Fertilizer Injection Systems

[Allen Repashy]

Does anyone have experience with Fertigation Systems? I want to set up an injection system so I can have constant fertilization for watering benches as well as spot spitters.

I have eliminated the venturi type for my needs because of pressure differential requirements and metering inaccuracy.

I do not want to use a system that requires electric or pneumatic power.. such as Anderson..

So it narrows it down to water powered metering systems. The two main systems I am looking at are the Smith Measuremix and the Dosmatic or Dosatron

The Smith is an all bulletproof all brass and stainless unit that weighs in at 150 pounds for a 1/12" pipe size unit..... I know of units running for 20 years with zero service.

vs. the Plastic Dosmatic.... requiring yearly maintenance, and about half the price.

The main difference in function between the two is the Dosmatic type has an adjustable mixture ratio. from 1:40 to 1:500

Where the Smith is a fixed gear design that is ordered at 1:100, or 1:200 ratios.....

So does anyone have experience with these units, or maybe something better that I haven't found?

It would be nice to change the concentration on the fly for different benches or plant types....... but it is worth the effort?

It is possible to have multiple tanks with different strength mixes so that you could change mixtures with flow valves..... Or just use a smaller tank and fill it with the strength you need for the job..... a bit of work I think.

Anyone?

[Tim Harvey]

Yearly maintenance for a Dosatron? I've used one for the last 3 years without intervention.

I keep it away from direct sunlight, and have it set at 2% dilution. I modify my supply solutions to work with this ratio.

Of course, I'm small-scale and use the 10 gpm version.

T

[Allen Repashy]

Hi Tim, thanks for the comments. I have read that the Dosatron is simpler than the Dosamatic, but that they require maintenance such as replacing the seals once a year...... and cleaning the internal filter once a month! Maybe you should consider this after three years http://www.dosatronusa.com/userfiles...g%20Manual.pdf

It sounds like you are pretty happy with the unit. I am looking for a similar size unit to the one you have. Just out of curiousity, why are you using a 2% solution? it seems that .5% and 1% are the most common and require a smaller tank...

Allen

[Tim Harvey]

Well, it seems to be working perfectly still. I may open it up and have a look.

Many chemicals or fertilisers one might want to apply are simply not concentrated enough to use at 1% dilution rate.

T

[Zeroscraper]

I've started something new this year... tables with a rim around them covered in pond liner, which, of course, comes up to the top of the rim. Then I just put some soluble fertilizer on the table (I've been using fish fert but one could just as well use a synthetic fertilizer) and fill the tabletop with water from the hose, making sure to spray the spot where I placed the fertilizer so it gets thoroughly mixed. So far so good... when using water soluble fertilizer I've always had much better results by soaking the plants rather than just applying it from the top. As long as the plants aren't already soaked, the pots soak it all up.

[agavegreg]

If you have hard water and always let the water soak up from the bottom without flushing the excess salts out, you will run into problems. Just make sure to flush periodically!

[Zeroscraper]

Excellent reminder, but fortunately that's not a problem around here. I use a combination of rainwater, well water and Dungeness River water, none of which seem to cause any problems with my fert. method.... yet.

[thistlesifter]

Allen,

I've researched injectors/pumps for last six months.

Curious as to your statement

I do not want to use a system that requires electric or pneumatic power

. I presume your reason for this are logistic support issues.

Do you have any other considerations for elimination consideration of H.E. Anderson line of fertigation injectors?

Bob

[Allen Repashy]

Hi Bob,

Yeah, it is strictly a logistical issue, it would be a considerable expense to get power to where I need it, but after quite a bit of research, the Anderson system seems to be where many who try other types first end up going to. I have been rethinking the costs vs. having to upgrade later because of issues.

The air modified Anderson seems the ultimate setup. H.E. Anderson Products

Problem is that in my ultimate bench buildup, I see a need to run three injectors... One for acid, one for base fertilizer, one for calcium nitrate... or course, that would be in a perfect world.... and require me winning the lottery LOL...

[Allen Repashy]

Here is some interesting reading for advanced system setups.

http://agroponic.com/pdf/tree_improvement_1.pdf
http://agroponic.com/pdf/tree_improvement_2.pdf

[thistlesifter]

The electrical option for Anderson system can be as simple as a battery charged with a 12V Solar cell. It is needed for control, among other things, if there is a need for a periodic auto adustment for PH (either based on change in input of based on change of crop).

Electrical power or pnuematic is a requirement to regulate control of the amendment drip pulse. Pnuematic is the preferred system for me as it prevents the need to deal with the waste chemical that is a product of using the electrical control system to control chemical drip. I'm assured it isn't as big a deal as I imagined it could be. Small compressed gas (CO2 or?) tank will last a long time.

If you don't want:
1 . real time control via an RS232 interface and their software running a your computer or

2. a locally hard_programmed microprosser,

and if you opt for pnuematic option, electrical power isn't needed.

So far, until I talk to the Calif field reps and unless they can explain something more than I learned from the home office, Im leaning toward goingi with the pnuematic option.

I still haven't had a chance to talk to the Smith Pump people.

The Anderson folks are helpful. They are down to earth, real people that understand and are happy to answer anything I've thrown at them. I am told this is the kind free lifetime support you can expect from Anderson and more. (Your lifetime, not the systems)...I'm quite sure the system will outlive me.

Bob

[Allen Repashy]

Hi Bob,

Great info. sounds like we are on the same path... maybe we can get a combined discount if we both go a similar route.

I HAVE talked to the Smith people, and they are equally helpful. These things will probably outlive a "Twinkie" LOL....

The two deal breakers for me at least are:

1. The fact that that it doesn't seem possible to have a unit that will work with both low flow and high flow because the unit works as a hydro-motor of sorts, and takes a certain amount of pressure and flow to get the pump going... If you want one unit that will work with a single hose AND a wide open 1 1/2" pipe (to do rows of benches or spitter/drippers) you can't do it without having two different pumps. (they are very expensive units)

2. You are absolutely limited to the engineered mix ratio of the pump as delivered, so can not change anything but your dilution ratio to make delivery adjustments. They do offer a two head pump that can be used for delivery of two different solutions... or doubling up to double the delivery ratio.. but that is it.

If you have a "Set and Forget" type requirement, I think you couldn't find a better piece of equipment... but for varied needs and flows, or computer control, the Anderson would be the answer for sure.....