Poor Mans Auto Dosing, Take III

[magicmagni]

A factor to consider is the type of Iron you are using. The type of chelation probably is a factor. I noticed a "white" cloud before when dosing large amounts of SC Flourish Iron which is Iron Glutonate?, but with Tropica master grow I do not (EDTA Iron I think?). The point is that with one I was actually seeing a more yellow growth and the other I'm seeing greener growth it seems.

[Wasserpest]

I see your point Robert, but... it just doesn't sound right to me. If a little phosphate precipitates a little iron, our tanks would be permanently lacking iron, unless the P happened to be zero.

Obviously that isn't the case, so my assumption is that it has to do with concentrations. You can not put phosphate into your dosing container that includes iron, because it certainly will lead to precipitation. If you are spooning in the stuff per EI, you get problems as well due to the higher concentrations. If I dose 12 ml Flourish Iron and 1 ppm Phosphates over the course of two weeks the concentrations are so low that no precipitation occurs in the tank, even if dosed at the same time.

Of course with all assumptions... you know how that goes.

But think about the coexistence of Iron and Phosphate in a tank.

[scolley]

Originally Posted by Wasserpest

it just doesn't sound right to me. If a little phosphate precipitates a little iron, our tanks would be permanently lacking iron, unless the P happened to be zero.

Which is exactly why discussions of alternating micros vs. macros, one day one thing and the next day the other, just for the avoidance of problems mixing the two is bunk IMO.

It's time to bury that myth if you asked me... no basis for it, for exactly the reasons you stated above.

[Naja002]

But think about the coexistence of Iron and Phosphate in a tank.

I was thinking about it as I was typing it--and in ways it doesn't make any sense....But I'm not a chemist and I don't claim to fully understand all the ins and outs of these things.

That said, Why Doesn't the P that's already in the tank precipitate the Iron that we add...??? Many of us add little or no P--so its always there--regardless of alternating days or anything else. Every time we add Iron--the P is already in the tank--Soooo, why doesn't it precipitate the Iron and render it useless--I don't know.

Maybe:

We add sufficiently enough Iron to overcome the precipitive ability of the P that's in the tank...!?! (Yes: Concentrations). Maybe adding X amount of Plantex (or whatever) would give a Higher Iron reading on the same tank--if it was tested after being added when there were no P vs. When P was high--I don't know. Maybe, X amount of P only has the ability to precipitate X amount of Iron. Then we get into MagicMagni's thoughts on "Types" of Iron. There are different types of Nitrates (NH4, N03)...Are there different "Types" of Phosphates...? I have no idea. Is the phoshpate that naturally occurs in the tank somehow "different" than the phosphate that we dose---I don't know. NH4 occurs in the tank naturally, but we dose NO3.

Truth is: I don't have all of these answers. And to a Degree I am just passing along what "I've Heard". But, that said: I have Heard it more than just here at PT. The Tech Support at SC pointed out the P precipitation issue in the thread that I referenced earlier. They are in the Aquarium chemical business and they make good products, so I am willing to factor all of that in to its credibility.

I have little doubt that P precipitates Fe. Exactly how it works and all the details of it--I'm under-educated....

[Wasserpest]

I think we basically agree The fact that P precipitates Iron, there is no question about it. This has been proven when adding various elements together in one highly concentrated mix. Can't do that.

But, like Steve suggested, someone took this a step further and suggested to alternate days of dosing. And I don't think that is really necessary IF YOU ARE DOSING WEAK SOLUTIONS of fertilizers into the large tank volume.

If you add one weeks worth of P and one weeks worth of Fe side by side, at the same time, sure you'll see a white shower.

If you add one days worth of P, dissolved in quite a bit of water, and one days worth of Fe, also dissolved in quite a bit of water (as it happens in this autodosing setup) I think the concentrations are weak enough to prevent any sort of precipitation.

I guess this is up to you (the reader) how to do this, just like water changes, lighting a tank, or feeding your fish... everyone does it a little differently.

[scolley]

Originally Posted by Wasserpest

If you add one days worth of P, dissolved in quite a bit of water, and one days worth of Fe, also dissolved in quite a bit of water (as it happens in this autodosing setup) I think the concentrations are weak enough to prevent any sort of precipitation.

Well said! And if this still worries someone... add one days worth of P, give it a big stir (or wait 5 minutes) and then add one days worth of Fe.

[Naja002]

Originally Posted by Wasserpest

I think

Those are the keywords....

How to do any of this is up to the individual. But P/Fe precipitation is not--that's up to chemistry. Its not subjective, its Objective.

The fact is: the 3 of us combined don't know enough about it to form anything more than opinions based upon whatever we happen to feel about whatever we happen to factor in, leave out, etc, etc, etc.

We are just going around in circles, because none of us knows the facts....

[Naja002]

Wouldn't you SEE any precipitation as a white shower?

