tom Barr


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## felis (May 17, 2005)

plantbrain said:


> I would dose the traces early, say 1 hour before the lights come on. Macro's late in the day.


This pump doesn't have this ability, it either pumps all the time until the container is empty or stops after delivering the set amount.

The setup works around the clock for 3 weeks now. I'm using 1/2.5 PPS recipe. The doses are: 0.5ml/hr SS, 0.1ml/hr PF, and 0.5 ml/hr TE (it's approximately 5,1, and 5 ml of undiluted solutions a day). PO4 is stable at 1ppm, NO3 20-40. I'm not dosing Mg at all; when Ca and Mg (GH) drop I start using tap water for top-offs instead of DI until they raise again.


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## Edward (May 25, 2004)

Hi
I never experienced any problems dosing TE and macros at the same time. 

Edward


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## plantbrain (Jan 23, 2004)

Weak chelators such as gluconate, popular with SeaChem Flourish users,will form a milky precipitate when added with PO4, DTPH, ETDA and other stronger chelators will not and this does not apply nearly to the same degeree.

So having a more(although slightly) form of Fe versus a less but more readily available over the long term Fe does present a little difference in routines, but I think the differences are subtle. The difference beteween TMG vs Flourish are evident certainly, I like TMG is many respects, but both do very well.

Regards, 
Tom Barr


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