Mixing Ferts?

[Amiga276]

I would like to pre-measure ferts for my buddy who is going to take care of my tank while I am away. Is mixing the Flourish products into pre-portioned doses ok? (Excel, Flourish, Iron and KNO3)

[Aaron]

It's probably best to leave them separate.

[Amiga276]

cool, thanks!

[John G]

It's probably best to leave them separate.

Why?

[SCMurphy]

For example, things like phosphate and iron will combine and precipitate from the solution. Which is fine if you are encouraging root feeding plants and the precipitate makes it into the substrate, past your filter.

[John G]

things like phosphate and iron will combine and precipitate from the solution.

I still don't understand (not surprising, since the last chemistry course I took was in 1957, in high school)--Seachem's Florish has both phosphate (as P2O5) and iron in it. Why don't they combine and precipitate out? Why does adding other stuff make them do it?

[Aaron]

Perhaps the P2O5 compound doesn't react the same as PO4?

[SCMurphy]

Its a combination of factors, light and O2 and pH shifts that changes the effectiveness of the chelator they use to hold iron in solution and that gives the P the opportunity to latch onto an Fe. In the Flourish bottle after you open it eventually you get the precipitate, SeaChem can't hold them apart forever, just long enough to use up most of the bottle. Mixing the different ferts together, as the thread started, accelerates the process.

[John G]

I sent a note to Seachem about mixing them. Here's their reply:

"It is possible to combine most of our supplements together into 1 main dosing solution.....but not all of them. I suggest leaving out the Flourish Phosphorus and dosing it separately. If you tend to dose our Flourish Excel liberally you may opt to dose that separately as well. But the suggested amount should be fine in the main dosing solution.


Best Regards,
Seachem Technical Support,rb"

[krisw]

So, essentially, they're saying the same thing Sean is, right? Phorphorus is a problem when mixing. Otherwise, you can do it, but your control over individual elements will be diminished. I had bad experiences using a PMDD pre-mix from Greg Watson where everything but P was mixed together. After dosing seperately, the tank's looking much better. Amiga, I imagine that as a temporary solution for your friend to dose for a couple weeks while you're away won't be a problem. Long term, you might want to keep 'em seperate.