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Using a hydroponics fertiliser?

Ginkgo

Member
Joined
11 Mar 2018
Messages
26
Location
Devon
Hey there, I was browsing around for some cheap dry ferts and I stumbled upon a water soluble pre mix intended for growing tomatoes. It stood out to me because of the lack of ammoniacal & urea nitrogen, I'm thinking the only problem may be with the Sulphur content. This is intended for use in a plant cutting grow out tank that I'm thinking about setting up. It would also be handy to hold some excess fish fry it, but I'm unsure if the fertiliser would make the environment toxic for them.

Thoughts? any input would be appreciated.
ten.png
 
Joined
31 Aug 2020
Messages
79
Location
Cambridge
Sulphur is not a problem I think: it is only 1.8ppm of sulphate per 5ppm of Nitrate equivalent. So if you want to increase your NO3 by 5ppm in a 100l Tank, you could use the following calculation (fert-calc --calc target --fertilizers-db tomatogo.toml):


You need to add 1.2 grams of fertilizer to reach your target
Dose by elements
Element: N = 1.130 mg/l as NO3: 5.000 mg/l as NH4: 1.455 mg/l
Element: P = 0.801 mg/l as PO4: 2.456 mg/l as P2O5: 1.835 mg/l
Element: K = 4.220 mg/l as K2O: 5.083 mg/l
Element: Mg = 0.426 mg/l as MgO: 0.706 mg/l
Element: Fe = 0.021 mg/l
Element: Mn = 8.471 ug/l
Element: Zn = 3.812 ug/l
Element: B = 3.812 ug/l
Element: Cu = 0.565 ug/l
Element: Mo = 0.565 ug/l
Element: S = 0.622 mg/l as SO4: 1.863 mg/l

I would say, that the PO4 percentage comparing to NO3 is a bit too much for aquariums usage (like 3 times more). Microelements are also not sufficient for the macroelements amount. Just in case: I have used my calculator for this (Just another fertilisers dosing calculator).
 
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