I will add this:

I have seen it before, but not really paid much attention to it, because I guess I really didn't understand what it was. But since this conversation--it seems pretty obvious to me....

My 55gal is heavily planted, with fish, fry, shrimp, snails and clams. The 2x that I have tested it for P--they were off the chart: +3. As stated in another thread--I have just started dosing regularly and heavily (K, Iron, Mg, Micros). When I added the ferts the first 3-4 times--it clouded for a while--couple of hours. I have very little doubt now, that the cloud is the "White Shower" that You refer to and is the high P in the tank precipitating the High Iron that I added--SC 10ml=~0.2 in the 55gal., plus Flourish.

Ok, I just added SC 10ml Iron (=~0.2ppm) to the 55gal. with no clouding--that's what I thought I remembered seeing: 2 days heavy clouding, next 2 days not so bad at all and none since.

The only way I'm going to know is to test P. I did a 50% water change a few days ago--so that may have helped the P situation.

I have way too many things that I need to get done today--which I am currently not doing as I sit on these boards--procrastinating! So, I doubt that I will get to testing the P today, but that would be a good way to help keep from doing the stuff that I Should be doing.......hmmmmm

[Wasserpest]

See, that's the difference. Your P levels being 3+, mine being one tenth of that. You adding 10ml Iron, me adding 1ml Iron.

With "you" and "me" I don't mean you and me, but just any person A or B or X or Y or what.

Interestingly, after all my vehement attacking of your theory I changed my autodosing from two bottles (micros and macros) to one bottle (everything except P). LOL!

[Naja002]

See, that's the difference. Your P levels being 3+, mine being one tenth of that. You adding 10ml Iron, me adding 1ml Iron.

But think about it:

Your P is 1/10th of mine. You are adding 1/10th the amount of Iron. Your ratio of 1:10 is the same as mine. The difference is that You may not have sufficient precipitation (in absolute quantity) to See it with your eyes. It doesn't mean that its not occuring--just that its not producing enough white cloud for you to notice or see. Additionally, Your tank is roughly twice the volume of water of mine, but the P/Fe ratio is still 1:10.

Because I am adding 10x as much to half the volume of water--I can see it from the front of the tank and from the side view.

You may still be getting a huge amount of preicipitation--in reference to the absolute amount of P vs Fe. The P may even be precipitating 100% of the Fe--who knows?

We are still at the point where we don't know enough to really debate it. And I don't forsee me having the time to research it in the near future. BUT I think this shows/indicates that the Iron we add Will be precipitated by the P that is already in the tank, in whatever form it is. How much?--I don't know. Does P have a Max precipative limit?-I don't know.

There's just too many details about this that I am unaware of.....

Interestingly, after all my vehement attacking of your theory I changed my autodosing from two bottles (micros and macros) to one bottle (everything except P). LOL!

That's Good! The only problem that I am aware of is with P. Everything else gets along fine--from what I have learned/understand. You may just end up needing to add more Iron to Your daily dosing in order to overcome any P precipitation. If You show up with what appears to be an Iron deficiency--then just add more Iron to Your auto-doser.

From what I've seen: it Appears that P has a Max precipitation limit--I don't know this: I'm just putting 2+2 together from what I have seen.... Edit: This may vary well be incorrect because of the various possible reasons listed below for the reduction in P: See Edit Note.

Edit Note: It was bothering me whether my P was +3 or +0.3, so I looked at the test scale and it was definitely +3. While I had it out I glanced at the instructions and remembered that P is a quick simple test--so I went ahead and did it. The results are: 0.1-0.15. The reduction in P is no doubt from the water change and a reduction in feeding--both quantity and frequency. But the question to me remains: Does P precipitating Fe cause any reduction in P? I guess I can kind of check that out over time by doing back to back tests--before and after adding iron.

I guess the reduction in P could also be caused by the Increase in everything else as I am dosing more.....Plants using more P.

Edit Note 2: The 1:10 ratio of P/Fe above is incorrect. The ratio of P/Fe is actually about 30:1. The ratio between My setup and Wasserpest's is 1:10. I have left it the way it is simply because it reads well for getting the point across....

HTH

[hamstermann]

Was it ever decided what causes the smell and the growth in the ferts solutions?

[Wasserpest]

In my dosing setups, removing the P (KH2PO4) from the mixture seemed to resolve the smell issue. Nowadays I mix N (KNO3) and K (K2SO4) and perhaps a little bit of Mg (MgSO4) and after four weeks, the solutions have a slight odor, but not the wetsocksngarlic gag smell.

I dose P via test tube.

I dose micros in concentrated form via peristaltic pumps. In dilution, those tended to grow some stuff (fungus? bacteria?) which can probably be suppressed with HCl. But I found peristaltic pumps work well to dose Flourish and such liquid trace mixes, so I stopped experimenting.