# Is Auto-Dosing Right For You?



## Praxx42 (Mar 4, 2005)

Yes, I'm posting in here again. Move over, manifold... autoDose's got ya covered! And because I'm a DFWAPCer, this will be out later on the DFWAPC site with pictures, whistles, spinning tops, fireworks and belly button rings.
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We've all been there: "Again? Let me get the mL dropper and gram scale out&#8230;" I don't know about the rest of you, especially if you're like me and have giant and/or multiple tanks, but I have gotten tired of daily dosing. While necessary, it can be quite tedious even if you know the particular "recipe" that your tank needs on a daily basis.

For me, the issue came to a head while I was working as a service technician at the biggest LFS in town. In addition to my own 5+ tanks, I was caring for 120 or so other tanks during the course of a month. Let me tell you, it was killing my interest in the hobby, especially the daily care of my own tanks. I would accidentally skip a day or three of dosing my plants in the rush to get to work, so I decided to do something about it. I kept thinking, "If there's a way to dose saltwater tanks for chemicals every day, I've GOT to be able to do the same thing for my plants."

Hence the year and a half of research I've done in an effort to uncomplicate my mornings. Let's get to the stats, shall we?

*The Tank:*
240 gallon trimless/160 gallon actual water volume
Two 400W MH light fixtures, at staggered intervals (2.5WPG with 5WPG at peak)
Natural Gravel substrate

*The Chemicals:* (I use EI, so YMMV)
Magnesium: 4 tsp at weekly water change
Potassium: 3 tsp at water change
Nitrates: 1 ½ tsp weekly
PlantexCSM+B: 20 mL at water change and 50 mL weekly
Phosphates: 15 drops at water change and 1 mL weekly
Iodine: 5 mL at water change

Through various experiments, I discovered that I needed to dose Nitrates, Phosphates and Plantex during the week. It wasn't an issue at first, but as I got busier at work, my regularity at dosing got worse and worse. Since I had cheap access to various equipment through work, I tinkered around with making an automatic dosing system to keep the tank happier. I first tried the Kent Aquadoser, which worked initially but became worthless after a couple of weeks due to the oxidizing nature of the Fe in Plantex.

I finally came around to the peristaltic pump. If you're not familiar with these, here's a short description:


> Peristaltic pumps use rotating rollers pressed against special flexible tubing to create a pressurized flow. The tube is compressed at a number of points in contact with the rollers or shoes. The media is moved through the tube with each rotating motion. The individual components of peristaltic pumps include a pump head, drive, and tubing. Peristaltic pumps are also referred to as flexible member pumps, flexible tube pumps, dispensing pumps, or dosing pumps. The advantages of peristaltic pumps are that the components of the pump may be chosen when the integrity of the media is a requirement of the application since the fluid type does not contact any internal parts. Seals and valves are not needed as in other pumps.


In other words, a pump that can deliver tiny amounts of liquid, can't backflow, and can run dry without destroying itself. Perfect! I ordered mine from (shameless plug) DrsFosterSmith.Com. It's called the SP-3000 Dosing Pump. This lil' baby pumps 50mL a minute and uses normal airline tubing for its connections. Once it came in, I began gathering my parts for my top-off/dosing system:

SP-3000 Dosing Pump
20' airline tubing
check valve (just in case)
10 gallon aquarium/sump
digital timer from Home Depot

I assembled all the parts. The sump went under the main tank, tilted slightly upward to create a low point. The drawing end of the tubing was placed in the low corner and a small weight on top of the tube to keep it in place. The airline tubing was attached to the pump, and I put the check valve on the end that was placed in the tank. The digital timer received two backup batteries, set to deliver the dose in the morning before the lights come on, was plugged into a power strip and then plugged into the timer. I also noticed that I was evaporating about 8 gallons of water a week, so I filled up the sump to 8 gallons, poured in my Plantex, Nitrates and Phosphates.

This is where the problems started, as some of you are no doubt groaning about as you read this. Due to the oxidation of the Fe in the Plantex, the feed lines quickly became fouled and useless. Once exposed to light for extended periods, Plantex will become almost a gunk instead of a liquid&#8230; *once exposed to light.* This lead to a modification of the system: I replaced all of the transparent feeder lines with thick black gasoline feeder lines from AutoZone. I would have used black Ozone tubing from DrsFoster, but it wasn't available at the time. I also had to completely cover the sump with towels to prevent as much light as possible from reaching my dosing solution. However, regardless of how well I have covered the sump, some light still tends to come thru&#8230; which means every water change, I wash the sump out and clean out a little gunk while I am at it. A small price to pay&#8230; after all, we should all be used to cleaning up "gunk" by now.

