# Auto-dosing equipment and questions...



## Laith (Sep 4, 2004)

I'm putting together an auto-dosing setup for a new aquarium (200l) that I'm installing. Will be using two peristaltic pumps; one for macros and one for micros. I've got some questions:

- I want to dose directly into the output hoses of an Eheim 2126. These should work shouldn't they?:

http://www.aquazoo24.de/product_info.php?products_id=920&osCsid=9e2e12030b6268e955a63a71dd31b2ea

Any issue with getting two of these and putting them on the output hose?

- Can someone confirm these calculations for me?:

If I mix up 1 liter (1000ml) of water with the following: 30g KNO3, 12g K2SO4 and 12g KH2PO4, each 50 ml dose of this mix added to 175l effective water volume will give me 5.5mg/l of NO3, 5mg/l of K and 0.25mg/l of PO4?

And if I add 2.7g of CSM+B into 1000ml, 50ml of this solution will add 0.05mg/l of Fe into my tank?

The reason the above uses 50ml per dose is that I may choose the AM dual doser which has a minimum dose of 50ml/minute. This doser becomes more interesting than the APT doser (very small volumes per minute) if I decide to increase the stock solution in order to use it for top-off water as well (it will be an open top tank).

All inputs welcome!


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## Praxx42 (Mar 4, 2005)

My only concern is that you'd be plumbing the end of a light-pressure system (perstaltic) into the return for a higher-pressure system (Eheim). I know perstaltic pumps are supposed to prevent backflow, but that's under normal atmospheric pressure. I don't think, IMO, that they would be able to withstand the water pressure coming off the return from the Eheim.

And it's too early for me to be doing math.  Someone with more active braincells should be able to check your work.


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## IUnknown (Feb 24, 2004)

Yeah, I put a check valve right off the Tee. Also make sure the Tee is pointed up so that the minerals fall into the flow from gravity.


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## Laith (Sep 4, 2004)

Yes, check valves sound like a good idea.

Regarding the pressure from the Eheim, wouldn't the vast majority of that pressure be directed down the path of least resistance; straight down the larger diameter hose?

If the pressure is such an issue then how are the ferts going to enter the flow of water at all?


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## IUnknown (Feb 24, 2004)

I was thinking more of a barrier to keep from the fertilizer from mixing. The pressure might suck some of the fertilizer from the line.


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## Raul-7 (Feb 4, 2004)

Sorry to bud-in, but I have questions regarding auto-dosers that are of importance. Do you not worry about nutrients settling? In that case, how would you know you have a sufficient dose of each nutrient each time the doser turns on?


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## Laith (Sep 4, 2004)

Hehe... that was going to be one of my next questions! 

Anyone have a chance to double check my dosing calcs?


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