EI, why no magnesium? PPS pro, why magnesium?

[JackBlasto]

Hoping to get some input on why one fert method (pps) uses magnesium and the other does not (EI)? Is EI relying on the magnesium level commonly found in tap water or is magnesium simply not a big deal in that method?

Also why is calcium not dosed in either of these methods? Once again, are they relying on minimal amount of calcium from tap water?

I have been trying to do a rather complicated RO water mix that has left a lot of things overlooked as I learn (like calcium and magnesium) and my plants look like a science experiment for those deficiencies (which is kind of cool and fun to know now BUT I want to get this right and refine my weaknesses

Just very curious as to why the two methods differ greatly with their inclusion and exclusion of magnesium and the reasons for that? Any thoughts on calcium being overlooked in both methods would be appreciated as well.

Thank you.

 

[Billbug68]

Most of us here who dose pps pro don't add the magnesium. There should be enough magnesium and ca in the tap. Is there a particular reason you're using RO? Sensitive inverts or fish? Just wondering... In most cases, tap should be fine.

 

[JackBlasto]

Discus tank... I'd love to be able to use tap water but silly me thought that this discus tank was going to be easier.

 

[Mebbid]

Ahhh that's understandable. Have you thought about going full ro/di and then mixing your water to remineralize it? That would be the way I would go for a planted discus tank.

 

[JackBlasto]

That's sort of what I've been doing... granted I didn't know what I was doing at first and thus neglected magnesium and calcium at first.

Is there any way to easily do a comprehensive list of minerals that are essential?... I just added Discus trace and Flourish (just plain old flourish... it has small amounts of minerals in it) to my regimen of dosing now that I've realized that I was missing a lot by just dosing PPS pro... Do you think by adding these two that I'm covering all my bases?

 

[Mebbid]

Try taking a look at this product. It is made for ro/di water

Seachem. Replenish

 

[JackBlasto]

Looks good and that IS what I was looking for but I'm hesitant because it raises the GH... Right now I have a dGH and dKH of 3 which translates to 53.7 ppm GH/KH

This seems to be what Discus people aim for. If I boost it 1 GH I'm leaving my target area... although I'm at a loss right now for the lesser evil... I mean I don't want to be neglecting nutrients.

 

[JackBlasto]

PPS Pro- MgSO4 Why is 20 grams recommended?

Wondering why the recommended mix for PPS pro

K2SO4 – 29 grams
KNO3 – 33 grams
KH2PO4 – 3 grams
MgSO4 – 20 grams


mixed in a 500 mL bottle of RO water

and dosed 1mL per 10 gallons

when I input the dose of 20 grams MgSO4 into a dosing calculator Yet Another Nutrient Calculator

it says the resulting ppm is 0.10

It seems that PPS pro's target is around 2.0 ppm so what am I missing here? Why is 20 grams recommended? It seems like it should be MUCH more?

 

[aqua_chem]

I've merged two of your threads asking about magnesium as I think they are essentially asking about the same thing.


Something to understand about magnesium is that it's not in particularly high demand. Depending on your literature source, magnesium makes a bit less of a contribution to the dry mass of a plant as phosphate (actual 50-100%). Now, phosphate levels are generally thought to be sufficient at 1-2 ppm or so, so it's safe to assume that the magnesium requirements would be 50-100% of that. As it turns out, the daily dose of Mg and PO4 in PPS is the same, about .1 ppm, which is what you're seeing in the numbers you're generating. If you dose to 1 ppm of Mg++ weekly, you should be covered; this is roughly .25 dGH. EI omits it largely because it assumes you're either dosing in tap water (good change of having decent Mg) or are reconstituting RODI (which will be adding Mg). Either way, EI also includes Mg in the CSM+B that would help offset this lacking if the need arose.


Interesting aside, one of the major CA cities with an available water report had 50 ppm Mg out of the tap. Yowza!