MSU injectyion Ratio

[Gcroz]

I was curious about the proper injection ratio For MSU formula and my Dosatron. I have, in the past, used a 1:100 ratio for Dyna-Gro. There was no ratios listed on the label of the MSU.

Anyone have any suggestions or preferences on the ratio?

 

[Ray]

Your question actually has too many unknowns for anyone to give you a solid, specific answer.

What formula are you using?
What final concentration are you looking for?

If you used Dyna-Gro "Grow" formula (7-9-5) undiluted at 1:100 (7.68 teaspoons per gallon), you were feeding at over 700 ppm N (which I doubt).

Basically, you decide on whatever your final desired concentration should be, determine the amount of fertilizer per gallon that is, and make your concentrate 100x that for a 1:100 proportioner.

For example, let's say you want to use K-Lite (very similar to MSU RO) at about 50 ppm N with a 1:100 proportioning pump. For 50 ppm N, you need 1.45g per gallon of final solution, so your tank would require 1.45 x 100 = 145 g/gal.

 

[DavidCampen]

You really should get a conductivity tester so that you can verify that the Dosatron is giving you the ratio you expect. I have stopped using my Dosmatic because it was not reliable when working against a high backpressure. When I would take the spray nozzle off of my watering wand to collect a sample of the fertilizer solution and test the conductivity it would match my expectation but when I would put the spray nozzle on so that there was a high backpressure while collecting the solution for testing then I would find the conductivity to be much lower than I expected - this was using the Dosmatic MiniDos and I find the Dosmatic MicroDos to be even more problematic.

Now I prepare my fertilizer solution in a tank and use a diaphragm pump of the same type that I use for my RO system to deliver the solution to my watering wand.

 

[Ray]

What hose and nozzle are you using, David, and where was the dosing pump in relation to the pump?

I have a Mini-DOS 2.5% downstream from my shallow-well pump, and it flows through 25' of 5/8" garden hose having a large "Red Head" Dramm water breaker on it. My measured conductivity on the outlet matches my calculated concentration quite well.

Putting the metering pump in a large pipe on the feed side of the pump should eliminate any back-pressure issues.

 

[gonewild]

I have stopped using my Dosmatic because it was not reliable when working against a high backpressure. When I would take the spray nozzle off of my watering wand to collect a sample of the fertilizer solution and test the conductivity it would match my expectation but when I would put the spray nozzle on so that there was a high backpressure while collecting the solution for testing then I would find the conductivity to be much lower than I expected -

Most fertilizer injectors/proportioners have a minimum flow rate. It probably is not back pressure but rather the low flow rate. It's almost the same thing but not quite.