This particular system has been up and running for over a year. I can say I am pretty happy with it, aside from a little light spillage.

Now, I am sure some of you are thinking, "You can't dose PO4 and Fe without the PO4 screwing over the Fe. Especially if they're going to be sitting in a pail of water together for 6 days." Yes, I have read that too, but truly, I have NO problems with it. I attribute that (maybe incorrectly) to the lack of light in the sump. Very little of the Fe oxidizes in the dark, IME. I can maintain Fe levels of 0.1 and PO4 levels of 0.5 with this system, consistently, without issue. I heavily recommend that if you decide to try this particular dosing system, you must ensure that your chemicals remain in the dark until they hit the tank water.

Now, there are other types of peristaltic/dosing pumps that have multiple feeds, such as the Aqua Medic Reefdoser - Quadro from MarineDepot.Com or a Vario model that uses multiple RO feed lines. Use of these models would allow you to separate your chemicals with no problem and dose specific quantities independently. While I can attest to the extreme durability of the SP 3000 model, I don't currently have the finances to buy a multiple pump model to test out. I am sure that with the correct calculations, you should have no problem utilizing a multiple-pump system. *And if you feel like donating to Praxx's Lab-A-Ratory, I surely won't turn you away and you will receive credit for funding important aquarium research! LOL*

Do you need an automatic dosing system? That is entirely up to you&#8230; but I can tell you it will make your life just a little easier. If you decide to use this system, please drop me a line with the specifics to:

[email protected]


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## turtlehead (Nov 27, 2004)

do you have any pictures instructions on how to do this? I would like to try it.


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## Praxx42 (Mar 4, 2005)

I don't have any diagrams, yet. I'm collecting pix for my article on DFWAPC tho. Check this thread again on Monday afternoon.


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## Laith (Sep 4, 2004)

Great article! Many thanks.

I'm thinking of doing exactly that type of setup though with a double pump: one for KNO3, K2SO4 and KH2PO4 and the second one for Plantex CSM+B.

It would be great to have more info on how you calculated the concentrations needed in your holding container as well as how you calculated the on/off periods with the timer to add the right amount to the tank.


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## Praxx42 (Mar 4, 2005)

Laith said:


> It would be great to have more info on how you calculated the concentrations needed in your holding container as well as how you calculated the on/off periods with the timer to add the right amount to the tank.


That was the easy part. To determine how much ferts I would need for the dosing sump, I just added up all the doses I was previously adding during the week. I added those ferts in with the amount of water I calculated I was loosing to evaporation during a 6-day period.

To calculate how long the timer should be on every day, I took the total amount of fluid in the sump and divided that by 6 (I don't autoDose on the day I do my water change). Then I took that amount and converted it into milliliters. I looked up how many milliliters a minute that my peristaltic pump delivers, and divided my daily amount of fluid in the sump by that number, which gave me how many minutes the pump needed to be on.

For Example:
Your tank looses 1 gallon a day to evaporation. Your pump moves 50 mL a minute. Therefore-

6 gallons in the sump, one per day.
One gallon = 3.78540 litres = 3785.40 mL a day
3785.40 mL / 50 mL a minute = 75.708 minutes

So, in this example, you would run your pump for 76 minutes to top-off the tank and replenish all the ferts. If you were dosing all the ferts separately, you could use a lower amount of fluid, shortening the amount of time your pump needs to run.


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## Laith (Sep 4, 2004)

Ok that makes perfect sense. Thanks.


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## IUnknown (Feb 24, 2004)

This is my experience with auto dosing. Been running for about 6 months now. I never have to think about fertilization, just trim and change water on the weekends.
http://aquascapingjournals.com/journals/diy_automated_dosing.htm
old thread,
http://www.aquaticplantcentral.com/forumapc/showthread.php?t=2146&highlight=auto+dosing


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## Raul-7 (Feb 4, 2004)

This seems like a great idea, but how are you sure the pump is giving out even concentrations of nutrients? I mean nutrients tend to settle, so there needs to be a mixing action to ensure there's an equal amount of nutrient output.


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## Praxx42 (Mar 4, 2005)

True. Perhaps a tiny Rio or Azoo powerhead might be added to the sump, along with a digital timer to ensure that the PH shuts off before the sump drains below the active level for the PH.

Note that nowhere in this thread did I say I came up with a perfect solution.  Commentary such as yours only builds up the available information. One day... yes, one day we WILL have the answer!


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